Author: naturehydro

Among work crews in the Santa Maria Valley we find mestizo campesinos, Mixtec and Zapotec Indians, and Mexican urbanites from, for example, Mexico City, Guadalajara, and Monterrey. We have, to be sure, identified school teachers and university graduates laboring in the fields. An examination of the valley’s agricultural labor force from the perspective of crops, as we did above, provides vital information regarding the number and flow of workers, but it reveals little about the labor force itself. To capture meaningful information on farm workers that will enable the observer to recognize behavioral regularities, educe patterns, and formulate typologies, it is necessary to observe and query the farm worker directly. We propose to accomplish this here by focusing attention on three fundamental circumstances regarding the farm worker’s life: where does s/he keep a permanent home; what is the nature of the family that inhabits that home; and what role does s/he play in the household. Answers to these three queries elicited from farm workers observed and interviewed in the valley’s fruit and vegetable fields during the 1993 campaign, allow us to distinguish five distinct types of farm workers and farm worker families from the vast and increasingly diverse universe of farm workers that people the Santa Maria Valley: the immigrant worker who has settled permanently in the valley and severed most economic ties and responsibilities with the home community in Mexico; the binational worker who maintains two functional homes, one on each side of the border, and who constantly moves back and forth between them; the Mexico-based migrant who periodically leaves home and family in search of employment and wages; the border migrantócommuterówho, using a home base in the United States-Mexico border area, collection pot accesses an assortment of job opportunities in both countries; and the seemingly single, unattached, “homeless” migrant who spontaneously and unsolicited appears in the valley looking for work.

A review of the circumstances that govern the lives of these farm workers, aside from providing interesting insights and improved understanding, allows us to identify and highlight some of the challenges and impediments that exist to correctly detect and enumerate them by, among other interested parties, the Census Bureau. Before undertaking the description and examination of the five categories of farm workers enumerated above, it is necessary to make two clarifications regarding limitations of the proposed typology. First, although the five types may suggest the logical stages of a migrationimmigration continuum, they are most definitely not. Each, in fact, represents an outcome in itself; an arrangement arrived at by design on the part of the farm worker and not a step in a process leading to settlement. Second, the described outcomes are at best temporary, passing adjustments to an ever-changing and highly unpredictable environment, one which is not only the product of agriculture’s inherent uncertainties but which is also encumbered by recent, momentous developments. Among those developments responsible for propelling change to a state of almost perpetual, unrelenting flux, to mention only the most obvious, are the rapid transformation of California agriculture and its employment practices, the never-ending changes to immigration laws and vacillating if not contradictory enforcement measures, and the changing conditions in Mexico and in the farm workers’ home communities which can either inhibit or foster migratory practices. It would be venturesome and inappropriate, therefore, to claim that the proposed characterizations represent more than current adaptations to current conditions which may change inadvertently and, once again, force farm workers and farm employers to hastily rethink and readjust their current modi operandi. As noted above, over 10,000 immigrant farm workers have settled in the Santa Maria Valley.

Many have done it permanently, which means they have relinquished their place and position in the home community, severed economic ties and responsibilities with the home-based family, and transplanted dependents to the valley. Immigrant farm workers often travel to Mexico to visit family and friends, sometimes on a regular annual schedule, but their roots are now fixed in Santa Maria. One way of ascertaining that permanent settlement has in effect taken place is when the producer and consumer components of a given domestic group are living together in the valley on the basis of locally derived income and wages. The vast majority of Santa Maria’s immigrant families come from just three states located in the central part of Mexico: Michoacan, Jalisco, and Guanajuato. The others are from northern border states such as Durango and Chihuahua , Mexico City , and the southern state of Oaxaca . Starting in 1964, a succession of at least three immigration waves populated the valley with its current mass of settled farm workers. Although prior to 1964 some farm workers had already settled in the valley forming small, marginal colonias or barrios within the towns of Guadalupe and Santa Maria, it was the elimination of the program that actually precipitated the first important movement of ex-braceros towards settlement. This action was enthusiastically urged and even abetted by local growers who feared they would otherwise lose access to their labor supply and, especially, their most skilled, trusted, and reliable workers. A second wave in 1975-1985 accompanied the expansion of high-value, labor-intensive, specialty crops which, as already discussed, created a bounty of new farm jobs with longer employment seasons. Growers once again encouraged and helped migrant employees to settle in order to ensure the presence and availability of a stable, reliable labor supply to tend valuable and highly perishable farm commodities. The third and most recent wave was prompted by IRCA and its special provisions for farm workers which were designed specifically to accommodate the interests and needs of the agricultural industry.

IRCA accomplished two things in the Santa Maria Valley: On one hand, it created a unique opportunity for many settled yet undocumented/unauthorized immigrants from earlier waves to legalize; and, on the other, it encouraged a new cohort of migrant farm workers to emulate the experience of preceding generations by also settling down. Surveys conducted in 1991 and 1993 among fruit and vegetable workers in the valley reveal that immigrants enjoy the best farm jobs, either as skilled full-time employees or in vegetable harvest crews which offer nearly year-round intermittent jobs. In fact, 74 percent of all immigrant farm workers are employed by the vegetable industry. Typically, for example, a broccoli cutter earns $1,000 to $1,200 monthly during at least nine to ten months of the year; while, in contrast, a strawberry picker earns $500 to $800 monthly during, at best, five to six months of the year. Vegetable employment and wages, in short, allow workers to minimally provide for a family living in the valley, while strawberry employment and wages do not. Immigrant families, moreover, are typically large and contain multiple wage earners who can assemble a sizable annual income by sharing resources. A preferred arrangement is to place the household head in year-round employment while the spouse and other family members find occasional part-time jobs weeding and thinning vegetable crops and perhaps harvesting strawberries in the spring and summer. An immigrant family who cannot place one or more workers in year-round or near year-round jobs, in contrast, 10 plastic plant pots must deploy all its available workers, including children, during the short but intense strawberry harvest to amass sufficient income to carry them over into the next employment season. Valley immigrants only rarely leave the area to seek employment elsewhere during both expected and unexpected periods of high unemployment and underemployment but rely on unemployment insurance and occasional odd jobs to tie them over. Immigrant families are not only large, but nearly 45 percent of them are extended; that is, they are made up of one nuclear family and at least one arrimado -usually a live-in relative. Many extended groups include two or more nuclear families with arrimados who share income, expenses, and household responsibilities. About one-third of the settled families, particularly those who arrived with the first waves, own their homes, while one-half of the families who rent have lived at the same address for at least three years. It is, therefore, a relatively stable population. Newcomers, those who arrived with the last wave, experience a more precarious existence and, as a result, frequently change domicile. There is, for instance, an observable annual concentration-dispersion cycle which corresponds with periods of high and low employment; that is, in bad times several families will converge, actually crowd, into a shared apartment, dispersing into separate homes as soon as better times return. Immigrant homes, finally, contain a considerable number of “visitors” who are either family and friends from the home community in Mexico or paying boarders. Settled families, in fact, represent a sort of haven for seasonal migrants, especially kin, who receive shelter and assistance while they remain in the valley during their annual trek from Mexico. On the other hand, by letting rooms, converted garages and other home facilities to non-kin during the farm employment peaks, immigrant families earn additional revenue with which to supplement an always insufficient farm income.

Settled immigrant families, in contrast with all other farm workers, lead relatively stable existences in the valley. They, in fact, enjoy a greater degree of employment security and many have set up permanent residences. As such, it would appear that settled families should not pose serious difficulties or obstacles to enumeration efforts. To accept this as a sound conclusion, however, would be a grave mistake. Settled families, to begin, harbor a significant number of unauthorized/undocumented immigrants who need to be protected from detection. Although IRCA amnesty provisions allowed many long-term undocumented immigrants to legalize, it forced many others who did not qualify for any of the programs, who were unable to assemble the required documents, or who just simply did not understand the new law to remain undocumented. IRCA also enticed many regular sojourners who already spent a great part of the year in the Santa Maria Valley to settle there permanently and to subsequently transplant their families from Mexico. Although these recent settlers received authorization to remain in the United States thanks to the Special Agricultural Workers program, the imported dependents have not been authorized. Finally, as indicated above, settled families habitually provide kin with sanctuary during their seasonal sojourn from Mexico to the valley and, hence, add to the growing number of undocumented aliens to be found in their midst. Because many of the undocumented are close kin, immigrant families will not readily or voluntarily reveal their presence to anyone; they are, rather, quite determined to shield them from detection and possible deportation. It is necessary to note that immigrants’ dogged determination to conceal undocumented relatives, even from innocuous surveyors, increases exponentially as the anti-immigrant sentiment we have witnessed in recent times swells. Local, state, and federal “get tough with immigrants” measures which, among other results, propose to bar children from school, deprive workers from access to basic health services, and rescind citizenship from the children of undocumented parents born in the United States are all unmistakable signs that the risk factor of detection is greater than ever. Cautious suspicion, as a result, is heightened to near paranoia when it is rumored that, among others, teachers, doctors, social workers, and “good” citizens at large will be asked, if not required, to report the presence of undocumented aliens to proper government authorities. Finally, because many immigrant families lease parts of their dwellings to non-kin sojourners, violating in the process local housing ordinances and rental agreements, they are not inclined to reveal or report their presence to anyone. Moreover, they can become particularly apprehensive about this matter because boarders provide an income that probably goes unreported to the Internal Revenue Service.Easy to confuse with the growing ranks of settled immigrant families described above are some 3,000 workers who, although they appear to have settled permanently in the Santa Maria Valley, really have not. That is, though they display evidence of settlement by having both consumers and producers living in stable and well-organized domiciles in the valley, they also continue to maintain a principal place of residence in the Mexican home community. Some actually own and maintain two homes, one in Mexico and the other in the Santa Maria Valley. Members of these families move back and forth between the two homes incessantly, some at regular intervals following, for example, farm employment cycles and school schedules, and others seemingly at random.

The specifics of the organism’s capabilities and the environmental features that structure resource selection opportunities are constraints. In the diet breadth model constraints include things like the size of the forager, the hunting and gathering technology used, and the distribution and caloric value of the targeted resources. Constraints are all of the elements of the situation that are taken for granted , in order to focus analysis on one set of effects. The measure we use to assess costs and benefits is known as the currency. While the currency might be any feature of a resource that gives it value, foraging theorists typically assume that food energy is the most important attribute. After oxygen and water, mammals require metabolic energy in large amounts on a nearly continuous basis. The omnivorous diet of most hunter-gatherers makes it likely that meeting one’s need for energy entails meeting the needs for other nutrients. This may be more problematic with agriculturalists. The kcal currency is expressed as an efficiency, the net acquisition rate of energy. Where energy is not limiting or is less limiting than some other factor—e.g., protein—then that can be used as the currency. For instance, we know that some forms of energy, especially those from large or dangerous game animals, are more prestigious than others , suggesting that not all kilocalories are equal. Prestige might enter into the currency in some cases. Behavioral ecologists generally emphasize secondary currencies like kcals or mating success because they are more tractable than the primary neo-Darwinian measure of reproductive fitness . The final feature of models is the goal. A deterministic foraging model likely would have the goal of maximizing energy capture while foraging. A risk-sensitive model would emphasize the goal of avoiding harmful shortfalls of energy. Behavioral ecology models of food transfers in a social group might stress the evolutionarily stable equilibrium of distribution tactics.

The polygyny threshold model for mating tactics would emphasize the goal of reproductive success. Different goals usually imply different methods: simple optimization analysis for energy maximization; stochastic models for risk minimization; game theory for frequency dependent behaviors, like intragroup transfers, best indoor plant pots that result in evolutionarily stable strategies. The optimization assumption ties together constraints, currency, goal, and the costs and benefits of the alternative set. For instance, given constraints of resource densities and values, and their associated costs and benefits, we predict that organisms will select the alternative that provides them the highest available net acquisition rate of energy. As noted earlier, even when there is no particular shortage of foodstuffs, efficient foraging frees time for alternative activities and lessens exposure to risks associated with foraging. While we don’t expect the organism always to engage in the optimal behavior, models based on this assumption have proven to be robust when compared to ethnographic and archaeological datasets .The diet breadth or resource selection model is one of the oldest and most commonly used , particularly by archaeologists . It is sometimes called the encounter contingent model because it focuses on the decision to pursue or not to pursue, to harvest or not harvest, a resource once it is encountered. The decision entails an immediate opportunity cost comparison: pursue the encountered resource, or continue searching with the expectation of locating more valuable resources to pursue. If the net return to is greater than , even after allowing for additional search time, then the optimizing forager will elect to pass by the encountered resource, and will continue to do so no matter how frequently this type of resource is encountered. The general solution to this trade-off is devised as follows: each of k potential resources is ranked in descending order by its net return rate for the post-encounter work to obtain it. This represents a resource’s net profitability with respect to pursuit, harvest, and handling costs.

