Body shrinkage due to Arctic warming reduces red knot fitness in tropical wintering range

Mercury contamination is an invisible threat to declining migratory shorebirds along the East Asian-Australasian Flyway

Exposure to pollutants is a potentially crucial but overlooked driver of population declines in shorebirds along the East Asian-Australasian Flyway. We combined knowledge of moult strategy and life history with a standardised sampling protocol to assess mercury (Hg) contamination in 984 individuals across 33 migratory shorebird species on an intercontinental scale. Over one-third of the samples exceeded toxicity benchmarks. Feather Hg was best explained by moulting region, while habitat preference (coastal obligate vs. non-coastal obligate), the proportion of invertebrates in the diet and foraging stratum (foraging mostly on the surface vs. at depth) also contributed, but were less pronounced. Feather Hg was substantially higher in South China (Mai Po and Leizhou), Australia and the Yellow Sea than in temperate and Arctic breeding ranges. Non-coastal obligate species (Tringa genus) frequently encountered in freshwater habitats were at the highest risk. It is important to continue and expand biomonitoring research to assess how other pollutants might impact shorebirds.

Macro-scale relationship between body mass and timing of bird migration

Clarifying migration timing and its link with underlying drivers is fundamental to understanding the evolution of bird migration. However, previous studies have focused mainly on environmental drivers such as the latitudes of seasonal distributions and migration distance, while the effect of intrinsic biological traits remains unclear. Here, we compile a global dataset on the annual cycle of migratory birds obtained by tracking 1531 individuals and 177 populations from 186 species, and investigate how body mass, a key intrinsic biological trait, influenced timings of the annual cycle using Bayesian structural equation models. We find that body mass has a strong direct effect on departure date from non-breeding and breeding sites, and indirect effects on arrival date at breeding and non-breeding sites, mainly through its effects on migration distance and a carry-over effect. Our results suggest that environmental factors strongly affect the timing of spring migration, while body mass affects the timing of both spring and autumn migration. Our study provides a new foundation for future research on the causes of species distribution and movement.

Predicting resilience of migratory birds to environmental change

The pace and scale of environmental change represent major challenges to many organisms. Animals that move long distances, such as migratory birds, are especially vulnerable to change since they need chains of intact habitat along their migratory routes. Estimating the resilience of such species to environmental changes assists in targeting conservation efforts. We developed a migration modeling framework to predict past (1960s), present (2010s), and future (2060s) optimal migration strategies across five shorebird species (Scolopacidae) within the East Asian-Australasian Flyway, which has seen major habitat deterioration and loss over the last century, and compared these predictions to empirical tracks from the present. Our model captured the migration strategies of the five species and identified the changes in migrations needed to respond to habitat deterioration and climate change. Notably, the larger species, with single or few major stopover sites, need to establish new migration routes and strategies, while smaller species can buffer habitat loss by redistributing their stopover areas to novel or less-used sites. Comparing model predictions with empirical tracks also indicates that larger species with the stronger need for adaptations continue to migrate closer to the optimal routes of the past, before habitat deterioration accelerated. Our study not only quantifies the vulnerability of species in the face of global change but also explicitly reveals the extent of adaptations required to sustain their migrations. This modeling framework provides a tool for conservation planning that can accommodate the future needs of migratory species.

Impacts of coprophagic foraging behaviour on the avian gut microbiome

Avian gut microbial communities are complex and play a fundamental role in regulating biological functions within an individual. Although it is well established that diet can influence the structure and composition of the gut microbiota, foraging behaviour may also play a critical, yet unexplored role in shaping the composition, dynamics, and adaptive potential of avian gut microbiota. In this review, we examine the potential influence of coprophagic foraging behaviour on the establishment and adaptability of wild avian gut microbiomes. Coprophagy involves the ingestion of faeces, sourced from either self (autocoprophagy), conspecific animals (allocoprophagy), or heterospecific animals. Much like faecal transplant therapy, coprophagy may (i) support the establishment of the gut microbiota of young precocial species, (ii) directly and indirectly provide nutritional and energetic requirements, and (iii) represent a mechanism by which birds can rapidly adapt the microbiota to changing environments and diets. However, in certain contexts, coprophagy may also pose risks to wild birds, and their microbiomes, through increased exposure to chemical pollutants, pathogenic microbes, and antibiotic-resistant microbes, with deleterious effects on host health and performance. Given the potentially far-reaching consequences of coprophagy for avian microbiomes, and the dearth of literature directly investigating these links, we have developed a predictive framework for directing future research to understand better when and why wild birds engage in distinct types of coprophagy, and the consequences of this foraging behaviour. There is a need for comprehensive investigation into the influence of coprophagy on avian gut microbiotas and its effects on host health and performance throughout ontogeny and across a range of environmental perturbations. Future behavioural studies combined with metagenomic approaches are needed to provide insights into the function of this poorly understood behaviour.

Running the gauntlet; flyway-wide patterns of pollutant exposure in blood of migratory shorebirds

Shorebirds (order Charadriiformes) are among the world's most threatened avian taxa. Within the East Asian-Australasian Flyway (EAAF), a major threat to shorebirds' survival may be the gauntlet of pollution along the flyway. Metals, persistent organic pollutants (POPs), and per-/polyfluoroalkyl substances (PFASs) persist in the environment to the detriment of wildlife. In this study, we analysed element and PFAS concentrations in blood from 142 individuals across six species of Arctic-breeding migratory shorebirds with contrasting population trends, to discern species- and site-specific pollution differences, and determine how pollution correlated with population trends of EAAF shorebirds. Potential within-year pollution variations were investigated by blood-sampling birds at two sites, representing different points in the birds' annual migrations: staging in Taiwan on southward migrations and at non-breeding grounds in Western Australia (WA). Species' pollutant concentrations were compared to established population trends. Concentrations of potentially toxic elements were low in most individuals regardless of species. PFASs (range: <0.001-141 ng/g), Hg (<0.001-9910 ng/g) and Pb (<0.01-1210 ng/g) were higher in Taiwan than in WA (PFAS Taiwan median: 14.5 ng/g, WA median: 3.45 ng/g; Hg Taiwan: 338 ng/g, WA: 23.4 ng/g; Pb Taiwan: 36.8 ng/g, WA: 2.26 ng/g). Meanwhile As (range <0.001-8840 ng/g) and Se (290-47600 ng/g) were higher in WA than Taiwan (As Taiwan median: 500 ng/g, WA median: 1660 ng/g; Se Taiwan: 5490 ng/g, Se WA: 23700 ng/g). Nevertheless, pollutant concentrations in a subset of individuals may exceed sublethal effect thresholds (As, Se and PFASs). Finally, we found no consistent differences in pollution among species and demonstrated no correlation between pollution and population trends, suggesting pollution is likely not a major driver for population declines of EAAF shorebirds. However, ongoing and locally heavy environmental degradation and exposure to other contaminants not investigated here, such as POPs, warrants continued consideration when managing EAAF shorebird populations.