The derivation of the best-choice diet begins with the most profitable resource , and, stepwise, adds resource types, continuing until the first resource with a profitability less than the overall foraging efficiency of the diet that does not include it . Resources ranked are excluded because to pursue them would impose an unacceptable opportunity cost: a lower return rate for time spent pursuing them relative to the expected benefits from ignoring them in favor of both searching for and pursuing more profitable types. Think of picking up change in tall grass: if there are enough silver dollars and quarters the income-minded gleaner will ignore the dimes, nickles, and pennies, no matter how frequently they are encountered. Notice that the DBM also entails a marginal decision: It asks, is the profitability of the next ranked item above or below the marginal value of foraging for all resources ranked above it? Creative use of this or any foraging model entails thought experiments of the form: how will an optimizing forager respond to a change in independent variable x. Predicted responses are confined to options with the alternative set, but the independent variable x might be any change in the environment or the behavioral capacities of the forager that affects the primary model variables: resource encounter rates and profitability. For instance, resource depression,environmental change, and other factors which diminish encounter rates with highly ranked resources will increase search costs, lower overall foraging efficiency, and as a result, may cause the diet breadth of a forager to expand to include items of lower rank. One or more items that previously ranked below that boundary may now lie above it, making these resources worth pursing when encountered. The converse is also true. Sufficiently large increases in the density of highly ranked resources should lead to exclusion from the diet of low ranked items. A seasonal elevation of fat content, or adoption of a technology that makes its pursuit, harvest or processing more efficient or any factor that raises the profitability of a particular resource will elevate its ranking, perhaps enough to move into the best-choice diet. It may, in fact, displace resource items previously consumed. Winterhalder and Goland provide an extended list of factors that might operate through encounter rate and pursuit and handling costs to change resource selectivity. The diet breadth model also implies that, under a given set of conditions, resources within the optimal diet are always pursued when encountered; those outside the optimal diet will always be ignored. There are no “partial preferences,” such as “take this organism 50% of the time it is encountered.” Likewise, the decision to include a lower-ranked item is not based on its abundance, but on the abundances of resources of higher rank. Think of the small change mentioned earlier.In the diet breadth model, we envision a resource that is harvested as a unit with a fixed value .

By contrast, a patch is a resource or set of resources which is harvested at a diminishing rate, either because it is depleted in such a way that makes continued harvesting more difficult; the densest and ripest berries are picked first, blueberry container size or because the continuing presence of the forager disperses or increases the wariness of remaining resource opportunities as in the second or third shot at a dispersing flock of grouse. Patches can be ranked like resources, by their profitability upon encounter. As a first approximation, the same predictions apply. However, predictions are somewhat less clear for the selection of patches than for resources, because a definitive prediction about patch choice is interdependent with a decision about patch residence time, the focus of the next model.If a resource patch—which we envision as a small area of relatively homogeneous resource opportunities, separated by some travel distance from other such locales—is harvested at a diminishing rate of return, it is obvious to ask when the forager should abandon its efforts and attempt to find a fresh opportunity. By moving on, he or she will incur the cost of finding a new patch, but upon locating it, will be rewarded with a higher rate of return, at least for a while. The marginal value theorem postulates a decline in return rates for time spent in the patch, usually approximated by a negative exponential curve. The optimizing solution specifies that the forager will leave the present patch when the rate of return there has dropped to the average foraging rate. The average foraging rate encompasses the full set of patches being harvested and the travel costs associated with movement among them. To stay longer incurs unfavorable opportunity costs because higher returns were available elsewhere. To stay a shorter duration is also sub-optimal, because rates of return are, on average, higher when compared to the costs of moving on to another resource patch. In this model, short travel times are associated with short patch residence ; long travel times with longer residence times. The forager optimizing his or her patch residence time rarely will completely deplete a patch;the resources left behind are significant for the recovery of the patch. Finally, the value of harvested patches, upon departure, is the same. The inter-dependence between the two patch related models should now be more apparent. Predictions about patch residence time depend on patch choice; reciprocally, predictions about patch choice depend on residence time. Use of one of these models must assume the other; Stephens and Krebs give a more detailed discussion of this model.The ideal free distribution is a model of habitat choice . The distinction between patches and habitats is one of scale: patches are isolated areas of homogenous resource opportunities on a scale such that a forager may encounter several to several dozen in a daily foraging expedition. Habitats are similarly defined by their aggregate resource base, but at a regional scale. As suggested by their greater relative size, habitats also invoke somewhat different questions, such as where to establish and when to move settlements, and when to relocate by migration. Generally, we ask how populations will distribute themselves with respect to major landscape features like habitats. In the ideal free distribution, the quality of a habitat depends on resource abundance and the density of the population inhabiting and using it. The model assumes that the initial settlers pick the best habitat, say “A.” Further immigration and population growth in habitat A reduce the availability of resources and the quality of the habitat drops for everyone. Crowding, depletion of resources, and competition are possible reasons for this. The marginal quality of habitat A eventually will drop to that of the second-ranked, but yet unsettled, habitat B. If each individual in the population seeks the best habitat opportunity, further growth or immigration will be apportioned between habitats A and B such that their marginal value to residents is equalized. Lower ranked habitats will be occupied in a similar manner. This model predicts that habitats will be occupied in their rank order, that human densities at equilibrium will be proportional to the natural quality of their resources, and that the suitability of all occupied habitats will be the same at equilibrium. In the IFD the creative element resides in imaging how various socioenvironmental settings might affect the shape of the curves representing the impact of settlement density on habitat quality. For instance, it is possible that settlement at low densities actually increases the suitability of a habitat. Forest clearing by the newcomers leading to secondary growth might increase the density of game available to them and to emigrants. This is known as the Allee effect. Likewise, some habitats may be quickly affected by settlement, generating a sharply declining curve of suitability as population densities increase, whereas others may be much more resilient. If immigrants to a habitat successfully defend a territory there, then newly arriving individuals will more quickly be displaced to lower ranked habitats, a variant known as the ideal despotic distribution .Many foragers, human and nonhuman, locate at a dry rock shelter, potable water, or a valuable or dense food source or other particularly critical resource—e.g., an attractive habitation site, or perhaps at a location central to a dispersed array of required resources—and then forage in a radial pattern from that site. Central place foraging models address this circumstance. They assume that a forager leaving such a home base must travel a certain distance through unproductive habitat to reach productive foraging zones.

Species interactions have received less attention in global change biology than individual species’ responses. In large part, this is because long-term data on species interactions spanning the period of intense anthropogenic environmental change are rare. For example, first flower dates of Japanese cherry blossoms have been recorded in diaries since the ninth century, but we have no equivalent long-term records of cherry tree pollination, leaf microbial communities, or disease incidence. Data describing species interactions are laborious to collect and, in many cases, require technology, such as electron microscopy or DNA sequencing, that was not available until recent years. The lack of long-term data inhibits assessment of how species interactions are impacted by global change and limits our ability to determine how these effects mediate individual species’ distributions, abundances, and ecologies. Variation in species responses to global change has generated concern that interactions which were tightly coupled historically might become decoupled owing to phenological asynchronies. Phenological asynchrony arises when interacting species respond differently to global change—for example, if earlier flowering as a consequence of global warming is not matched by earlier pollinator emergence. Recent meta-analyses have suggested that phenological sensitivity to climate change differs among trophic levels, with lower trophic levels advancing more than higher trophic levels. In one well-documented example, great tit reproduction did not advance in sync with peak food availability for young, leading to potential fitness costs. Similarchanges in interactions between trophic levels may happen as a consequence of other differential responses to global change, such as spatial mismatches between species whose ranges expand poleward or upward in elevation to different extents.

While predictions for phenological and spatial asynchronies are clear, empirical data are sparse, square plant pots and there is still no consensus on whether asynchrony is common or rare, or which traits regulate when asynchronies arise. In the absence of long-term observational data, global change biologists increasingly mine museum collections to investigate how species interactions have shifted over time. Diverse types of data are available only in natural history collections, and they could therefore have wide applicability in global change biology. While natural history specimens are not collected systematically—and their use in ecological and evolutionary research can present challenges—they represent time-series data across much of the globe, span the tree of life, and may be able to fill gaps in species interactions data. Importantly, a large proportion of specimens were collected prior to the intensification of anthropogenic change and therefore may serve as baselines for studying consequences of, for example, invasive species spread, pollution and habitat alteration. Here, we explore the potential for museum specimens to provide insights into interactions between insect herbivores and their host plants. Insects have been eating plants for nearly 400 million years, and these interactions have given rise to much of macroscopic diversity. Herbivores co-evolved with plants, tracking plant speciation or defensive profiles and are frequently specialized. Over the past 12 000 years or so, humans have altered these relationships by domesticating plants and moving them beyond their natural ranges, spraying pesticides, building cities, and changing the global climate. Effects of these global changes on herbivores and their host plants is of critical importance to ecosystem functioning and the provision of ecosystem services. Insect damage—‘herbivory’—drives ecosystem processes, including decomposition and primary productivity. Herbivory also influences ecosystem properties that are of direct importance to people, including food production and tree cover, which are linked to human physical and mental health. In general, warming is expected to increase insect herbivore abundance where insects are living below their thermal optima.

While most insects in temperate and boreal climates probably occupy niches well below their thermal optima—and thus may benefit from warming—warming may cause temperatures to exceed insect thermal optima in areas that are already relatively warm, including the tropics. Insect fitness is not, however, a simple function of mean annual temperature, especially at the local scale. For example, many species have thermoregulatory behaviours that decouple body and air temperatures. In some cases, warming may also have negative effects on insect fitness by reducing snowpack or disrupting diapause. Furthermore, and contrary to the prediction that warming should increase temperate insect herbivore abundance, recent evidence suggests that insect biomass has declined precipitously in Germany since the 1980s. The extent of these declines across space and the mechanism driving them remain unknown, as does whether these declines have occurred in other continents, where comparable long-term insect data were not recorded. While shifts in the global climate will undoubtedly shape species interactions, the local drivers of global change may have complex and nonlinear impacts. Urbanization is a more localized form of global change that is accelerating, with important consequences for plant –insect interactions, and has thus attracted much recent attention in ecology and evolution research. Most people now live in urban areas for the first time in history, and the proportion of the world human population living in urban areas continues to grow. Impacts of urbanization on plant –herbivore interactions could thus have increasing consequence for society via its effects on urban greenery and agriculture. However, the key mechanisms driving insect and plant responses to urbanization remain debated because: urban development, like climate change, has multiple, concurrent effects that are difficult to tease apart experimentally, and we lack long term observational data to determine effects of urbanization over time. Despite these data challenges, studies in the past few decades consistently show that urban development can have profound impacts on plants and insect herbivores. The suite of competing predictions of how insects might respond to global change, and the multitude of mechanisms linking insect herbivore abundance and fitness to herbivory, makes predicting changes in insect damage to plants difficult in the absence of long-term data on historical responses.

Further, herbivory data for assessing competing hypotheses are currently sparse and thus ill-suited for making projections about herbivory change into the future. According to a recent compilation of studies, most short-term herbivory studies include just one year of data , focus on forest plants , are biased toward the northern hemisphere , and record only chewing damage, which represents a fraction of the damage types made by insects. Though short-term studies over space have highlighted that disturbance can have profound effects on plants and herbivores, only few studies focus on disturbed habitats, including cities and farms, areas where plant –herbivore relationships are likely to affect human well being. Here, we propose that biological collections could contribute data that would allow us to test major hypotheses on how diverse plant –herbivore relationships respond to global change. In contrast to observational or experimental studies of insect herbivory, data from museum collections span decades or sometimes centuries, include diverse growth forms and taxa from across the globe, and capture multiple types of herbivore damage. We focus on hypotheses that may be particularly well served by the 380 million vascular pressed plant specimens—herbarium specimens—and the more than 500 million insect herbivore specimens held in museums worldwide that are increasingly available online in the form of images and metadata. In general, we focus on above ground, not below ground herbivory, because intact roots required for assessing below ground herbivory are rarely available on herbarium specimens. Digitization of insect specimens has lagged behind plants owing to the difficulty of capturing three-dimensional specimens and the information from their labels. However, enormous efforts to digitize both plant and insect specimens are underway. Digital collections are also increasingly aggregated in online databases, e.g. the Chinese Virtual Herbarium , LepNet , Symbiota , GBIF , and iDigBio .These databases facilitate ‘big’ data analysis, but are equally as important in helping focus data collection efforts when physical specimens need to be examined. As we discuss below, these specimens can provide a wealth of ecological data that is difficult or impossible to collect using more traditional approaches. In the following sections, we demonstrate how natural history collections may provide unique insights into changing plant –insect herbivore interactions. We focus on species shifts in time and space as a response to recent anthropogenic climate change, and impacts of urbanization, representing one facet of habitat transformation, which is a major driver of current global change. In subsequent sections, we discuss how collections can also reveal species’ rapid adaptive responses to recent global changes, an application that may be particularly consequential for agriculture. Finally, plastic potting pots we review the challenges of natural history collections as sources of long-term data and suggest approaches to some of these challenges, with the goal of removing barriers that have prevented collections from becoming a standard source of data for twenty-first century ecology.Phenology—the seasonal timing of life-history events such as flowering and leaf-out in plants—is both a response to and an indicator of global change. Phenological models, such as the Spring Indices, allow us to map with increasing accuracy the transition from winter to spring across the northern hemisphere. These models integrate daily climate variables from meteorological records to predict day of year of first leaf and first bloom. However, the Spring Indices are calibrated using an extensive network of phenological observations on a single cloned lilac cultivar and two honeysuckle cultivars across the temperate United States .