Low migratory connectivity and similar migratory strategies in a shorebird with contrasting wintering population trends in Europe and West Africa

Migratory shorebird populations are declining worldwide, showing an apparent inability to respond to the interplaying challenges emerging along their flyways. Within the East Atlantic Flyway, non-breeding populations show moderate to strong declines in Sub-Saharan Africa, contrasting with stable or increasing trends in Europe. Local factors are insufficient to explain the opposite tendencies and, therefore, investigating migratory strategies and connectivity of these populations may help identifying the drivers of their demography. We followed the migratory journeys of 20 grey plovers (Pluvialis squatarola) from their wintering grounds in Guinea-Bissau (West Africa), Portugal and France (Europe) using tracking devices. Grey plovers wintering in Africa and Europe were found to share breeding grounds at European Russia and Western Siberia, revealing low migratory connectivity in the Eastern Atlantic population. All individuals followed a "skipping" migratory strategy, flying mostly mid-distance bouts, and using an unexpected large network of stopover sites to re-fuel usually for short periods. We identified 66 different stopover sites along the West African, European and Russian/Siberian coasts. All birds stopped at the Wadden Sea in both migratory periods, highlighting the importance of this region and the risk for a potential bottleneck. Low migratory connectivity and similar migratory strategies shared by grey plovers wintering in Europe and West Africa do not support their contrasting population trends.

Predicting the current habitat refugia of Himalayan Musk deer (Moschus chrysogaster) across Nepal

Himalayan Musk deer, Moschus chrysogaster is widely distributed but one of the least studied species in Nepal. In this study, we compiled a total of 429 current presence points of direct observation of the species, pellets droppings, and hoofmarks based on field-based surveys during 2018-2021 and periodic data held by the Department of National Park and Wildlife Conservation. We developed the species distribution model using an ensemble modeling approach. We used a combination of bioclimatic, anthropogenic, topographic, and vegetation-related variables to predict the current suitable habitat for Himalayan Musk deer in Nepal. A total of 16 predictor variables were used for habitat suitability modeling after the multicollinearity test. The study shows that the 6973.76 km2 (5%) area of Nepal is highly suitable and 8387.11 km2 (6%) is moderately suitable for HMD. The distribution of HMD shows mainly by precipitation seasonality, precipitation of the warmest quarter, temperature ranges, distance to water bodies, anthropogenic variables, and land use and land cover change (LULC). The probability of occurrence is less in habitats with low forest cover. The response curves indicate that the probability of occurrence of HMD decreases with an increase in precipitation seasonality and remains constant with an increase in precipitation of the warmest quarter. Thus, the fortune of the species distribution will be limited by anthropogenic factors like poaching, hunting, habitat fragmentation and habitat degradation, and long-term forces of climate change.

Duration and variability of spring green-up mediate population consequences of climate change

Single phenological measures, like the average rate of phenological advancement, may be insufficient to explain how climate change is driving trends in animal populations. Here, we develop a multifactorial concept of spring phenology-including the onset of spring, spring duration, interannual variability, and their temporal changes-as a driver for population dynamics of migratory terrestrial species in seasonal environments. Using this conceptual model, we found that effects of advancing spring phenology on animal populations may be buffered or amplified depending on the duration and interannual variability of spring green-up, and those effects are modified by evolutionary and plastic adaptations of species. Furthermore, we compared our modelling results with empirical data on normalized difference vegetation index-based spring green-up phenology and population trends of 106 European landbird finding similar associations. We conclude how phenological changes are expected to affect migratory bird populations across Europe and identify regions that are particularly prone to suffer population declines.

The incredible shrinking puffin: Decreasing size and increasing proportional bill size of Atlantic puffins nesting at Machias Seal Island

Climate change imposes physiological constraints on organisms particularly through changing thermoregulatory requirements. Bergmann's and Allen's rules suggest that body size and the size of thermoregulatory structures differ between warm and cold locations, where body size decreases with temperature and thermoregulatory structures increase. However, phenotypic plastic responses to malnutrition during development can result in the same patterns while lacking fitness benefits. The Gulf of Maine (GOM), located at the southern end of the Labrador current, is warming faster than most of the world's oceans, and many of the marine species that occupy these waters exist at the southern edge of their distributions including Atlantic puffins (Fratercula arctica; hereafter "puffin"). Monitoring of puffins in the GOM, at Machias Seal Island (MSI), has continued annually since 1995. We asked whether changes in adult puffin body size and the proportional size of bill to body have changed with observed rapid ocean warming. We found that the size of fledgling puffins is negatively related to sea surface temperature anomalies (warm conditions = small fledgers), adult puffin size is related to fledgling size (small fledgers = small adults), and adult puffins have decreased in size in recent years in response to malnutrition during development. We found an increase in the proportional size of bill to wing chord, likely in response to some mix of malnutrition during development and increasing air temperatures. Although studies have assessed clinal variation in seabird morphology with temperature, this is the first study addressing changes in seabird morphology in relation to ocean warming. Our results suggest that puffins nesting in the GOM have morphological plasticity that may help them acclimate to ocean warming.

Arriving late and lean at a stopover site is selected against in a declining migratory bird population

Loss and/or deterioration of refuelling habitats have caused population declines in many migratory bird species but whether this results from unequal mortality among individuals varying in migration traits remains to be shown. Based on 13 years of body mass and size data of great knots (Calidris tenuirostris) at a stopover site of the Yellow Sea, combined with resightings of individuals marked at this stopover site along the East Asian-Australasian Flyway, we assessed year to year changes in annual apparent survival rates, and how apparent survival differed between migration phenotypes (i.e. migration timing and fuel stores). The measurements occurred over a period of habitat loss and/or deterioration in this flyway. We found that the annual apparent survival rates of great knots rapidly declined from 2006 to 2018, late-arriving individuals with small fuel stores exhibiting the lowest apparent survival rate. There was an advancement in mean arrival date and an increase in the mean fuel load of stopping birds over the study period. Our results suggest that late-arriving individuals with small fuel loads were selected against. Thus, habitat loss and/or deterioration at staging sites may cause changes in the composition of migratory phenotypes at the population-level.