While meta analyses reveal a consistent fingerprint of climate change on plant phenology, they also reveal large interspecific variation in plant responses. Thus, responses to climate change remain poorly characterized for the majority of plant species. The vast wealth of vouchers within herbaria greatly expand the spatial, taxonomic, and temporal extent of phenological observations and, as a consequence, the inference we can draw across climate space, even for species for which phenology has been documented in long-term observations. Animals are also shifting their phenology with climate change; many species are migrating sooner, advancing seasonal breeding times, and insects are emerging earlier. Natural history collections have been valuable in demonstrating how animal species respond to climate warming. Thanks to the biases of early Victorian naturalists and their attractiveness to contemporary collectors, the Lepidoptera— butterflies and moths, which in their immature stages are herbivorous—have been collected more comprehensively than many other groups and are thus the subject of a large proportion of collections research on animals. Butterfly collections document occurrences of species in time and space and, importantly, the seasonal timing of butterfly flight. Using data from approximately 48 000 collection records of Canadian butterflies, Kharouba et al. were able to show that timing of flight season predictably responded to temperature, and that species with early flight seasons and low dispersal ability appear most sensitive. However, in one recent study, Brooks et al. collected data from 83 500 specimens of British butterflies spanning100 years of climate change which suggested that early flying species might be approaching the limits of their phenological advancement. If advances in butterfly phenology are slowing but their host plants continue to leaf-out and flower earlier, we might observe phenological asynchrony between them. In collections research the potential for phenological synchrony between plants and their pollinators has tended to attract most attention, and collections data have been less frequently used to explore plant–herbivore interactions. However, the few studies that have considered phenological asynchronies between plants and insect herbivores demonstrate the potential for collections to inform such analyses. For example, Kharouba et al. showed that flowering time was more sensitive to temperature than the timing of nectar-feeding butterfly flight, suggesting that caterpillars or adult butterflies of these species might become phenologically mismatched with their host plants if warming continues. While collections data can be extensive for particular taxonomic groups, it is nonetheless rare for collections to capture temporally and spatially matching data on interacting species, such as on both butterflies and their host plants. However, herbarium collections can offer data on phenological sensitivity of plant species and, indirectly, data on their herbivores as captured by the amount of leaf area removed by herbivory. Herbaria may thus offer a unique opportunity to explore how shifts in plant phenology have affected herbivory since the onset of climate change. In figure 2, we outline some possible scenarios describing how warming could affect plant and insect phenology, and how these responses might translate to changes in herbivore damage to plants. For simplicity, we focus on spring phenology and specialized herbivores, though for plants that are commonly eaten primarily by generalists, we could derive an additional set of predictions. Additional factors, such as herbivore developmental plasticity, host plant nutritional quality , relationships with natural enemies, and differential responses among herbivores of a single host plant, might add complexity to the predictions described in figure 2, but could be placed within this general framework.

To compare whether the proportion of occupied nests differed with nest strata or the diversity of nest entrance sizes available, we used generalized linear mixed models with ‘glmer’ in the ‘lme4’ package in R . We compared two models. In the first, we included nest strata , nest size treatment , and the interaction between the two as fixed factors, the vegetation complexity index as a covariate, and site as a random factor. In the second, we removed the VCI. To select the best model, we used the Akaike’s Information Criterion computed with the ‘mass’ package . For both models, we used the binomial error distribution with the logit link. Instead of using the proportion data directly, we used the ‘cbind’ function with number of nests occupied and number of nests that were not occupied as input variables. To examine whether species richness differed with nest strata or the diversity of nest sizes available, we used two methods. First, we compared the mean species richness of ants occupying nests on a plant with GLMMs with ‘glmer’ in the ‘lme4’ package in R . We compared two models. In the first, we included nest strata , nest size treatment , and the interaction between the two as fixed factors, the vegetation complexity index as a covariate, and site as a random factor. In the second, we removed the VCI. To select the best model, we used the Akaike’s Information Criterion computed with the ‘mass’ package . For both models, we used a Poisson error distribution with the log link. Second, we created sample-based species accumulation curves, scaled to the number of individuals, to compare richness in coffee plants vs. trees and diverse vs. uniform nest size treatment plants with EstimateS . We used the number of ant colonies encountered instead of the number of individuals, growing blackberries in containers as ants are social organisms and better captured by number of colonies .

We examined curves for both observed species richness and plotted 95% confidence intervals to statistically compare species richness between treatments. To compare whether community composition of ants differed with strata and with nest size treatment, we used two methods. We used non-metric multidimensional scaling and analysis of similarities in PAST to visually and statistically compare species composition of the ants occupying nests in coffee vs. shade trees and in uniform vs. diverse nest treatments. The ANOSIM compares the mean distance within groups to the mean distance between groups, and can statistically determine separation in species composition between the plots in different treatment groups. For the NMDS and ANOSIM we used the Bray-Curtis similarity index as the similarity measure. Finally, we examined whether common ant species more frequently colonized nests of a certain entrance size or vegetation strata. To compare if nests with certain entrance sizes were more frequently occupied by ants we used an ANOVA followed by a Tukey’s test to compare the mean proportion of nests of each entrance size that were occupied. We only used data from the diverse treatment plants to calculate differences in nest colonization. To compare if certain ant species more frequently occupied certain nest sizes or strata we performed Chi-squared analysis which is recommended for categorical data and tests the likelihood that an observed distribution is due to chance .Ecological studies strive to understand local and regional factors that influence community assembly and species coexistence . Some factors important in for assembly of arboreal twig-nesting ants include presence of a canopy dominant species and resource access through canopy connectivity . Previous studies have found that diversity of nesting resources influences the colonization process of leaf-litter twig-nesting ants and of tropical arboreal ants and that the abundance of nesting resources may impact colonization of arboreal twig-nesting ants .

The study of assembly in ant communities in a spatial context reveals that species sorting, by which different species specialize in a particular habitat, and mass effects, in which species disperse from less to more suitable habitats, are likely important for common and rare species, respectively, in agroecosystems — habitats embedded in landscape mosaics were local communities interact through dispersal . Our study is novel in that we examined colonization in a managed ecosystem looking at two factors and their importance in colonization. In this study, we suggest that nesting resource utilization, specifically different frequencies of occupation of specific nest entrance sizes and specific nesting strata are important drivers of community assembly. Overall, l we found that nesting strata and the diversity of nest entrance sizes did not significantly influence the proportion of occupied artificial nests. Thus, ants use newly available cavities for colonization and nesting resources are somewhat limiting for the community of twig-nesting ants in the habitat studied. In comparison to our study, Powell et al. found that total nest occupancy was higher with higher nest cavity diversity in the Brazilian savanna . It is possible that such distinct results derive from differences in overall nest availability, differences in vegetation and differences in the abundance of particular genera . However, it is important to consider that the near-saturation found in the present study could be a result of adding only one cavity of each size per plant, which could mean that there were not enough nests to be colonized, once the “preferred” sizes were used on every plant —hence not available for other species to occupy. Differences in nest saturation and the proportion of nest occupation between both studies could be due to differences in the number of cavities per size used in the experiment. Thus, it is difficult to say that differences in nest limitation are due to the agroecological context, since previous studies in coffee plantations have found that the community of twig nesting ants are limited by nesting resources , as are ants in natural ecosystems . In addition, differences in occupation dynamics of artificial nests during the colonization phase could potentially change with length of the study. A clear contrast is that the present study lasted three months, a third of the previous study, this difference in time could potentially influence competition for “preferred” cavities during colonization, as these are available for a longer period of time during the colony life cycle. Very little information is available about the reproductive phenology of arboreal twig-nesting ants. The evidence collected from our nests indicates that all common species were producing larvae and pupae, and that most species nests did contain alate males. Two of the common species collected from nests in the present study do experience queen flights during this time period , but information is lacking for the other species. Thus, timing of nest placement may have affected the colonization processes, but it is important to note that many twig-nesting species expand by colony budding, and not only nuptial flights. Changes in the occupation dynamics —i.e. proportion of occupied nests, changes in diversity and species interactions—through time, could be the focus of future studies. Even though diversity of nest entrance sizes did not influence the percentage of occupation overall, frequency of occupation of nests by ants did differ for particular sizes. Higher occupancy was found in middle sizes , these results are similar to Powell et al. in which middle sizes were the most frequently occupied.

The specificity in the use of particular sizes is important in two ways: first, the evolution of ecological specialization underlies the evolution of morphological specialization in ant soldiers, Powell showed that for different species of Cephalotes anincrease in ecological specialization corresponded to a higher head specialization ; in that same study C. persimilis uses cavities that match the size of one soldier’s head and it has also evolved a highly specialized complete headdisc, while less ecologically specialized Cephalotes species, square pot like C. pusilus have evolved a domed-head. Second, such size specialization maximizes individual nest survival and is likely to have a positive effect on overall colony reproduction as shown previously for C. persimilis, which more frequently nests in cavities that fit its head size . On the other hand Cephalotes ants using cavities larger than their soldier’s head, allows them to protect the nest using cooperative blocking . The present study supports the former hypothesis , in that the Cephalotes species present in our study , a domed-headed soldier morphotype, was more frequently found in the largest size , an entrance size much larger than the ant’s head maximum-recorded width . Other Cepahlotes species prefer natural nest sizes between four and up to ten times their head size . If C. basalis shows a similar preference, and if we assume a maximum head size of ~5 mm , than its preferred size might be between the 16 mm2 and 32 mm2 nests offered in this study.Mean species richness was not different in artificial nests on coffee plants and trees, however the diversity of nest entrance sizes increased mean species richness on individual trees and coffee plants. In contrast to a previous study in which diversity of nest cavities did not significantly affect the number of ant species per tree , we did find that providing a diverse array of twig entrance sizes promoted local ant species richness in both coffee shrubs and shade trees. This supports the idea that making a diversity of resources available in both strata supports a more diverse mix of arboreal twig nesting ants. That we found more species richness per tree when providing a higher diversity of nest sizes could indicate that competition for resources might happen more intensively at the local scale, rather than at larger spatial scales. Namely, in a study of leaf-litter twig-nesting ants in shade coffee plantations in Colombia, 80% more species were found when providing a diverse mix of twigs rather than a monospecific collection of twigs showing that diversity of twig-nesting ants is influenced by other aspects of diversity of nesting resources. We found that certain ant species more frequently occupied particular sizes and this may be in part, an explanation for why we found higher species richness on individual plants with a diversity of nest entrance sizes. Armbrecht et al. showed the importance of a diverse mix of twigs for species richness, however the driver in their study was not preference of different ant species for a different species of twigs, but rather an emergent property of a diverse mix of twigs. In our study, we provide evidence that species sorting along a size gradient likely explains the differences observed in mean species richness in uniform vs. diverse treatments. The frequency of occupation differed between sizes for certain ant species, largely following differences in ant head sizes . As small ants can occupy a nest with a wide array of entrance sizes, larger ants can only occupy nests with entrances sizes larger than the workers. Thus providing a wider diversity of nest sizes may allow for greater niche differentiation in the ant community. This outcome might increase the overall richness of the ant community or on individual plants. In our study, larger ants seem to be more size limited than smaller ants, likely because larger ants simply cannot fit into the nests with smaller entrance sizes, and thus are directly constrained by the availability of twigs that fit their body dimensions . In vastly different systems, similar properties operate. For example, in aquatic systems, water temperatures can limit temporal and spatial distribution of certain species as morphological constraints can significantly limit species’ access to suitable habitats . Alternatively, models of exploitative competition have suggested that when two species compete for one limiting resource the result of such competition is determined by the species more capable to attain the lowest equilibrium resource concentration possible, R* . In other words, R* becomes a factor that is the lowest extent to which a certain species can survive in a certain area. Community composition varied between plants with uniform vs. diverse nest entrance sizes, as well as in coffee plants and shade trees. Our results are consistent with previous studies that have investigated ant stratification in the rainforest, where there is a strong partitioning of ant species in the leaf litter, lower vegetation and canopy . Likewise, tropical ant activity is often higher in the canopy than in the litter environment, and species composition differs between the canopy and litter assemblages .

The total run time per sample was 61.67min. Electron ionization was performed with a source temperature of 230o C and the quadrupole at 150o C. The wine samples were measured using synchronous scan and selected ion monitoring . The mass spectrometer scanned from m/z 40 to 300. Compounds were detected using between two and six selected ions. Data was analyzed using MassHunter Qualitative Analysis software . After normalization with 2-undecanone internal standard, results were expressed as peak areas. Compounds were tentatively identified in the mass spectrometry spectrum of the peaks and confirmed by comparison to the National Institute of Standards and Technology database . The ions used SIM for each compound and retention times were reported previously by . The odor activity value thresholds were obtained from a selected review of published literature of young red wines and were used in comparing the monitored compounds . Meteorological data collection and climactic conditions at the experimental site for the 2020 and 2021 growing seasons are described in detail by Marigliano et al. . Briefly, there were 1762.7°C growing degree days accumulated in 2020 compared to 1572.3°C GDDs accumulated in 2021, with similar GDD accumulation from April to June in both years. Compared to the 10-year average , the 2020 growing season accumulated more growing degree days by 1 October. The 2021 growing season was a cooler year with less accumulated GDD than the 10-year average. The total precipitation at the experimental site from 1 March 2020 to 30 September 2020 was 84.1mm, a notable 100.5mm less precipitation than the 10-year average for the experimental site. Drought conditions continued into the 2021 water year, growing blueberries in containers with 66.9 mm of precipitation between 1 March 2021 and 30 September 2021.

Precipitation only occurred in March and April 2021 and was negligible in the following months. Given the severe drought conditions in both experimental years, precipitation had a negligible effect on plant water status in control and shaded treatments with 25% ETc replacement, as demonstrated by no significant effects on stem water potential integrals between control and shaded treatments in either experimental year .Grapes resulting from field treatments were vinified under the same conditions in both years. In 2020 alcohol content was the highest in D1 and D4 wines , while alcohol content and residual sugar concentration was lowest in C0 in 2020. All shade film wines contained more alcohol and residual sugar than C0. In 2021, alcohol content and residual sugar concentration was unaffected across all wines. In 2020, pH was only decreased in D3 wines. In 2021, C0 wines had the lowest pH compared wines from shaded grapes. Among the shaded treatments, D4 and D5 wines had higher pH compared to D1 and D3 wines. In 2020, titratable acidity only increased in D3 wines compared to C0, D1 and D5 wines. C0, D1, D4 and D5 wines were indistinguishable in titratable acidity. While C0 had one of the lowest values for TA in 2020, C0 wines in 2021 had one of the highest TA values, along with D3 and D5 wines. The lowest TA value was observed in D4 wines from 2021. Color intensity within the 2020 wines varied considerably, with the D4 having the greatest value for CI . In 2021, D4 again had the highest values for CI, while the remaining wines were statistically not different from each other. Hue decreased only in D3 wines during the 2020 vintage, while there was no effect of shade films of wine hue during the 2021 vintage . The trend for the percentage of polymeric anthocyanins was consistent in both vintages. D1 and D4 had the highest percentage of polymeric anthocyanins, while D5, D3and C0 wines had less . In 2020, D1 and D4 wines had higher TPI values compared to C0 and D3 wines. In 2021, TPI of wines was not affected by shade films except for D4. 3.3 Wine flavonoid content and profile Wine anthocyanin profiles were separated into glucosides, 3-acetylated and coumarylated anthocyanins .

The total free anthocyanin concentration was the lowest in C0 wines compared to shade film treatments in 2020. Concentrations of 3-glucosides and 3-acteylated glucosides increased for all anthocyanins under shading treatments compared to C0, except for peonidin 3-acetyl-glucoside and cyanidin 3-glucoside in which shading treatments had no effect. The composition of coumarylated 3’4’5’-hydroxylated anthocyanin modifications was largely impacted by shading, with the largest concentrations detected in C0, D1 and D5 wines. Overall, the ratio of di- to tri-hydroxylated anthocyanins was the largest in C0 wines and the lowest in D5. Conversely in 2021, total free anthocyanin concentrations were the highest in D4, C0, and D1 wines. Anthocyanin modifications due to shading treatments were more varied in 2021 compared to 2020. Overall, wines from D4 had the most 3-glucosides and 3-acetylated glucosides, while C0 and D5 consistently had less. Coumarylated anthocyanin concentrations were reduced in D3 and D5 wines compared to C0 wines. This was not consistent with the concentrations observed in 2020. Likewise, there was no statistically significant effect on the anthocyanin hydroxylation ratio in 2021 wines, while shading had an impact on anthocyanin hydroxylation in wines in 2020. Nine flavonol compounds were monitored in wines using HPLC . For all monitored flavonol compounds except myricetin-3-glucuronide, C0 wines consistently had the highest concentrations in 2020 compared to shaded wines, with D4 and D5 wines following in flavonol concentration. Subsequently, C0 also had the highest wine flavonol concentration when calculated as total flavonols in 2020. A similar trend occurred in 2021. C0 wines from 2021 also contained greater concentrations of each flavonol compared to shaded treatments, as well as total flavonol concentration.The wine aroma profiles from the 2020 and 2021 vintages were analyzed with and 29 volatile compounds were identified and categorized into their respective compound classes . The aromas profiles of wines depended highly on vintage, resulting in distinct aroma profiles.

Generally, in 2020, total higher alcohols were unaffected by shade treatments, except for isoamyl alcohol and benzyl alcohol. Wines produced from shaded fruit had similar concentrations of isoamyl alcohol while the C0 had the lowest isoamyl alcohol concentration. Benzyl alcohol concentrations were reduced in D3 and D5 wines compared to C0, D1 and D4 wines. In 2021, shading treatments did not impact the concentration of higher alcohols in the resulting wines except for benzyl alcohol, which increased in 2021 D3 wines compared to all other treatments. Acetate esters and fatty acid ethyl esters showed varied effects in wines due to shading in 2020. C0 and D5 had the lowest ethyl acetate concentrations compared to the other shade treatments. Likewise, isoamyl acetate was reduced in C0, D4 and D5 wines compared to D1 and D3 wines. Among the shade film treatments , ethyl hexanoate and ethyl octanoate concentrations were comparable between D1 and D5 wines and were greater than concentrations found in D3 wines. C0 and D5 wines were indistinguishable in ethyl butyrate, ethyl-2-methylbutyrate and ethyl valerate in 2020, with D1 and D3 wines having the highest concentrations of each these ester compounds. Isobutyric acid increased in D4 in 2020. In 2021, there were no significant impacts of shading on acetate esters, fatty acid ethyl esters, ethyl butyrate, ethyl-2-methylbutyrate or ethyl valerate. The effect of shade films on various terpenes and norisoprenoids was highly dependent on vintage conditions. Alpha-terpinene was highest in D5 wines but was significantly reduced in D1 and D3 wines in 2020. The D4 wines had the most cis-rose-oxide while C0 wines had the least. Linalool concentrations were reduced in C0, D4 and D5 wines. Among the shaded treatments, nerol concentrations were enhanced in D5 wines in 2020, square pots while there was no effect of shading on nerol concentration in 2021. D5 did not differ from the C0 in nerol concentration in 2020. Farnesol in D3 was reduced in 2020 whereas farnesol concentrations were not affected in 2021 wines. Conversely, nerolidol was unaffected by shade films in 2020, whereas significant decreases in nerolidol concentrations were observed in D4 and D5 wines in 2021. It was observed that β-damascenone were elevated in 2020 in C0 wines, yet differences in β- damascenone concentrations were non-significant between shade film treatments. In 2021, only significant differences in β-damascenone concentrations were observed in wines, with C0 wines containing the most β-damascenone and D5 wines containing the least. β-ionone concentrations were not statistically significant between all treatments in 2020 and 2021. To determine the effects of partial solar shading on wine chemistry, flavonoid composition, and aromatic profiles of wines we conducted a principal components analysis for both vintages . In 2020, PCA indicated that PC1 accounted for 30.8%, and PC2 accounted for 22.1% of the total variance. The C0 treatments clustered together, separately from the partial solar shading treatments. The separation along PC1 was explained by the ratio of di- to tri-hydroxylated anthocyanins in wines, norisoprenoids and flavonols, as well as lower CI, alcohol content and TPI. The separation along PC2 was explained by TA, pH, terpenes and the percentage of polymeric anthocyanins in wine samples. In 2021, PCA indicated PC1 accounted for 29.9%, and PC2 accounted for 22.2% of the total variance. The C0 treatments again separated from shade film treatments, but less so than in 2020. The separation in PC1 was again explained by the ratio of di- to tri-hydroxylated anthocyanins, along with the total glucosides, total methylated anthocyanins, and total anthocyanins. The separation of C0 was along PC2 and thus was associated with higher concentrations of flavonols, terpenes, norisoprenoids, and polymeric anthocyanins in wine. We analyzed the relationships further between the variables monitored with a correlation analysis in wines . In 2020, CI in wines had the strongest positive correlation with TPI and acids .

Alcohol percentage and ketones were also positively correlated to TPI and acids, although less so than CI. Ketones also were very strongly positively correlated with higher alcohols, while higher alcohols were less strongly correlated to acids. Conversely, flavonols were strongly negatively correlated with acetate esters and other esters in wines. Norisporenoids and pH were less negatively correlated to acetate esters. Fatty acid ethyl esters particularly showed to be negatively correlated with TA. In 2021, the strongest positive correlations in wines were between total anthocyanins and total glucosides and total methylated anthocyanins . Total coumarylated anthocyanins were significantly and positively correlated to total anthocyanins, methylated anthocyanins, and total glucosides. Strong negative correlations were found between hue and ester compounds including fatty acid ethyl esters and acetate esters. A strong negative correlation existed between the ration of di- to tri-hydroxylated anthocyanins and total acetylated anthocyanins. Lastly, total higher alcohols and pH were strongly negatively correlated with each other. In hot viticulture regions, there is a desire to reduce excessive alcohol content in wines due to marketability and taxation concerns. Numerous studies have demonstrated that partial solar radiation exclusion is an effective method for reducing the amount of ethanol in wines by reducing TSS in shaded clusters . However, in the present study, C0 wines consistently had the lowest alcohol content and the lowest concentration of residual sugars in 2020 compared to shaded fruit, despite grapes at harvest having similar TSS values across the treatments . This may be due to the composition of sugars in the grape berry being affected by excessive cluster temperatures in C0 fruit. Sepúlveda and Kliewer showed that heat stress at 40°C post-veraison decreases glucose and fructose in the grape berry. During heat wave events post-veraison, cluster temperatures in C0 reached a maximum temperature of 58°C, exceeding the point at which glucose and fructose content is altered . Additionally, the production of non-fermentable sugars such as arabinose, raffinose and xylose are known to be present in the grape berry . Genes involved in the production of these sugars have been shown to be upregulated under heat stress conditions in grapevine . While the grape berry is 95-99% glucose and fructose at harvest, these non-fermentable sugars are included in the metric of total soluble solids . As a result, while TSS was unaffected by shade films , the proportion of fermentable to nonfermentable sugars may be impacted, thus leading to 2020 C0 wines with reduced alcohol content. This difference in alcohol content between 2021 wines was not observed most likely due to the 2021 growing season being cooler with less GDDs than 2020 .

Currently, Sangiovese is also the cultivar with the highest number of clones registered in the Italian National Catalogue of Grapevine Cultivars showing 130 clones in 2020. Despite its global distribution and importance, there are a limited number of international studies on Sangiovese grapes and wines. The most substantial scientific works were presented at theInternational Symposium of Sangiovese between 2000 and 2004 in Italy. Some of these studies showed the influence of regionality and terroir on the flavor profile of Sangiovese wine. Recent research has focused on the relationship between Sangiovese clones’ grape quality and their oenological properties and polyphenol composition of Sangiovese wines and the mouthfeel perception. A first study about the chemical characterization and comparison of Sangiovese wines from California and Italy was recently reported. The findings demonstrated that the California Sangiovese wines have common characteristics with the Italian wines, particularly related to some volatile grape-derived compounds. These components can be associated with the varietal character of Sangiovese in both regions as the wines in each region retain a common set of characteristics, particularly for the varietal volatiles that originated from grape. Typical characterization of wines includes relationship between sensory profile and volatile compounds, polyphenols, and elements. A much smaller number of studies have compared the chemical and sensory profiles of wines from multiple countries, including Malbec from Argentina and California, red wines from Australia and China, and Sauvignon blanc wines from France, New Zealand, Spain, South Africa, and the United States. Regional typicality is an important concept for the wine industry as it not only delineates geographic areas but also comprises wines with recognizable sensory characteristics and composition. Characterizing regional differences in wines requires studying the intrinsic quality as its inherent physical-chemical characteristics. Moreover, perceived quality is rated by experts, critics, and consumers, gallon pot which altogether defines a profile that describes common regional characteristics among wines. The concept of perceived quality is even more critical when the studies are related to typical wine such as a Protect Designation of Origin . In fact, in a PDO context or when describing a wine belonging to a particular region and produced with a recognizable grape variety, the intrinsic quality of wines could be summarized by the typicality assessment.