Factors influencing mercury exposure in Arctic-breeding shorebirds

Mercury (Hg) pollution remains a concern to Arctic ecosystems, due to long-range transport from southern industrial regions and melting permafrost and glaciers. The objective of this study was to identify intrinsic, extrinsic, and temporal factors influencing Hg concentrations in Arctic-breeding shorebirds and highlight regions and species at greatest risk of Hg exposure. We analyzed 1094 blood and 1384 feather samples from 12 shorebird species breeding at nine sites across the North American Arctic during 2012 and 2013. Blood Hg concentrations, which reflect Hg exposure in the local area in individual shorebirds: 1) ranged from 0.01-3.52 μg/g ww, with an overall mean of 0.30 ± 0.27 μg/g ww; 2) were influenced by species and study site, but not sampling year, with birds sampled near Utqiaġvik, AK, having the highest concentrations; and 3) were influenced by foraging habitat at some sites. Feather Hg concentrations, which reflected Hg exposure from the wintering grounds: 1) ranged from 0.07-12.14 μg/g fw in individuals, with an overall mean of 1.14 ± 1.18 μg/g fw; and 2) were influenced by species and year. Most Arctic-breeding shorebirds had blood and feather Hg concentrations at levels where no adverse effects of exposure were predicted, though some individuals sampled near Utqiaġvik had Hg levels that would be considered of concern. Overall, these data increase our understanding of how Hg is distributed in the various shorebird breeding areas of the Arctic, what factors predispose Arctic-breeding shorebirds to Hg exposure, and lay the foundation for future monitoring efforts.

Generation time and seasonal migration explain variation in spatial population synchrony across European bird species

Spatial population synchrony is common among populations of the same species and is an important predictor of extinction risk. Despite the potential consequences for metapopulation persistence, we still largely lack understanding of what makes one species more likely to be synchronized than another given the same environmental conditions. Generally, environmental conditions in a shared environment or a species' sensitivity to the environment can explain the extent of synchrony. Populations that are closer together experience more similar fluctuations in their environments than those populations that are further apart and are therefore more synchronized. The relative importance of environmental and demographic stochasticity for population dynamics is strongly linked to species' life-history traits, such as pace of life, which may impact population synchrony. For populations that migrate, there may be multiple environmental conditions at different locations driving synchrony. However, the importance of life history and migration tactics in determining patterns of spatial population synchrony have rarely been explored empirically. We therefore hypothesize that increasing generation time, a proxy for pace of life, would decrease spatial population synchrony and that migrants would be less synchronized than resident species. We used population abundance data on breeding birds from four countries to investigate patterns of spatial population synchrony in growth rate and abundance. We calculated the mean spatial population synchrony between log-transformed population growth rates or log-transformed abundances for each species and country separately. We investigated differences in synchrony across generation times in resident (n = 67), short-distance migrant (n = 86) and long-distance migrant (n = 39) bird species. Species with shorter generation times were more synchronized than species with longer generation times. Short-distance migrants were more synchronized than long-distance migrants and resident birds. Our results provide novel empirical links between spatial population synchrony and species traits known to be of key importance for population dynamics, generation time and migration tactics. We show how these different mechanisms can be combined to understand species-specific causes of spatial population synchrony. Understanding these specific drivers of spatial population synchrony is important in the face of increasingly severe threats to biodiversity and could be key for successful future conservation outcomes.

Avian wings can lengthen rather than shorten in response to increased migratory predation danger

Increasing predation danger can select for safety-enhancing modifications to prey morphology. Here, we document the multi-decade wing lengthening of a Pacific flyway migrant, the western sandpiper (Calidris mauri), and contrast this with contemporaneous wing shortening of the closely related semipalmated sandpiper (C. pusilla) on the Atlantic flyway. We measured >12,000 southbound western sandpipers captured from 1978 to 2020 at a major stopover site in British Columbia. Wing length increased at 0.074 mm year-1 (SE = 0.017; p < .0003) for adults, and 0.087 mm year-1 (SE = 0.029; p < .007) for juveniles. These rates are of similarly large magnitude (4%-5% overall), but opposite in direction, to the rate we previously reported for semipalmated sandpiper adults (-0.103 mm year-1). In both species, the change is specific to wings rather than being part of a general body size change. We interpret both trends as responses to the ongoing strong increase of peregrine falcon (Falco peregrinus) populations since the mid-1970s, an important predator encountered by these species in contrasting ways during migration. Western sandpipers and peregrine migrations have temporal and spatial overlap. Longer wings enhance migratory speed and efficiency, enabling western sandpipers to decrease overlap by advancing to safer zones ahead of falcon passage. In contrast, semipalmated sandpipers primarily encounter peregrines as residents at migratory staging sites. Shorter wings improve acceleration and agility, helping migrants to escape attacks. Juvenile western sandpiper wing length also shows a component additive to the lengthening trend, shifting between years at 0.055 mm day-1 with the highly variable snowmelt date, with wings shorter following early springs. On the Pacific flyway, the timing of peregrine southward passage advances with snowmelt, increasing the relative exposure of juveniles to post-migratory resident peregrines. We interpret this annual wing length adjustment as an induced defense, made possible because snowmelt timing is a reliable cue to danger in the upcoming migration.

Egg characteristics vary longitudinally in Arctic shorebirds

Arctic environments are changing rapidly and if we are to understand the resilience of species to future changes, we need to investigate alterations in their life histories. Egg size and egg shape are key life-history traits, reflecting parental investment as well as influencing future reproductive success. Here we focus on egg characteristics in two Arctic shorebirds, the Dunlin (Calidris alpina) and the Temminck's stint (Calidris temminckii). Using egg photos that encompass their full breeding ranges, we show that egg characteristics exhibit significant longitudinal variations, and the variation in the monogamous species (Dunlin) is significantly greater than the polygamous species (Temminck's stint). Our finding is consistent with the recent "disperse-to-mate" hypothesis which asserts that polygamous species disperse further to find mates than monogamous species, and by doing so they create panmictic populations. Taken together, Arctic shorebirds offer excellent opportunities to understand evolutionary patterns in life history traits.

Increases in intraspecific body size variation are common among North American mammals and birds between 1880 and 2020

Many studies have documented the average body size of animals declining over time. Compared to mean body size, less is known about long-term changes in intraspecific trait variation (ITV), which is also important to understanding species' ability to cope with environmental challenges. On the basis of 393,499 specimen records from 380 species collected in North America between 1880 and 2020, we found that body size ITV increased by 9.59% for mammals (n = 302) and 30.67% for birds (n = 78); human-harvested species had higher probability of ITV increase. The observed increasing ITV in many species suggests possible niche expansion and potential buffering effects against downsizing but it risks increased maladaptation to rapidly changing environments. The results demonstrate that trait mean and variance do not necessarily respond in similar ways to anthropogenic pressures and both should be considered.