Typicality is defined as the characteristics of a product from a terroir, meaning that the product is representative of its terroir, with terroir defined by two dimensions such as the environmental factors and the variety, cultivation, and wine making practices. Among them, the effect of interactions between the natural environment and the vegetal material is known to be a major driver of wine typicality and quality. Thus, typicality can be defined as a set of properties of belonging and distinction. Considering the absence of defects as a pre-requisite, some authors proposed that the intrinsic quality is the resultant of three different profiles: an eligibility profile, whose parameters are common to all wines ; an identity profile , whose parameters are related to the grape variety and the terroir; a style profile related to the brand, expression of the kind of wine making. The eligibility profile can change over time without affecting the identity of the wine, while the identity profile cannot change because it represents the distinct characteristics that define the typicality of a wine. Finally, the style profile can chance overtime as function of the market or the winery brand needs, without altering the identity profile of the wine. It is important to highlight that even in countries with consolidated protected designation of origin and protected geographical indication systems, a scientific approach of typicality still represents a challenge in terms of concept and sensory methodologies. Since Sangiovese is one of the most wide-spread Italian red grapes and a very terroir-linked variety, it is important to study this grape cultivar on a broader scale in order to answer some key questions such as the relationship between the chemical differences, in terms of eligibility and identity profiles, of the wines from different countries and the sensory profiles of the relevant wines,and how do Tuscan experts perceive the typicality of the Sangiovese wines from California and Italy, and which sensory descriptors best describe the wines. The purpose of this study was to evaluate the intrinsic and perceived quality of Sangiovese wines from Italy and California, defining both similarities among wines from the same region of origin and the main differences between wines from Italy and California.

Twenty commercial wines from the 2017 harvest were collected to be representative of both regions . The selection of the wines was made according to the study of the 2016 vintage by the same authors. All of the wines used in this study were sourced from commercial producers, were required to be 100% Sangiovese, and were not oak barrel aged. All wines selected did not show off-flavors. A minimum of 6 bottles were received for each wine sample. As the wines were made solely from Sangiovese grapes under commercial wine making conditions, the differences in composition should reflect the regional styles. In California, the wines were chosen from the following American Viticultural Areas : Central Coast, North Coast and Inland Valley region. The AVAs incorporate the following counties/regions: Amador County, Napa Valley, Santa Ynez Valley, Paso Robles, Saint Joaquin valley and Alameda County. In Italy, the wines were chosen from Tuscany representing the wine areas of Chianti Classico, Chianti, and Montalcino. As all wines used in this study were commercial products; there was no control over the viticultural or wine making practices, and all participating wineries were asked for a “best representation of Sangiovese. The eligibility chemical characteristics were represented by standard parameters, color indices, and polyphenol composition; the identity chemical characteristics were represented by the volatile fractions of the wines. The style requirement was represented by the chemical variables related to wine aging . The standard parameters were measured with FT-IR analyses according to OIV/OENO Resolution 390/2010 and carried out by means of a FOSS WineScan . Color intensity and hue were measured according to the method of Glories and the total phenols index as described by Ribereau-Gayon. The ultraviolet-visible absorbance of the samples was measured on an Agilent spectrophotometer Cary 8454 UV–visible diode array detector, and the software used was UV–Visible ChemStation . Milli-Q water was used as a reference . The polyphenol contents of the wines was determined according to Girardello et al. methods using an Agilent 1260 Infinity HPLC equipped with an autosampler, temperature-controlled column compartment, and a diode array detector.

The polyphenol composition of the wines is shown in Table S1 . Free volatile compounds were determined according to the method developed previously by HS-SPME GCMS. The analytical system for the determination was a Gerstel MPS2 autosampler mounted to an Agilent 6890N gas chromatograph paired with an Agilent 5975 mass-selective detector constituted the analytical system for the GC-MS analysis. The software used was MSD ChemStation . The volatile composition of the wines is shown in Table S2 . All the wine samples were analyzed in triplicates for all chemical parameters.The descriptive sensory analysis panel took place in the J. Lohr Sensory Room at the Department of Viticulture and Enology, University of California Davis. The panel consisted of 11 judges. We recruited the participants from students, staff, and friends of UC Davis based on availability and interest. The protocol was exempt by the internal regulatory board . The panel leader trained the panelists in six 60-min training sessions. In the first sessions, the panelists were presented with a range of Sangiovese wines and invited to describe them, generating descriptors and idea of standards. In the subsequent sessions, gallon nursery pot the judges were provided of subset of samples and reference standards until they reached the consensus about the attributes and the score sheet sequencing. The references were prepared from food and household products commonly available in the supermarket. The level of training of the panelists was checked by an individual evaluation of a subset of the samples and the analysis of the data. The eligibility sensory profile was described by the following 6 attributes: Sour, Sweet, Bitter, Viscous, Astringent, and Hot/Burning. The identity profile was defined by the following 13 aromatic attributes: Citrus, Floral, Black pepper, Dried fruit, Barnyard, Dark Fruit, Rubber, Cherry, Alcohol, Honey, Red berries, Earthy, and Bell pepper in-mouth flavor. One attribute described the style requirement, namely Oak odor and Oak in-mouth flavor. The wine samples were served at room temperature in black glasses covered with plastic lids. Each sample contained a constant volume of 40 mL of wine. Wines were tasted blind, coded with randomized three-digit numbers, and served twice during the training period. At the end of the training period, the panel had consensus on 14 aromas, 3 taste and 3 mouthfeel descriptors for the wines . The panelists had the opportunity to familiarize themselves with the data entry system FIZZ network for collecting the attribute ratings. Before each evaluation, panelists took an aroma quiz on the consent aromas, and on the first data collection day, panelists tasted the taste and mouthfeel standards. The experimental design consisted of 12 wines served across judges in a balanced block design in triplicate. We labeled the wine samples with different 3-digit codes for each panelist. Panelists evaluated all wines in a total of 6 sessions, where one session consisted of 6 samples. Panelists rated the wines in individual, ventilated, and light isolating tasting booths under white light. For attribute ratings, we used an unstructured 15-cm line scale anchored by the wording “not present” to “very intense”, except for viscous, where the wines were rated from “thin” to “thick”. Judges were required to spit all the wine samples and wait 30 s between samples to clean their palates with water and unsalted crackers. At the end of each session, panelists had snacks, and after the study, panelists received a gift card. All the training and evaluation sessions were performed in about two months .Eleven Italian experts , working with Sangiovese wine, with extensive experience with the different expression of Sangiovese wine produced in most important wine producing Italian areas, were involved in a sensory evaluation session in which three tests were performed: Napping® test and the typicality and color assessments. The same 12 wine samples submitted to the descriptive analysis were evaluated except for the sample 12C that was damaged during shipment from California to Italy. These sensory evaluations took place in the wine sensory laboratory at the Department DAGRI, University of Florence . The expert panelists were informed at the beginning of the study that the wines were all Sangiovese of the 2017 vintage. They were then instructed to assess the color of the samples presented under a white light, in glasses covered with plastic lids, labeled with capital letters, from A to M. The panelists were instructed as follows: “Imagine that you wanted to explain to someone what a Sangiovese wine color is. To explain, you can suggest to this person to evaluate a wine. For each wine presented, you must answer the following question: Do you think that this wine is a good example or a bad example of what a Sangiovese wine color is?” The score of each sample was assigned on a categorical scale, from 1 to 7, anchored at left to “very bad color” and on the right to “excellent color”. After this, judges proceeded to the Napping and typicality assessments. The Napping is a specific variant of Projective Mapping, a method originally proposed for applied sensory studies by Risvik et al. to describe overall differences among samples. In both the Napping and typicality sessions, panelists were presented with the 11 wine samples plus one replicate. The evaluations were performed in isolated, ventilated sensory booths under red lights, to eliminate bias attributed to color differences. Each wine sample consisted of 25 mL of wine at room temperature presented, in clear 190 mL standard tasting glasses covered with plastic lids, and labeled with different random three-digit codes for each panelist and session. For both tests , a complete randomized and balanced experimental design was followed for the presentation order. In the Napping session, the 12 samples were simultaneously presented to the panelists, who were then required to project them on a two-dimensional space , in a way that reflected their perceived sample differences, i.e., by placing samples perceived as similar close to each other, and samples perceived to be more different further apart.

To gain statistical evidence of miRNA differential expression driven by the environment and/or genotype, we made pairwise comparisons, keeping constant the developmental stage, and evaluating the miRNA modulation among vineyards or between cultivars . The analyses reveal that some miRNAs are differentially expressed between the two genotypes grown in the same environment, but also that a number of miRNAs are modulated by the environment. In particular the number of differentially expressed miRNAs is higher in ripened berries , while no miRNAs are differentially expressed at bunch closure stage . In details, 14 reads are differentially expressed at pea size stage, in at least one comparison, corresponding to 6 distinct miRNA families; 27 reads are modulated at 19 ◦Brix stage, corresponding to 12 miRNA families and 35 reads are differentially expressed in berries at harvest, corresponding to 12 miRNA families. It is worth noting that 4 of the 6 families modulated in the berries at pea size, are still present among the miRNAs differentially expressed in the berries sampled at 19 ◦Brix and at harvest , even though not always in the same comparisons. Some of the modulated miRNAs, both novel and known are intriguingly connected to berry development and secondary metabolism, even though most of the modulated families are still uncharacterized, or with targets not clearly involved in berry ripening and development, and deserve further studies to fully understand their biological roles. Using high throughput sequencing coupled with robust bioinformatics pipelines we analyzed small RNAs derived from the berries of Cabernet Sauvignon and Sangiovese, grown sideby-side in three vineyards, representative of different grapevine cultivation areas in Italy . The size distribution profiles of our libraries were in general consistent with previous reports in berry grapevine, black plastic pots for plants where the 21-nt class was more abundant than the 24-nt class .

Our analysis revealed dynamic features of the regulatory network mediated by miRNAs and other small RNAs, at the basis of genotype-environment interactions. Plants evolved a series of pathways that generate small RNAs of different sizes with dedicated functions . Although the various small RNA classes have been intensively studied, we are still far from understanding how many small RNA pathways exist, and how they are connected . Additionally, new classes of small non-coding RNAs continue to be discovered and many studies demonstrate a substantial redundancy and cross-talk between known small RNA pathways . Estimating the exact percentage of the plant genome covered by small RNA-generating loci still remains a challenge. By applying static cluster analysis, we investigated small RNA abundances across the genome, identifying 4408 small RNAs producing hotspots. We analyzed their expression in different cultivars, environments and developmental stages, highlighting that the majority of the considered small RNA producing regions was modulated in different conditions. This suggests a strong influence of small RNAs in the response to environment in grapevine berries. Only 462 small RNA-generating loci, corresponding to about 10% of the total, were expressed in all the analyzed libraries, possibly involved in essential biological pathways. Comparing the two cultivars, we observed, with few exceptions, that Cabernet Sauvignon berries have a higher number of expressed sRNA-generating loci than Sangiovese berries when collected in the same conditions . Considering the fact that small RNAs are implicated in the regulation of gene expression in several processes , the higher number of small RNAs expressed in Cabernet Sauvignon compared to Sangiovese berries may reflect a buffering effect of small RNAs influencing grapevine response to diverse growing environments. We believe that these characteristics may have contributed to the wide diffusion of Cabernet Sauvignon, allowing its wide cultivation in almost all wine producing countries. This is not the case for Sangiovese whose cultivation is more restricted.

It is worth noting that Sangiovese is considered a very unsettled grapevine cultivar , showing a wide range of variability in response to year, clone and bunch exposure . Differently, Cabernet Sauvignon is a cultivars showing less inter-annual differences in terms, for example, of concentration of secondary metabolites . To better evaluate varietal differences in response to the environment, we calculated the CS/SG ratio for the small RNA producing hotspots in the three vineyards. An interesting example is found in green berries sampled in Riccione. A region on chromosome 4 showed a 390-fold change in the small RNA abundance, when comparing Cabernet vs. Sangiovese . Most of the reads produced in this region are 21 nt long and are also phased in intervals of 21 nt from both strands, typical of a phased locus . The gene in this locus, also known as VvRD22g, encodes a BURP domaincontaining protein, involved in an ABA-mediated abiotic stress response, which persists still after long periods of stress . The small RNAs profile suggests that the locus is regulated by phased siRNAs similarly to the mechanisms already described for PPR, NB-LRR, and MYB gene families . This is a clear example of GxE interactions since the BURP domain gene modulates phased siRNAs production in the two cultivars only when grown in Riccione. When removing the threshold of minimum cluster abundance set to 5 HNA, in the CS/SG ratio, a high number of clusters with fold change greater than 50 was found, where one of the libraries has 0 HNA and the other any number greater than 30 HNA. This fact suggests a very strong modulation of the expression of small RNAs between the two cultivars, which is more or less pronounced depending on the vineyard where the berries were cultivated. A similar situation was observed comparing the expression level of small RNAs between reciprocal hybrids of Solanum lycopersicum and S. pimpinellifolium . The ripening process of grapevine berries is highly affected by the environment and we observed the impact of the environment on the ripening process in the expression of small RNAs.

The most relevant observation is that Riccione is very peculiar in relation to the activation of sRNA hotspots, as indicated by the high number of Riccionespecific clusters and by the extreme modification it induces in the CS/SG ratio : in Riccione in fact this ratio decreases in green berries and increases in ripened berries, and this is not observed in any other vineyard; in addition to this the already discussed example of BURP domain gene, is observed in Riccione, as well. Riccione is the most diverse environment when compared to Montalcino and Bolgheri. Riccione is located at the Adriatic coast and has a temperate sub-littoral climate, while Montalcino and Bolgheri are both located in Tuscany with typically Mediterranean climate. Moreover, both cultivars show a peculiar profile of small RNA loci during berries ripening, in Riccione. The expression of small RNA loci in Cabernet Sauvignon berries drastically changed during development, especially when collected in Riccione , not only in the number of active loci but also in the different genic or intergenic disposition: ripened berries have a 2.6-fold increase in small RNA loci active in genic regions. Differently, when Sangiovese is grown in Riccione, there is a very high number of small RNA loci active in green berries, mainly associated to transposable elements that remains almost stable during development although the proportion of intergenic loci is reduced. Sangiovese berries collected in Montalcino show a 2.5- fold increase of small RNA producing loci during development. Differences during berry development between the cultivars may explain their different behavior in different environments, and the characteristics of each vineyard may favor one or other variety according to their demands. For example, Sangiovese needs a long growing season with sufficient warmth to fully ripen . Consequently, drainage pot cooler environments will require a reprograming of Sangiovese gene expression in order to achieve ripening. Other factors such as composition of soil, level of humidity, photoperiod and density of cultivation may be exerting the same influence on the ripening of the berries triggering the activation of different small RNA loci. Applying a conservative pipeline to the analysis of our 48 small RNA libraries, we recognized 89 known and annotated grapevine miRNAs. In addition, when compared to previous reports in grapevine we identified 7 completely novel miRNAs plus 26 homologous to other plant species, but novel to grapevine. This is a remarkable number considering the stringency of our pipeline and that our study is based only on four developmental stages of berries. The outline of miRNA accumulation across samples is different from that of sRNA-producing loci. While the expression of sRNA-generating regions allows distinguishing very well between ripened and green berries and also between cultivars , the accumulation of miRNAs shows a clear distinction only between ripened and green berries, and when the berries were green, we observe a further dichotomy separating the two cultivars and the two green developmental stages. The same pattern of miRNA accumulation among green and ripened berries of grapevine was observed when we described the miRNA expression atlas of Vitis vinifera . Comparing the distribution of miRNAs expressed throughout our samples, we found a set of 39 miRNAs ubiquitous or nearly ubiquitous to all the libraries, and very few miRNAs specific of a cultivar, vineyard or developmental stage.

All these 39 miRNAs belong to known vvi-miRNA families. With few exceptions, the same set of miRNAs was also found expressed in all the small RNA libraries constructed with different tissues of the grapevine cv. Corvina , where the population of expressed miRNAs appears highly variable apart from a well-defined group of miRNAs, probably related to the basal metabolism. These findings are also consistent with previous report in grapevine where a small number of known tissue-specific miRNAs was described . Considering the ripening process as shown in the heat maps , and the correlation dendrogram, it is clear that most miRNAs are modulated during the developmental process. For some miRNA families, we observed the same peculiar patterns of miRNA accumulation, previously described in the grapevine miRNA atlas , e.g., an increase of accumulation toward ripening for miR156 f/g/i, and a decrease for miR166c/e, miR172d, miR319, and miR396a/b, but this is not the main focus of our paper. To establish genotype and environmental influence on miRNA modulation, we performed a statistical analysis that revealed a number of miRNAs differentially expressed. Being aware of the fact that we had only two biological replicates, we applied the exact test as implemented in the EdgeR package. This test has been recently judged a very robust tool that can be used in experiments similar to our, because of its low false positive rate and relative high true positive ratein the presence of a fold change higher than 4 . Considering berries at the same developmental stages, we compared Sangiovese vs. Cabernet Sauvignon in a given vineyard and Montalcino vs. Bolgheri, Montalcino vs. Riccione, and Bolgheri vs. Riccione keeping the cultivar fixed. In total we performed 9 pairwise comparisons for each developmental stage. In general, we observed that berries at 19 ◦Brix and at harvest show a higher number of differentially expressed miRNAs. The most interesting examples are represented by two novel miRNAs, whose predicted targets are related to the biosynthesis and accumulation of secondary metabolites, which are of crucial importance in grapevine berries, since its quality depends mainly on its metabolites . The candidate grapem1191 is differentially expressed in Sangiovese between Riccione and Bolgheri and was predicted to target the transparent-testa 12 gene that encodes a multidrug secondary transporter-like protein involved in the vacuolar accumulation of the flavonoid proanthocyanidin in different species including grapevine . Also, in grapevine some studies provide evidences that the intracellular transport of acylated anthocyanins is catalyzed by a MATE transporter . The grape-m1355 seems to be involved in four different pathways, all related to secondary metabolites. It is differentially expressed in Montalcino between the two varieties and was predicted to target a cinnamoyl reductase-like protein , which is part of the of the polyphenol biosynthetic pathway ; a cinnamyl alcohol dehydrogenase involved in the lignin biosynthesis ; a phenylacetaldehyde reductase , which catalyzes, in tomato, the last step in the synthesis of the volatile 2-phenylethanol, important for the aroma and flavor of many foods ; and different bifunctional dihydroflavonol 4-reductases . DFR catalyzes the first step in the conversion of dihydroflavonols to anthocyanins and are responsible for the production of colored anthocyanins .

Water use efficiency predictions are further complicated by the results of combination studies of elevated temperature, reduced soil water availability, and elevated CO2, which reveal synergistic effects. In an open top chamber study, combining temperature and CO2 did not result in gs being significantly reduced, contrary to results of elevated CO2 alone . When latent heat is trapped, overheating subsequently decreases the activity of RUBISCO activase, for most plants at temperatures higher than 37°C , and in grapevine between 35-40°C, varying by species . The elevated CO2 and temperature treatments showed an increase in transpiration , and the effects of drought were only temporarily delayed . Temperature and elevated CO2 had an additive effect on plant leaf area for multiple grapevine clones , highlighting that overall higher leaf area without increased WUE could be detrimental for heat stressed vines. Measurements of predawn water potential were more negative in vines at elevated CO2, indicating the demand for soil water availability of vines with increased productivity . Notedly, the production of fine roots was positively impacted by an elevated CO2 treatment, which would theoretically increase water absorption of water available . There remain inconsistent predictions of the effects of elevated CO2 on grapevine whole plant water use efficiency, which seem to be contingent upon other factors such as soil water availability, temperature, and variety of grapevine. With the evidence from these studies of elevated CO2 and combination studies of soil water availability and temperature, grapevines most likely will not benefit from a long-term increase in photosynthesis under elevated CO2. The lack of soil water available and biological temperature thresholds for RUBISCO will limit the gains in photosynthesis, pot with drainage holes and more likely the vines will struggle to release latent heat as temperatures rise.

Grapevine phenology is categorized into four life cycle stages of periodic development: budburst, flowering, veraison, and maturation. The grapevine phenological cycle is a two-year process; bud formation occurs in the first year which develop into shoots in the second year. Therefore, clusters are significantly impacted by the previous year’s climate . For grapevine grown at elevated CO2, advances in phenology compound significantly over seasons . This is likely the result of stored carbon photosynthate from the productive previous year. As a result, it can take several years to observe the effects of elevated CO2 on grapevine phenology , which leads to the question of: “To what extent does elevated CO2 impact the timing of phenological stages over the long-term?” Studies of Arabidopsis, another C3 flowering plant, provide insight to the mechanisms of phenological changes observed in grapevine. Excess carbohydrates may act similarly to phytohormones to delay the upregulation of genes involved in flowering time, as well as cell wall invertases in the meristem that down regulate photosynthesis under treatments of elevated CO2, which leads to earlier flowering . For grapevine, it is possible that excess photosynthate could trigger early flowering through the transfer of carbohydrates from leaves. One of the most robust findings to support this hypothesis is that growth under elevated CO2 results in increased carbohydrate reserves in plants . The sugars produced by photosynthesis contribute only a fraction of the source of carbon needed for rapid growth and development from budbreak to flowering and sugar accumulation in berries at veraison, the remaining needed for these growth spurts is mobilized from long-term storage of total nonstructural carbohydrates in trunks and roots . Over several growing seasons, storage of carbohydrates in the trunk will be impacted by elevated CO2 and could therefore contribute to shifts in phenology.

In a greenhouse study of fruiting cuttings where sugar accumulation in berries was measured, elevated CO2 increased the rate of ripening correlated with the photosynthetic rate . The effect of elevated CO2 on phenology was greater than the treatment of temperature elevated by 4°C . Therefore, an increase in total nonstructural carbohydrates could be a driver of advances in phenology long term, on its own, as well as with concomitant increases in growing season temperatures. Carbohydrate reserves regulate the growth and differentiation of flowers, which only occurs after the grapevine shoot is resource independent from the rest of the vine . These findings suggest that with an increase in carbon reserves stored as starch in roots, trunks and canes, second season shoots may grow faster and achieve independence earlier in the growing season. This could contribute to early flowering as a result of lifted competition for resources between vegetative and reproductive growth. In contrast, long-term studies in grapevine decreasing the leaf to fruit ratios decreased essential reserves of the TNC in the roots . The well-known viticultural technique of strategic leaf removal has been shown to delay maturation, highlighting the importance of carbon availability for phenological development . While the mechanism for phenological shifts in grapevine grown under elevated CO2 is under-studied, these shifts have been quantified using FACE experiments. The combination of elevated CO2 and temperature in OTC caused an advance in flowering time by three days and veraison by two weeks . The impact of elevated CO2 on phenological timing is greatest during the period between fruit set to veraison and this impact increases when combined with a temperature treatment . During fruit set, elevated CO2 treatments with and without temperature treatments increased total soluble solids , as well as decreased anthocyanins and malic acid concentration, which would contribute to an earlier veraison and harvest . However, the impact of high temperature may have a greater impact on this phenological period .