Immunity and Growth Plasticity of Asian Short-Toed Lark Nestlings in Response to Changes in Food Conditions: Can It Buffer the Challenge of Climate Change-Induced Trophic Mismatch?

Passerine nestlings frequently suffer from sub-optimal food conditions due to climate change-induced trophic mismatch between the nestlings and their optimal food resources. The ability of nestlings to buffer this challenge is less well understood. We hypothesized that poor food conditions might induce a higher immune response and lower growth rate of nestlings, and such physiological plasticity is conducive to nestling survival. To test this, we examined how food (grasshopper nymphs) abundance affects the expression of interferon-γ (IFN-γ), tumor necrosis factor-α (TNF-α), interleukin-1 β (IL-1β) genes, plasma IGF-1 levels, body mass, and fledging rates in wild Asian short-toed lark (Alaudala cheleensis) nestlings. Linear mixed models revealed that nymph biomass significantly influenced the expression of IFN-γ, TNF-α, and IL-1β genes, and the level of plasma IGF-1. The expressions of IFN-γ, TNF-α, and IL-1β genes were negatively correlated with nymph biomass and plasma IGF-1 level. Plasma IGF-1 level, nestling body mass growth rate, was positively correlated with nymph biomass. Despite a positive correlation between the nestling fledge rate and nymph biomass, more than 60% of nestlings fledged when nymph biomass was at the lowest level. These results suggest that immunity and growth plasticity of nestlings may be an adaptation for birds to buffer the negative effects of trophic mismatch.

Allometry reveals trade-offs between Bergmann's and Allen's rules, and different avian adaptive strategies for thermoregulation

Animals tend to decrease in body size (Bergmann's rule) and elongate appendages (Allen's rule) in warm climates. However, it is unknown whether these patterns depend on each other or constitute independent responses to the thermal environment. Here, based on a global phylogenetic comparative analysis across 99.7% of the world's bird species, we show that the way in which the relative length of unfeathered appendages co-varies with temperature depends on body size and vice versa. First, the larger the body, the greater the increase in beak length with temperature. Second, the temperature-based increase in tarsus length is apparent only in larger birds, whereas in smaller birds, tarsus length decreases with temperature. Third, body size and the length of beak and tarsus interact with each other to predict the species' environmental temperature. These findings suggest that the animals' body size and shape are products of an evolutionary compromise that reflects distinct alternative thermoregulatory adaptations.

Rapidly declining body size in an insectivorous bat is associated with increased precipitation and decreased survival

Reduced food availability is implicated in declines in avian aerial insectivores, but the effect of nutritional stress on mammalian aerial insectivores is unclear. Unlike birds, insectivorous bats provision their young through lactation, which might protect nursing juveniles when prey availability is low but could increase the energetic burden on lactating females. We analyzed a 15-year capture-mark-recapture data set from 5312 individual little brown myotis (Myotis lucifugus) captured at 11 maternity colonies in northwestern Canada, to test the hypothesis that nutritional stress is impacting these mammalian aerial insectivores. We used long-bone (forearm [FA]) length as a proxy for relative access to nutrition during development, and body mass as a proxy for access to nutrition prior to capture. Average FA length and body mass both decreased significantly over the study period in adult females and juveniles, suggesting decreased access to nutrition. Effect sizes were very small, similar to those reported for declining body size in avian aerial insectivores. Declines in juvenile body mass were only observed in individuals captured in late summer when they were foraging independently, supporting our hypothesis that lactation provides some protection to nursing young during periods of nutritional stress. Potential drivers of the decline in bat size include one or both of (1) declining insect (prey) abundance, and (2) declining prey availability. Echolocating insectivorous bats cannot forage effectively during rainfall, which is increasing in our study area. The body mass of captured adult females and juveniles in our study was lower, on average, after periods of high rainfall, and higher after warmer-than-average periods. Finally, survival models revealed a positive association between FA length and survival, suggesting a fitness consequence to declines in body size. Our study area has not yet been impacted by bat white-nose syndrome (WNS), but research elsewhere has suggested that fatter bats are more likely to survive infection. We found evidence for WNS-independent shifts in the body size of little brown myotis, which can inform studies investigating population responses to WNS. More broadly, the cumulative effects of multiple stressors (e.g., disease, nutritional stress, climate change, and other pressures) on mammalian aerial insectivores require urgent attention.

Signals of local bioclimate-driven ecomorphological changes in wild birds

Across disciplines-biological, ecological, evolutionary, or environmental-researchers increasingly recognize the importance and the need for cost-effective, non-invasive techniques for in-situ morphological measurements of organisms in diverse research contexts. By applying a non-invasive technique using digital images taken under field conditions, we successfully measured the body sizes of wild Painted Storks (Mycteria leucocephala) in two different biogeographic regions of India, spatially separated by 20° of latitude. We have used the wild Painted Storks as model species for measuring their morphometrics using a non-invasive technique that could easily be applied to similar species, rare, endemic, colonial, aquatic, and even those with cultural taboos. Our results satisfactorily classify and predict the sexes of the species and their biogeographic origin based on independent morphological variables using Machine Learning algorithms. The BayesNet yielded the correct classification instances (Receiver Operating Characteristic (ROC) = 0.985), outperforming all the other tested classifying algorithms. A strong relationship was observed between the local bioclimatic conditions and the morphological variations in wild Painted Storks reflecting clear eco-geographic patterns. Without this non-invasive technique, it would be almost impossible to collect morphological measurements at a large scale from live birds under field conditions. Our study is a testimony to the effectual use of the non-invasive digital method for in-situ measurements from free-living wild species in the field, assuming significance, especially from climate change perspectives, biology, ecology, and conservation.