Grapevines vulnerable to frost damage will suffer from early budburst, with subsequent losses in yield . One consequence of increased shoot vigor at elevated CO2 is the expected increase in bud fertility, which will likely increase the number of flowers per vine . Changes in cluster density and phenological timing impact the carefully articulated annual harvest. Unbalanced sugar/acid ratios resulting from early harvest decrease the quality of grapes and wine produced, discussed further in the “Berry and Wine Chemistry” section below . Shifting the lifecycle of grapevine will have a global impact on winegrape production.Fruit composition is a major area of concern for growers and winemakers alike, especially aromatic compounds. The changes in pest interactions, physiology, and timing of veraison in response to elevated CO2 will collectively impact the resulting grape and wine quality . For successful wines, in the grape berry there is a balance of acid and sugar at harvest. Increasing atmospheric carbon available impacts the balance as ripeningadvances and sugar accumulation is accelerated . Flavonoids and anthocyanins are important for the flavor, color, and mouthfeel of wine. The molecular analysis from the original Italian FACE experiments showed increases in total flavonoids, total anthocyanins, and total non-anthocyanin flavonoids in the wine produced with carbon enriched grapes grown at 700 mg/L , which typically would affect the color and mouthfeel of wine. Interestingly, a subsequent experiment using 500 mg/L CO2 open top chambers determined there were significant increases in ethyl 2-methylbutyrate , isoamyl acetate , ethyl hexanoate , ethyl octanoate , butyric acid , and isovaleric acid concentrations and a significant decrease in ethyl acetate concentration in wines produced from enriched CO2 grapes after one year , which contribute to the balance of floral and fruity characteristics in wines . In the second year they found lower methionol , 1-octanol , and 4- ethylguaiacol , and they found higher ethyl lactate and linalool concentrations, large pot with drainage although these changes in berry chemistry did not appear to significantly affect the quality of wine produced . These results agree with early studies led by Bindi et al. that did not find significant effects on the quality of wine produced from grapes grown at elevated CO2 . Although the changes observed in compounds contributing to flavor have been noted as so far insignificant for quality, a major concern for winemakers is the increase in alcohol content resulting from an increase in sugar concentrations in berries, as a result of higher CO2 concentrations . In the past, winemakers have added sugar to the fermentation to increase the final alcohol percentage , depending on legal regulations for winemaking.However, in recent years winemakers have begun removing sugar through processes like reverse osmosis in order to prevent alcohol levels from rising . Overall, elevated CO2 is altering the balance of sugar accumulation, the levels tartaric and malic acids in berries and wine, and the impact on wine quality continues to be investigated . The most recent FACE studies on grapes continue to evaluate the berry chemistry and quality developing over years of exposure to elevated CO2. The VineyardFACE in Germany analyzed must from grapes after pressing and did not find a significant increase in sugar content from conditions of carbon enrichment . The Gonçalves et al. study also concluded that changes in water availability and heat stress could change their predictions in wine quality.

We should expect that with the shifts in phenology and physiological changes to berries, early harvest will impact the quality of grapes in terms of reaching maturation too quickly . Viticulturists could also anticipate altered physiological demands to have long-term impacts on berry quality . In contrast to the ecological pressures discussed above, the rates of some fungal infections may be reduced in elevated CO2 scenarios. With higher carbon allocation to roots, grapevine mycorrhizal colonization may be promoted by elevated CO2 , which has been shown to protect grapevine against the nematode Xiphinema index by stimulating defense gene response . A study of elevated CO2 on several varieties of grapevine seedlings showed a reduced severity of the infection of Xanthomonas campestris pvviticola, a vector of bacterial canker in immature grapevine . This may be the result of lower stomatal conductance ; with stomatal aperture reduced, there is less opportunity for bacteria to invade the leaf pores . Also, researchers recorded a reduced instance and severity of powdery mildew infection in cv Barbera, at elevated CO2 . The Geisenheim VineyardFACE site recorded changes in the bunch architecture but did not see an increase in the frequency of B. cinera, botrytis bunch rot, a necrotrophic fungus, occurrence . Changes in leaf chemistry phenotype, specifically carbon content, , will increase the pressure of grapevine pests in future climates. Increasing available carbon dioxide, without a concomitant increase in nutrient levels in the soil, leads to an increase in C:N ratios in leaves . Insects consume at higher rates when nitrogen has been diluted to meet their nitrogen intake needs and chewing insect pests will generally eat more leaf tissue in elevated carbon dioxide scenarios . Elevated CO2 increased individual survival rates and increased the fecundity of female mealybugs, which eat phloem of grapevine damaging the temporal and perennial plant tissue . The European grapevine moth, Lobesia botrana, is a major problem for European vineyards, affecting both the berries and flowers of grapevines; and has already invaded North and South American vineyards . L. botrana is also responsible for spreading Ochratoxin A-producing Aspergillus fungi, which typically spikes in occurrence during hotter and drier years . At higher temperatures simulating future climate conditions, L. botrana female growth rate and pupal mass increased , while researchers found a down regulation of expression of ethyleneresponsive factors, which suggests grapevines can become more vulnerable to herbivory or abiotic stress under future climate change as these are the major stress and defense response factors . A comprehensive study of soil and elevated CO2 showed the decomposition pathway is altered by the carbon-, nitrogen-, and phosphorus-acquiring enzymes in the soil with a significant increase in nematode density . More than 4,000 plant-parasitic nematodes exist, posing a well-known global issue for grapevine, reducing total crop production by 8.8- 14.6%, and one of the worst threats from the nematode Xiphinema index is GLRV . Under elevated CO2 conditions, if ethylene is suppressed and salicylic acid is increased, it is likely that grapevine will struggle with an increase in pest and disease vectors such as nematodes and fungi . Grapevines largely rely on human intervention for defense against pests and diseases , and this reliance could increase in future climates. Consider the grapevine “immune system” as weakened in terms of chemical defense, but some altered carbon dynamics under elevated CO2 may be beneficial for reducing severity of pest pressure.

The very concept is embedded in the colonial relationship itself, implying as it does that there is some land that is not sacred. Moreover, the federal government did not allow “sacred land” as a legal land-claim defense until the 1970s, and its documentation must meet standards defined by the federal government, a bizarre requirement since the federal courts seldom demonstrate much wisdom in cosmological or religious matters. Thus Indian spiritual connections to the environment are frequently examined and negotiated in light of contemporary residential development, land management activities, and outdoor recreation as well as legislative activities and the outcomes of litigation. Spiritual connections are seldom straightforward however. Stephen Jett suggested that there may be varying degrees of sanctity for Navajo, although he is unclear about whether such a continuum emanates from his own analysis of the situation or from Navajo interpretations. In addition, James Griffith explained in detail the multi-valent possibilities of places where ideas of sacredness held by the Tohono O’Odham, Yaqui, Mexican, and Anglo American peoples intersect. Also, Linea Sundstrom attempted to set the record straight for the Black Hills using archival documents in an ethnohistorical reconstruction identifying what is held sacred in the area, since when, and by whom, including at least seven tribes. The secular popularity of the subject of sacred lands has not come without repercussions. People are dehumanized and cultural complexity trivialized when non-Indian environmentalists furate on indigenous ecological spirituality and activity while ignoring other significant aspects of community and culture. Bruce Willems-Braun makes this point about marginalization of the Nuuchah-nulth of British Columbia, square pot who often have been denied an active role in debates over wilderness preservation because a perspective on the environment has frequently been imposed on them rather than asserted by them.

Three decades ago Brian Goodey called on geographers to work as researcheradvocates in support of Indian tribes and their economic development. Sincethat time, land use, economic development, and tourism, especially related to gambling, have undergone rapid change in Indian Country. When coordinated with tribal interests, research into these areas generally has been viewed positively by tribal governments. There are a number of geographers and their colleagues who are working for tribes directly or as consultants, or are pursuing research on these topics independently. Data problems are a major concern among these researchers, especially difficulties encountered in using census and Bureau of Indian Affairs or Department of Indian Affairs and Northern Development , the Canadian equivalent of the BIA, data for analysis of population and economic and community development. A critical issue in tribal planning is the need to establish a framework for government-to-government relations between tribal and city, county, and state governments when work must be accomplished in a regional context. A major applied research effort on this topic was carried out and summarized by Shirley Solomon, a geographer working with the Northwest Renewable Resource Center in Seattle. This collaboration produced extensive coordination of tribal groups and local governments. One study found that access to health services was severely restricted on the Round Valley Reservation in northern California not only because of its extreme distance from comprehensive medical facilities, but also because trained medical and dental professionals could not be consistently retained. Another found that Montana Indian women were twice as likely as non-Indians to have to travel outside the county to a birthing facility and even more likely to have poor obstetric care anywhere near where they live.

None of this will come as a surprise to readers familiar with rural life, especially life in Indian Country. But geographers are novices to health care planning and are only just beginning to realize their expertise may be of use in examining aspects of health care such as location, access, travel distance, and sense of place. The new multicultural conceptions of health and well-being now beginning to replace standard medical-geography models undoubtedly will encourage more interest in Indian health issues. Federal legislation in the 1980s and 1990s made gambling a potentially significant component of reservation economic development, the impact of which was examined in two edited books and several articles by geographers. The case studies indicate rapid growth in gambling accompanied by some economic benefit accruing to most participating tribes. Long-term stability, increasing competition from other gambling facilities, subsequent social polarization, and the politics of wealth redistribution both inside and outside reservation boundaries are recognized as problems. Regional studies for Connecticut, the Dakotas, New Mexico, and Oklahoma also are included in these publications. The sale of American Indian arts and crafts and the associated appeal of cultural tourism have long played a role in Indian economic life, although the benefits have been distributed unevenly from region to region. In the past, such activities were generally directed and controlled by non-Indians, and the bulk of revenues and proceeds went to non-Indians. While there are some exceptions, this pattern often continues today. Several geographers have studied the consequences of tourism for Native populations and the increased effort to gain local control of tourism facilities and activities. Geographers also have begun applying postcolonial or other social theory to American Indian studies. Generally anglophonic postcolonial studies have emerged from and focus on the British colonial experience; accordingly, postcolonial American Indian research is well represented within Canadian universities, most notably the University of British Columbia. These researchers seek to deconstruct and assess the imprint of a European worldview on the lands, minds, and bodies of Indians. They draw inspiration from postcolonial literature and French intellectuals Henri Lefebvre, Jacques Lacan, Jacques Derrida, and Michel Foucault.

These diverse theoretical currents are brought together in studies of colonial surveillance and control of Indian spaces, the appropriation of such spaces through ethnocentric cartographic or other textual representation, and the various Indian responses to such practices. Nicholas Blomley has employed similar themes, investigating Indian blockades in British Columbia as a mechanism for tribal reappropriation of space, and Robert Galois has attempted a revised empirical overview of historical Kwakiutl settlement free from earlier colonial biases. Explaining the mechanisms of group representation and identity is fundamental in several studies: Berry’s comparative work on waterscapes and representation for Paiute and non-Paiute communities in northern Nevada; Dennis Crow’s inquiry about reservations as “low places”; Deur on the Makah whale hunt revival; Galois on the period of colonial consolidation in British Columbia; Peters’ examination of the apparent conflict between “city person” and “Indian” identities in Canadian cities; and Silvern’s study of treaty-rights conflicts in Wisconsin. Also, the spatial aspects of gender are influential in the way places and people function. Karen Morin examined British women’s constructions of Indians as Others in historic “contact zones” like the railroad depots of the American West, Peters explained the role of Indian females in subverting urban spaces in Canada, and Wishart considered the role and status of women in Pawnee society, and the general place of Indian women as subjects of geographical research. In an unusual link to demographic study, Robert Jackson sifted the evidence of population decline in the US Southwest and developed the thesis that deaths were related not only to disease, but also to place/space destruction and reductions in cohesion, identity, and sense of place. In a similar vein, R. Douglas K. Herman provided insight into changes in Hawai‘ian identity in response to colonization and corresponding shifts in environmental knowledge and language. The question of whether there exists a pan-Indian sensibility about place and space also has been of some interest. In a 1976 interview, N. Scott Momaday proposed and described what he termed a pan-Indian ecological sensibility bound into Indian identity, an ethos distinguished from those of non-Indian North Americans by the presence of what he termed a sense of “reciprocal appropriation.” Then geographers David Stea and Ben Wisner wrote of a panIndian ecological worldview projected outward in solidarity with other indigenous or Fourth World peoples. Since then a few geographers have examined pan-Indianness as an evolving identity crucial to understanding the link between place and action, drainage collection pot and one has written about the men’s movement’s appropriation and wild distortion of elements of this identity.56 Others have shown how Indian identities are materialized in places as disparate as battlefield and massacre sites, cultivated gardens, migration corridors, and interior landscapes of the mind. The Inuit have been of particular interest, as shown in studies attempting to explain their mental landscape representations or “mental maps,” their navigational skills, and their secondary position to environmentalists’ identification with stranded whales and stripped seals. Place names or toponyms are also of longstanding interest to geographers, and another intersection where the work of anthropologists has been influential. Most recently the intimate links among social structure, individual and group identity, and place were illustrated by geographers studying Chinook Jargon, Inupiat, Hawai‘ian, Navajo, and Inuktitut place names. The study of Indian and Inuit maps accelerated during the past ten years and helped revitalize cartography as a discipline with an historically and culturally situated subject matter, and not merely a narrow technical one. A group of writers have examined the interpretations made of Indian or Inuit maps by nineteenth- and twentieth-century explorers and government agents, and the discourses into which these documents entered, including those of contemporary scholarship.60 Map exchanges between Indians or Inuit and Europeans or Euro-North Americans occurred everywhere in North America, but extant examples and thus much of the research effort is concentrated in the continent’s interior plains from Texas to Saskatchewan, and in the Arctic.