Review of contaminant levels and effects in shorebirds: Knowledge gaps and conservation priorities

Environmental pollution has emerged as a major threat to bird populations. Many shorebird populations are declining, although contamination has been documented in some shorebirds, evidence of negative impacts is sparse and this important topic remains understudied. To guide future research and develop effective conservation strategies, we carried out a comprehensive review of environmental pollutants and their consequences on shorebirds. In total, we found 93 relevant articles which examined pollutant contamination in ~37% (79 of 215) of all shorebird species, mostly from the Charadriidae and Scolopacidae families. Studies were geographically biased: the majority were conducted in American flyways, while only 1 was found from Australasia and few were conducted in Asian flyways. The main geographic gap for research includes East Africa, South Asia and Siberian Arctic. The most well-documented pollutants included mercury (Hg, 37 studies), cadmium (33), and lead (Pb, 28); less well studied pollutants were barium (1), calcium (1), strontium (1), dicofols (1), and other newly emerging contaminants, such as plastic debris/microplastics (4) and antibiotics resistance (2). Several pollutants have caused considerable concerns in shorebirds, including embryotoxicity caused by PCBs at non-optimum temperature (laboratory experiments); reduced reproduction performance linked to maternal Hg and paternal Pb (field evidence); and reduced refueling and flight performance related to oil contamination (both field and laboratory evidence). Our results confirm that an in-depth understanding of the local, regional and global factors that influence population trends of shorebirds in light of increasing pollution threats is essential for accurate and effective management and conservation strategies.

Body size responses to the combined effects of climate and land use changes within an urban framework

Alterations in body size can have profound impacts on an organism's life history and ecology with long-lasting effects that span multiple biological scales. Animal body size is influenced by environmental drivers, including climate change and land use change, the two largest current threats to biodiversity. Climate warming has led to smaller body sizes of many species due to impacts on growth (i.e., Bergmann's rule and temperature-size rule). Conversely, urbanization, which serves as a model for investigating the effects of land use changes, has largely been demonstrated to cause size increases, but few studies have examined the combined influences of climate and land use changes on organism size. We present here the background theory on how each of these factors is expected to influence body size, summarize existing evidence of how size has recently been impacted by climate and land use changes, and make several recommendations to guide future research uniting these areas of focus. Given the rapid pace of climate change and urbanization, understanding the combined effects of climate and land use changes on body size is imperative for biodiversity preservation.

Genomic status of yellow-breasted bunting following recent rapid population decline

Global biodiversity is facing serious threats. However, knowledge of the genomic consequences of recent rapid population declines of wild organisms is limited. Do populations experiencing recent rapid population decline have the same genomic status as wild populations that experience long-term declines? Yellow-breasted Bunting (Emberiza aureola) is a critically endangered species that has been experiencing a recent rapid population decline. To answer the question, we assembled and annotated the whole genome of Yellow-breasted Bunting. Furthermore, we found high genetic diversity, low linkage disequilibrium, and low proportion of long runs of homozygosity in Yellow-breasted Bunting, suggesting that the populations following recent rapid declines have different genomic statuses from the population that experienced long-term population decline.

Combining Multispectral and Radar Imagery with Machine Learning Techniques to Map Intertidal Habitats for Migratory Shorebirds

Migratory shorebirds are notable consumers of benthic invertebrates on intertidal sediments. The distribution and abundance of shorebirds will strongly depend on their prey and on landscape and sediment features such as mud and surface water content, topography, and the presence of ecosystem engineers. An understanding of shorebird distribution and ecology thus requires knowledge of the various habitat types which may be distinguished in intertidal areas. Here, we combine Sentinel-1 and Sentinel-2 imagery and a digital elevation model (DEM), using machine learning techniques to map intertidal habitat types of importance to migratory shorebirds and their benthic prey. We do this on the third most important non-breeding area for migratory shorebirds in the East Atlantic Flyway, in the Bijagós Archipelago in West Africa. Using pixel-level random forests, we successfully mapped rocks, shell beds, and macroalgae and distinguished between areas of bare sediment and areas occupied by fiddler crabs, an ecosystem engineer that promotes significant bioturbation on intertidal flats. We also classified two sediment types (sandy and mixed) within the bare sediment and fiddler crab areas, according to their mud content. The overall classification accuracy was 82%, and the Kappa Coefficient was 73%. The most important predictors were elevation, the Sentinel-2-derived water and moisture indexes, and Sentinel-1 VH band. The association of Sentinel-2 with Sentinel-1 and a DEM produced the best results compared to the models without these variables. This map provides an overall picture of the composition of the intertidal habitats in a site of international importance for migratory shorebirds. Most of the intertidal flats of the Bijagós Archipelago are covered by bare sandy sediments (59%), and ca. 22% is occupied by fiddler crabs. This likely has significant implications for the spatial arrangement of the shorebird and benthic invertebrate communities due to the ecosystem engineering by the fiddler crabs, which promotes two vastly different intertidal species assemblages. This large-scale mapping provides an important product for the future monitoring of this high biodiversity area, particularly for ecological research related to the distribution and feeding ecology of the shorebirds and their prey. Such information is key from a conservation and management perspective. By delivering a successful and comprehensive mapping workflow, we contribute to the filling of the current knowledge gap on the application of remote sensing and machine learning techniques within intertidal areas, which are among the most challenging environments to map using remote sensing techniques.

Sulfur in lucinid bivalves inhibits intake rates of a molluscivore shorebird

A forager's energy intake rate is usually constrained by a combination of handling time, encounter rate and digestion rate. On top of that, food intake may be constrained when a forager can only process a maximum amount of certain toxic compounds. The latter constraint is well described for herbivores with a limited tolerance to plant secondary metabolites. In sulfidic marine ecosystems, many animals host chemoautotrophic endosymbionts, which store sulfur compounds as an energy resource, potentially making their hosts toxic to predators. The red knot Calidris canutus canutus is a molluscivore shorebird that winters on the mudflats of Banc d'Arguin, where the most abundant bivalve prey Loripes orbiculatus hosts sulfide-oxidizing bacteria. In this system, we studied the potential effect of sulfur on the red knots' intake rates, by offering Loripes with various sulfur content to captive birds. To manipulate toxicity, we starved Loripes for 10 days by removing them from their symbiont's energy source sulfide. As predicted, we found lower sulfur concentrations in starved Loripes. We also included natural variation in sulfur concentrations by offering Loripes collected at two different locations. In both cases lower sulfur levels in Loripes resulted in higher consumption rates in red knots. Over time the red knots increased their intake rates on Loripes, showing their ability to adjust to a higher intake of sulfur.

Global flyway evolution in red knots Calidris canutus and genetic evidence for a Nearctic refugium

Present‐day ecology and population structure are the legacies of past climate and habitat perturbations, and this is particularly true for species that are widely distributed at high latitudes. The red knot, Calidris canutus, is an arctic‐breeding, long‐distance migratory shorebird with six recognized subspecies defined by differences in morphology, migration behavior, and annual cycle phenology, in a global distribution thought to have arisen just since the last glacial maximum (LGM). We used nextRAD sequencing of 10,881 single‐nucleotide polymorphisms (SNPs) to assess the neutral genetic structure and phylogeographic history of 172 red knots representing all known global breeding populations. Using population genetics approaches, including model‐based scenario‐testing in an approximate Bayesian computation (ABC) framework, we infer that red knots derive from two main lineages that diverged ca. 34,000 years ago, and thus most probably persisted at the LGM in both Palearctic and Nearctic refugia, followed by at least two instances of secondary contact and admixture. Within two Beringian subspecies (C. c. roselaari and rogersi), we detected previously unknown genetic structure among sub‐populations sharing a migratory flyway, reflecting additional complexity in the phylogeographic history of the region. Conversely, we found very weak genetic differentiation between two Nearctic populations (rufa and islandica) with clearly divergent migratory phenotypes and little or no apparent contact throughout the annual cycle. Together, these results suggest that relative gene flow among migratory populations reflects a complex interplay of historical, geographical, and ecological factors.

Mismatch-induced growth reductions in a clade of Arctic-breeding shorebirds are rarely mitigated by increasing temperatures

In seasonal environments subject to climate change, organisms typically show phenological changes. As these changes are usually stronger in organisms at lower trophic levels than those at higher trophic levels, mismatches between consumers and their prey may occur during the consumers' reproduction period. While in some species a trophic mismatch induces reductions in offspring growth, this is not always the case. This variation may be caused by the relative strength of the mismatch, or by mitigating factors like increased temperature-reducing energetic costs. We investigated the response of chick growth rate to arthropod abundance and temperature for six populations of ecologically similar shorebirds breeding in the Arctic and sub-Arctic (four subspecies of Red Knot Calidris canutus, Great Knot C. tenuirostris and Surfbird C. virgata). In general, chicks experienced growth benefits (measured as a condition index) when hatching before the seasonal peak in arthropod abundance, and growth reductions when hatching after the peak. The moment in the season at which growth reductions occurred varied between populations, likely depending on whether food was limiting growth before or after the peak. Higher temperatures led to faster growth on average, but could only compensate for increasing trophic mismatch for the population experiencing the coldest conditions. We did not find changes in the timing of peaks in arthropod availability across the study years, possibly because our series of observations was relatively short; timing of hatching displayed no change over the years either. Our results suggest that a trend in trophic mismatches may not yet be evident; however, we show Arctic-breeding shorebirds to be vulnerable to this phenomenon and vulnerability to depend on seasonal prey dynamics.

Understanding the dynamics of Arctic animal migrations in a changing world

This is submitted as an introduction to the special collection on, “Arctic Migrations in a Changing World”.

Timing of Breeding Site Availability Across the North-American Arctic Partly Determines Spring Migration Schedule in a Long-Distance Neotropical Migrant

Long-distance migrants are under strong selection to arrive on their breeding grounds at a time that maximizes fitness. Many arctic birds start nesting shortly after snow recedes from their breeding sites and timing of snowmelt can vary substantially over the breeding range of widespread species. We tested the hypothesis that migration schedules of individuals co-occurring at the same non-breeding areas are adapted to average local environmental conditions encountered at their specific and distant Arctic breeding locations. We predicted that timing of breeding site availability (measured here as the average snow-free date) should explain individual variation in departure time from shared non-breeding areas. We tested our prediction by tracking American Golden-Plovers (Pluvialis dominica) nesting across the North-American Arctic. These plovers use a non-breeding (wintering) area in South America and share a spring stopover area in the nearctic temperate grasslands, located &gt;1,800 km away from their nesting locations. As plovers co-occur at the same non-breeding areas but use breeding sites segregated by latitude and longitude, we could disentangle the potential confounding effects of migration distance and timing of breeding site availability on individual migration schedule. As predicted, departure date of individuals stopping-over in sympatry was positively related to the average snow-free date at their respective breeding location, which was also related to individual onset of incubation. Departure date from the shared stopover area was not explained by the distance between the stopover and the breeding location, nor by the stopover duration of individuals. This strongly suggests that plover migration schedule is adapted to and driven by the timing of breeding site availability per se. The proximate mechanism underlying the variable migration schedule of individuals is unknown and may result from genetic differences or individual learning. Temperatures are currently changing at different speeds across the Arctic and this likely generates substantial heterogeneity in the strength of selection pressure on migratory schedule of arctic birds migrating sympatrically.

Environmental conditions variably affect growth across the breeding season in a subarctic seabird

Predicting the impacts of changing environments on phenotypes in wild populations remains a challenge. Growth, a trait that frequently influences fitness, is difficult to study as it is influenced by many environmental variables. To address this, we used a sliding window approach to determine the time windows when sea-surface and air temperatures have the potential to affect growth of black-legged kittiwakes (Rissa tridactyla) on a colony in the Northeast Pacific. We examined environmental drivers influencing nestling growth using data from a long-term (21-year) study, that food supplements a portion of the colony. The associations between kittiwake growth and climatic conditions in our study indicated that warmer environmental conditions can both positively and negatively impact nestling growth parameters depending on hatching order. We found that first-hatched nestlings had a heavier maximum mass under warm air temperatures and cold sea conditions. Warmer air temperatures negatively affected the second-hatched nestling in a brood. However, when air temperatures were warm, warmer sea-surface temperatures predicted heavy, fast-growing second-hatched nestlings in contrast to what we observed for first-hatched nestlings. Food supplementation alleviated the temperature effects, and competition among nestlings influenced how strongly a variable affected growth. We identified windows that might indicate specific biological pathways through which environmental variation affected growth directly or indirectly. Overall, our windows suggest that nestlings in shared nests will be most affected by warming conditions.

Flyway-scale analysis reveals that the timing of migration in wading birds is becoming later

Understanding the implications of climate change for migratory animals is paramount for establishing how best to conserve them. A large body of evidence suggests that birds are migrating earlier in response to rising temperatures, but many studies focus on single populations of model species.Migratory patterns at large spatial scales may differ from those occurring in single populations, for example because of individuals dispersing outside of study areas. Furthermore, understanding phenological trends across species is vital because we need a holistic understanding of how climate change affects wildlife, especially as rates of temperature change vary globally.The life cycles of migratory wading birds cover vast latitudinal gradients, making them particularly susceptible to climate change and, therefore, ideal model organisms for understanding its effects. Here, we implement a novel application of changepoint detection analysis to investigate changes in the timing of migration in waders at a flyway scale using a thirteen-year citizen science dataset (eBird) and determine the influence of changes in weather conditions on large-scale migratory patterns.In contrast to most previous research, our results suggest that migration is getting later in both spring and autumn. We show that rates of change were faster in spring than autumn in both the Afro-Palearctic and Nearctic flyways, but that weather conditions in autumn, not in spring, predicted temporal changes in the corresponding season. Birds migrated earlier in autumn when temperatures increased rapidly, and later with increasing headwinds.One possible explanation for our results is that migration is becoming later due to northward range shifts, which means that a higher proportion of birds travel greater distances and therefore take longer to reach their destinations. Our findings underline the importance of considering spatial scale when investigating changes in the phenology of migratory bird species.