These maps are seen as emanating from different assumptions and discourses about the world as a home for humans and non-human others when compared to what Europeans and Euro-North Americans were producing. Indian maps actively disrupted European discourse on geography, history, and identity, and represent one side of what was and still is to some extent an unbridgeable gap in worldviews. The other side, the European and Euro-North American mapping of Indian Country, has also come under scrutiny. This cartography spans the last five hundred years, but geographers have tended to study comparatively recent examples. They have questioned these maps, often finding them ideological weapons serving non-Indian interests rather than the simple and innocent mimetic representations that the general public and their makers imagined them to be. Several others deserve attention because they emanate from Indians or Inuit themselves and represent a new trend of “mapping back” or “counter-mapping” the colonizers. A Zuni Atlas was published because Zuni elders, in their effort to press a land claim, decided it was time to make certain protected geographical information available to the public for the first time. In part this atlas is notable because it reveals some Zuni sacred sites in order to demonstrate land occupancy beyond present reservation boundaries. But it does so using maps drawn at a scale too small for the reader to navigate. Thus the sites were revealed for litigation purposes, but still kept safe from unwanted visitors. The Inuit have been especially active in counter-mapping. First, they created a map series containing their own place names inscribed on Canada’s official topographic maps, then they assembled the Nunavut Atlas, an extensive compilation of wildlife patterns and other environmental data gathered from Inuit elders. These may be viewed both as attempts to overcome disruption of the traditional oral transfer of geographic information from one generation to the next and also as nationalistic outpourings in anticipation of the creation of the new Territory of Nunavut in 1999. Robert Rundstrom has taken note of these developments and their implications in an article and map review. GIS are a completely new technological development within the past two decades but are understood as a natural extension into the digital era of gathering and mapping geographical data. To put it most broadly, GIS are computer systems for the gathering, storage, and manipulation of geographical coordinates and associated statistical data about anything on the earth’s surface, expressions of which can be made in either paper or digital form. They are more than computerized mapping systems because they can transform information in ways uncommon or unknown in traditional map making and they easily link with orbiting satellites and the remotely sensed digital images that satellites transmit. In the past five years, a national American Indian GIS association has developed and is closely linked to the leading corporate manufacturer of GJS software; tribes, therefore, have been very active participants in GIS applications and research. Continued efforts to link the US Census Bureau’s Topologically Integrated Geographic Encoding and Referencing file maps with tribal information has also helped some tribes initiate detailed spatial data analysis of the lands and people administered by tribal government.

The measurement was done using AC current excitations of 0.1 – 20 nA at 0.5 – 5.55 Hz using a DL 1211 current preamplifier, SR560 voltage preamplifier, and SR830 and SR860 lock-in amplifiers. Gate voltages and DC currents are applied, and amplified voltages recorded, with a home built data acquisition system based on AD5760 and AD7734 chips.In crystalline solids, orbital magnetization arises from the Berry curvature of the bands and intrinsic angular momentum of the Bloch electron wave packet. Although the orbital magnetization often contributes—at times substantially—to the net magnetization of ferromagnets, all known ferromagnetism involves partial or full polarization of the electron spin. Theoretically, however, ferromagnetism can also arise through the spontaneous polarization of orbital magnetization without involvement of the electron spin. Recently, hysteretic transport consistent with ferromagnetic order has been observed in heterostructures composed of graphene and hexagonal boron nitride, neither of which are intrinsically magnetic materials. Notably, spin-orbit coupling is thought to be vanishingly small in these systems, effectively precluding a spin-based mechanism. To host purely orbital ferromagnetic order, a system must have a time reversal symmetric electronic degree of freedom separate from the electron spin as well as strong electron-electron interactions. Both are present in graphene heterostructures, where the valley degree of freedom provides degenerate electron species related by time reversal symmetry and a moir´e superlattice can be used to engineer strong interactions. In these materials, a long wavelength moir´e pattern, arising from interlayer coupling between mismatched lattices, vertical towers for strawberries modulates the underlying electronic structure and leads to the emergence of superlattice minibands within a reduced Brillouin zone.

The small Brillouin zone means that low electron densities are sufficient to dope the 2D system to full filling or depletion of the superlattice bands, which can be achieved using experimentally realizable electric fields. For appropriately chosen constituent materials and interlayer rotational alignment, the lowest energy bands can have bandwidths considerably smaller than the native scale of electronelectron interactions, EC ≈ e 2/λM, where λM is the moir´e period and e is the electron’s charge. The dominance of interactions typically manifests experimentally through the appearance of ‘correlated insulators’ at integer electron or hole filling of the moir´e unit cell[13, 19], consistent with interaction-induced breaking of one or more of the spin, valley, or lattice symmetries. Orbital magnets are thought to constitute a subset of these states, in which exchange interactions favor a particular order that breaks time-reversal symmetry by causing the system to polarize into one or more valley projected bands. Remarkably, the large Berry curvature endows the valley projected bands with a finite Chern number, so that valley polarization naturally leads to a quantized anomalous Hall effect at integer band filling. To date, quantum anomalous Hall effects have been observed at band fillings ν = 1 and ν = 3 in various graphene heterostructures, where ν = An corresponds to the number of electrons per unit cell area A with n the carrier density. Although orbital magnetism is generally expected theoretically in twisted bilayer graphene, no direct experimental probes of magnetism have been reported because of the relative scarcity of magnetic samples, their small size, and the low expected magnetization density they are predicted to have.In the absence of significant magnetic disorder ferromagnetic domain walls minimize surface tension. In two dimensions, domain walls are pinned geometrically in devices of finite size with convex internal geometry. As discussed in Fig. 5.15, we observe pinning of domain walls at positions that do not correspond to minimal length internal chords of our device geometry–suggesting that magnetic order couples to structural disorder directly.

This is corroborated by the fact that the observed domain reversals associated with the Barkhausen jumps are consistent over repeated thermal cycles between cryogenic and room temperature. Together, these findings suggest a close analogy to polycrystalline spin ferromagnets, which host ferromagnetic domain walls that are strongly pinned to crystalline grain boundaries ; indeed, these crystalline grains are responsible for Barkhausen noise as it was originally described. Although crystalline defects on the atomic scale are unlikely in tBLG thanks to the high quality of the constituent graphene and hBN layers, the thermodynamic instability of magic angle twisted bilayer graphene makes it highly susceptible to inhomogeneity at scales larger than the moir´e period, as shown in prior spatially resolved studies. For example, the twist angle between the layers as well as their registry to the underlying hBN substrate may all vary spatially, providing potential pinning sites. Moir´e disorder may thus be analogous to crystalline disorder in conventional ferromagnets, which gives rise to Barkhausen noise as it was originally described. A subtler issue raised by our data is the density dependence of magnetic pinning; as shown in Fig. 5.3, Bc does not simply track 1/m across the entire density range, in particular failing to collapse with the rise in m in the Chern magnet gap. This suggests nontrivial dependence of either the pinning potential or the magnetocrystalline anisotropy energy on the realized many body state. Understanding the pinning dynamics is critical for stabilizing magnetism in tBLG and the growing class of related orbital magnets, which includes both moir´e systems as well as more traditional crystalline systems such as rhombohedral graphite. In order to understand the microscopic mechanism behind magnetic grain boundaries in the Chern magnet phase in tBLG/hBN, we used nanoSQUID magnetometry to map the local moir´e superlattice unit cell area, and thus the local twist angle, in this device, using techniques discussed in the literature. This technique involves applying a large magnetic field to the tBLG/hBN device and then using the chiral edge state magnetization of the Landau levels produced by the gap between the moir´e band and the dispersive bands to extract the electron density at which full filling of the moir´e superlattice band occurs .

The strength of this Landau level’s magnetization can be mapped in real space , and the density at which maximum magnetization occurs can be processed into a local twist angle as a function of position . It was noted in that the moir´e superlattice twist angle distribution in tBLG is characterized by slow long length scale variations interspersed with thin wrinkles, across which the local twist angle changes rapidly. These are also present in the sample imaged here . The magnetic grain boundaries we extracted by observing the domain dynamics of the Chern magnet appear to correspond to a subset of these moir´e superlattice wrinkles. It may thus be the case that these wrinkles serve a function in moir´e superlattice magnetism analogous to that of crystalline grain boundaries in more traditional transition metal magnets, pinning magnetic domain walls to structural disorder and producing Barkhausen noise in measurements of macroscopic properties. In tBLG, a set of moir´e subbands is created through rotational misalignment of a pair of identical graphene monolayers. In twisted monolayer-bilayer graphene a set of moir´e subbands is created through rotational misalignment of a graphene monolayer and a graphene bilayer. These systems both support Chern magnets. Both systems are also members of a class of moir´e superlattices known as homobilayers; in these systems, the 2D crystals forming the moir´e superlattice share the same lattice constant, and the moir´e superlattice appears as a result of rotational misalignment, as illustrated in Fig. 5.17A. Homobilayers have many desirable properties; the most important one is that the twist angle can easily be used as a variational parameter for minimizing the bandwidth of the moir´e subbands, container vertical farming producing the so-called ‘magic angle’ tBLG and tMBG systems. Homobilayers do, however, have some undesirable properties. Although local variations in electron density are negligible in these devices, the local filling factor of the moir´e superlattice varies with the moir´e unit cell area, and thus with the relative twist angle. The tBLG moir´e superlattice is shown for two different twist angles in 5.17B-C across the magic angle regime; it is clear that the unit cell area couples strongly to twist angle in this regime, illustrating the sensitivity of these devices to twist angle disorder. The relative twist angle of the two crystals in moir´e superlattice devices is never uniform. Imaging studies have clearly shown that local twist angle variations provide the dominant source of disorder in tBLG . It is hard to exaggerate the significance of this problem to the study of moir´e superlattices. Phenomena discovered in tBLG devices are notoriously difficult to replicate. Orbital magnetism at B = 0 has only been realized in a handful of tBLG devices, and quantization of the anomalous Hall resistance has only been demonstrated in a single tBLG device, in spite of years of sustained effort by several research groups. A mixture of careful device design limiting the active area of devices and the use of local probes has allowed researchers to make many important discoveries while sidestepping the twist angle disorder issue- indeed, some exotic phases are known in tBLG only from a single device, or even from individual scanning probe experiments- but if the field is ever to realize sophisticated devices incorporating these exotic electronic ground states the problem needs to be addressed.There is another way to make a moir´e superlattice. Two different 2D crystals with different lattice constants will form a moir´e superlattice without a relative twist angle; these systems are known as heterobilayers . These systems do not have ‘magic angles’ in the same sense that tBLG and tMBG do, and as a result there is no meaningful sense in which they are flat band systems, but interactions are so strong that they form interaction-driven phases at commensurate filling of the moir´e superlattice anyway. Indeed, many of the interaction-driven insulators these systems support survive to temperatures well above 100 K.

The most important way in which heterobilayers differ from homobilayers, however, is in their insensitivity to twist angle disorder. In the small angle regime, the moir´e unit cell area of a heterobilayer is almost completely independent of twist angle, as illustrated in 5.17E-F. A new intrinsic Chern magnet was discovered in one of these systems, a heterobilayer moir´e superlattice formed through alignment of MoTe2 and WSe2 monolayers. The researchers who discovered this phase measured a well-quantized QAH effect in electronic transport in several devices, demonstrating much better repeatability than was observed in tBLG. The unit cell area as a function of twist angle is plotted for three moir´e superlattices that support Chern insulators in 5.17G, with the magic angle regime highlighted for the homobilayers, demonstrating greatly diminished sensitivity of unit cell area to local twist angle in the heterobilayer AB-MoTe2/WSe2. MoTe2/WSe2 does have its own sources of disorder, but it is now clear that the insensitivity of this system to twist angle disorder has solved the replication issue for Chern magnets in moir´e superlattices. Dozens of MoTe2/WSe2 devices showing well-quantized QAH effects have now been fabricated, and these devices are all considerably larger and more uniform than the singular tBLG device that was shown to support a QAH effect, and was discussed in the previous chapters. The existence of reliable, high-yield fabrication processes for repeatably realizing uniform intrinsic Chern magnets is an important development, and this has opened the door to a wide variety of devices and measurements that would not have been feasible in tBLG/hBN. The basic physics of this electronic phase differs markedly from the systems we have so far discussed, and we will start our discussion of MoTe2/WSe2 by comparing and contrasting it with graphene moir´e superlattices. In tBLG/hBN and its cousins, valley and spin degeneracy and the absence of significant spin-orbit coupling combine to make the moir´e subbands fourfold degenerate. When inversion symmetry is broken the resulting valley subbands can have finite Chern numbers, so that when the system forms a valley ferromagnet a Chern magnet naturally appears. Spin order may be present but is not necessary to realize the Chern magnet; it need not have any meaningful relationship with the valley order, since spin-orbit coupling is absent. MoTe2/WSe2 has strong spin-orbit coupling, and as a result, the spin order is locked to the valley degree of freedom. This manifests most obviously as a reduction of the degeneracy of the moir´e subbands; these are twofold degenerate in MoTe2/WSe2 and all other TMD-based moir´e superlattices.