Animal migration to northern latitudes: environmental changes and increasing threats

Every year, many wild animals undertake long-distance migration to breed in the north, taking advantage of seasonally high pulses in food supply, fewer parasites, and lower predation pressure in comparison with equatorial latitudes. Growing evidence suggests that climate-change-induced phenological mismatches have reduced food availability. Furthermore, novel pathogens and parasites are spreading northwards, and nest or offspring predation has increased at many Arctic and northern temperate locations. Altered trophic interactions have decreased the reproductive success and survival of migratory animals. Reduced advantages for long-distance migration have potentially serious consequences for community structure and ecosystem function. Changes in the benefits of migration need to be integrated into projections of population and ecosystem dynamics and targeted by innovative conservation actions.

Shape-shifting: changing animal morphologies as a response to climatic warming

Many animal appendages, such as avian beaks and mammalian ears, can be used to dissipate excess body heat. Allen's rule, wherein animals in warmer climates have larger appendages to facilitate more efficient heat exchange, reflects this. We find that there is widespread evidence of 'shape-shifting' (changes in appendage size) in endotherms in response to climate change and its associated climatic warming. We re-examine studies of morphological change over time within a thermoregulatory context, finding evidence that temperature can be a strong predictor of morphological change independently of, or combined with, other environmental changes. Last, we discuss how Allen's rule, the degree of temperature change, and other ecological factors facilitate morphological change and make predictions about what animals will show shape-shifting.

Population consequences of climate change through effects on functional traits of lentic brown trout in the sub-Arctic

Climate-induced plasticity in functional traits has received recent attention due to the immense importance phenotypic variation plays in population level responses. Here, we explore the effect of different climate-change scenarios on lentic populations of a freshwater ectotherm, the brown trout (Salmo trutta L.), through climate effects on functional traits. We first parameterize models of climate variables on growth, spawning probability and fecundity. The models are utilized to inform a dynamic age-structured projection matrix, enabling long-term population viability projections under climate and population density variation. Ambient temperature and winter conditions had a substantial effect on population growth rate. In general, warmer summer temperatures resulted in faster growth rates for young fish but ended in smaller size at age as fish got older. Increasing summer temperatures also induced maturation at younger age and smaller size. In addition, we found effects of first-year growth on later growth trajectories for a fish, indicating that environmental conditions experienced the first year will also influence size at age later in life. At the population level, increasing temperatures average (up to 4 °C increase in areas with mean summer temperature at approximately 12 °C) resulted in a positive effect on population growth rate (i.e. smaller but more fish) during climate simulations including increasing and more variable temperatures.

Widespread shifts in bird migration phenology are decoupled from parallel shifts in morphology

Advancements in phenology and changes in morphology, including body size reductions, are among the most commonly described responses to globally warming temperatures. Although these dynamics are routinely explored independently, the relationships among them and how their interactions facilitate or constrain adaptation to climate change are poorly understood. In migratory species, advancing phenology may impose selection on morphological traits to increase migration speed. Advancing spring phenology might also expose species to cooler temperatures during the breeding season, potentially mitigating the effect of a warming global environment on body size. We use a dataset of birds that died after colliding with buildings in Chicago, IL to test whether changes in migration phenology are related to documented declines in body size and increases in wing length in 52 North American migratory bird species between 1978 and 2016. For each species, we estimate temporal trends in morphology and changes in the timing of migration. We then test for associations between species-specific rates of phenological and morphological changes while assessing the potential effects of migratory distance and breeding latitude. We show that spring migration through Chicago has advanced while the timing of fall migration has broadened as a result of early fall migrants advancing their migrations and late migrants delaying their migrations. Within species, we found that longer wing length was linked to earlier spring migration within years. However, we found no evidence that rates of phenological change across years, or migratory distance and breeding latitude, are predictive of rates of concurrent changes in morphological traits. These findings suggest that biotic responses to climate change are highly multidimensional and the extent to which those responses interact and influence adaptation to climate change requires careful examination.

Nocturnal foraging lifts time constraints in winter for migratory geese but hardly speeds up fueling

Climate warming advances the optimal timing of breeding for many animals. For migrants to start breeding earlier, a concurrent advancement of migration is required, including premigratory fueling of energy reserves. We investigate whether barnacle geese are time constrained during premigratory fueling and whether there is potential to advance or shorten the fueling period to allow an earlier migratory departure. We equipped barnacle geese with GPS trackers and accelerometers to remotely record birds’ behavior, from which we calculated time budgets. We examined how time spent foraging was affected by the available time (during daylight and moonlit nights) and thermoregulation costs. We used an energetic model to assess onset and rates of fueling and whether geese can further advance fueling by extending foraging time. We show that, during winter, when facing higher thermoregulation costs, geese consistently foraged at night, especially during moonlit nights, in order to balance their energy budgets. In spring, birds made use of the increasing day length and gained body stores by foraging longer during the day, but birds stopped foraging extensively during the night. Our model indicates that, by continuing nighttime foraging throughout spring, geese may have some leeway to advance and increase fueling rate, potentially reaching departure body mass 4 days earlier. In light of rapid climatic changes on the breeding grounds, whether this advancement can be realized and whether it will be sufficient to prevent phenological mismatches remains to be determined.

Early warning indicators of population collapse in a seasonal environment

Recent studies have demonstrated that generic statistical signals derived from time series of population abundance and fitness-related traits of individuals can provide reliable indicators of impending shifts in population dynamics. However, how the seasonal timing of environmental stressors influences these early warning indicators is not well understood. The goal of this study was to experimentally assess whether the timing of stressors influences the production, detection and sensitivity of abundance- and trait-based early warning indicators derived from declining populations. In a multi-generation, season-specific habitat loss experiment, we exposed replicate populations of Drosophila melanogaster to one of two rates of chronic habitat loss (10% or 20% per generation) in either the breeding or the non-breeding period. We counted population abundance at the beginning of each season, and measured body mass and activity levels in a sample of individuals at the end of each generation. When habitat was lost during the breeding period, declining populations produced signals consistent with those documented in previous studies. Inclusion of trait-based indicators generally improved the detection of impending population collapse. However, when habitat was lost during the non-breeding period, the predictive capacity of these indicators was comparatively diminished. Our results have important implications for interpreting signals in the wild because they suggest that the production and detection of early warning indicators depends on the season in which stressors occur, and that this is likely related to the capacity of populations to respond numerically the following season.

Global population trends in shorebirds: migratory behaviour makes species at risk

Linking population trends to species' traits is informative for the detection of the most important threatening factors and for assessing the effectiveness of conservation measures. Although some previous studies performed such an analysis at local to continental scales, the global-scale focus is the most relevant for conservation of the entire species. Here we evaluate information on global population trends of shorebirds, a widely distributed and ecologically diversified group, where some species connect different parts of the world by migration, while others are residents. Nowadays, shorebirds face rapid environmental changes caused by various human activities and climate change. Numerous signs of regional population declines have been recently reported in response to these threats. The aim of our study was to test whether breeding and non-breeding habitats, migratory behaviour (migrants vs. residents) and migration distance, breeding latitude, generation time and breeding range size mirror species' global population trends. We found that a majority of shorebird species have declined globally. After accounting for the influence of traits and species taxonomy, linear mixed-effects models showed that populations of migratory shorebirds decreased more than populations of residents. Besides that, declines were more frequent for species breeding at high latitudes of the Northern Hemisphere, but these patterns did not hold after excluding the non-migratory species. Our findings suggest that factors linked to migration, such as habitat loss as well as deterioration at stop-over or wintering sites and a pronounced climate change impact at high latitudes, are possible drivers of the observed worldwide population decreases.

Predictors of invertebrate biomass and rate of advancement of invertebrate phenology across eight sites in the North American Arctic

Average annual temperatures in the Arctic increased by 2–3 °C during the second half of the twentieth century. Because shorebirds initiate northward migration to Arctic nesting sites based on cues at distant wintering grounds, climate-driven changes in the phenology of Arctic invertebrates may lead to a mismatch between the nutritional demands of shorebirds and the invertebrate prey essential for egg formation and subsequent chick survival. To explore the environmental drivers affecting invertebrate availability, we modeled the biomass of invertebrates captured in modified Malaise-pitfall traps over three summers at eight Arctic Shorebird Demographics Network sites as a function of accumulated degree-days and other weather variables. To assess climate-driven changes in invertebrate phenology, we used data from the nearest long-term weather stations to hindcast invertebrate availability over 63 summers, 1950–2012. Our results confirmed the importance of both accumulated and daily temperatures as predictors of invertebrate availability while also showing that wind speed negatively affected invertebrate availability at the majority of sites. Additionally, our results suggest that seasonal prey availability for Arctic shorebirds is occurring earlier and that the potential for trophic mismatch is greatest at the northernmost sites, where hindcast invertebrate phenology advanced by approximately 1–2.5 days per decade. Phenological mismatch could have long-term population-level effects on shorebird species that are unable to adjust their breeding schedules to the increasingly earlier invertebrate phenologies.

The Effects of Weather on Avian Growth and Implications for Adaptation to Climate Change

Climate change is forecasted to generate a range of evolutionary changes and plastic responses. One important aspect of avian responses to climate change is how weather conditions may change nestling growth and development. Early life growth is sensitive to environmental effects and can potentially have long-lasting effects on adult phenotypes and fitness. A detailed understanding of both how and when weather conditions affect the entire growth trajectory of a nestling may help predict population changes in phenotypes and demography under climate change. This review covers three main topics on the impacts of weather variation (air temperature, rainfall, wind speed, solar radiation) on nestling growth. Firstly, we highlight why understanding the effects of weather on nestling growth might be important in understanding adaptation to, and population persistence in, environments altered by climate change. Secondly, we review the documented effects of weather variation on nestling growth curves. We investigate both altricial and precocial species, but we find a limited number of studies on precocial species in the wild. Increasing temperatures and rainfall have mixed effects on nestling growth, while increasing windspeeds tend to have negative impacts on the growth rate of open cup nesting species. Thirdly, we discuss how weather variation might affect the evolution of nestling growth traits and suggest that more estimates of the inheritance of and selection acting on growth traits in natural settings are needed to make evolutionary predictions. We suggest that predictions will be improved by considering concurrently changing selection pressures like urbanization. The importance of adaptive plastic or evolutionary changes in growth may depend on where a species or population is located geographically and the species’ life-history. Detailed characterization of the effects of weather on growth patterns will help answer whether variation in avian growth frequently plays a role in adaption to climate change.

Animal board invited review: OneARK: Strengthening the links between animal production science and animal ecology

Wild and farmed animals are key elements of natural and managed ecosystems that deliver functions such as pollination, pest control and nutrient cycling within the broader roles they play in contributing to biodiversity and to every category of ecosystem services. They are subjected to global changes with a profound impact on the natural range and viability of animal species, the emergence and spatial distribution of pathogens, land use, ecosystem services and farming sustainability. We urgently need to improve our understanding of how animal populations can respond adaptively and therefore sustainably to these new selective pressures. In this context, we explored the common points between animal production science and animal ecology to identify promising avenues of synergy between communities through the transfer of concepts and/or methodologies, focusing on seven concepts that link both disciplines. Animal adaptability, animal diversity (both within and between species), selection, animal management, animal monitoring, agroecology and viability risks were identified as key concepts that should serve the cross-fertilization of both fields to improve ecosystem resilience and farming sustainability. The need for breaking down interdisciplinary barriers is illustrated by two representative examples: i) the circulation and reassortment of pathogens between wild and domestic animals and ii) the role of animals in nutrient cycles, i.e. recycling nitrogen, phosphorus and carbon through, for example, contribution to soil fertility and carbon sequestration. Our synthesis identifies the need for knowledge integration techniques supported by programmes and policy tools that reverse the fragmentation of animal research toward a unification into a single Animal Research Kinship, OneARK, which sets new objectives for future science policy. At the interface of animal ecology and animal production science, our article promotes an effective application of the agroecology concept to animals and the use of functional diversity to increase resilience in both wild and farmed systems. It also promotes the use of novel monitoring technologies to quantify animal welfare and factors affecting fitness. These measures are needed to evaluate viability risk, predict and potentially increase animal adaptability and improve the management of wild and farmed systems, thereby responding to an increasing demand of society for the development of a sustainable management of systems.