Seasonally abundant arthropods are a crucial food source for many migratory birds that breed in the Arctic. In cold environments, the growth and emergence of arthropods are particularly tied to temperature. Thus, the phenology of arthropods is anticipated to undergo a rapid change in response to a warming climate, potentially leading to a trophic mismatch between migratory insectivorous birds and their prey. Using data from 19 sites spanning a wide temperature gradient from the Subarctic to the High Arctic, we investigated the effects of temperature on the phenology and biomass of arthropods available to shorebirds during their short breeding season at high latitudes. We hypothesized that prolonged exposure to warmer summer temperatures would generate earlier peaks in arthropod biomass, as well as higher peak and seasonal biomass. Across the temperature gradient encompassed by our study sites (>10°C in average summer temperatures), we found a 3-day shift in average peak date for every increment of 80 cumulative thawing degree-days. Interestingly, we found a linear relationship between temperature and arthropod biomass only below temperature thresholds. Higher temperatures were associated with higher peak and seasonal biomass below 106 and 177 cumulative thawing degree-days, respectively, between June 5 and July 15. Beyond these thresholds, no relationship was observed between temperature and arthropod biomass. Our results suggest that prolonged exposure to elevated temperatures can positively influence prey availability for some arctic birds. This positive effect could, in part, stem from changes in arthropod assemblages and may reduce the risk of trophic mismatch.

Global climate change has altered the timing of seasonal events (i.e., phenology) for a diverse range of biota. Within and among species, however, the degree to which alterations in phenology match climate variability differ substantially. To better understand factors driving these differences, we evaluated variation in timing of nesting of eight Arctic-breeding shorebird species at 18 sites over a 23-year period. We used the Normalized Difference Vegetation Index as a proxy to determine the start of spring (SOS) growing season and quantified relationships between SOS and nest initiation dates as a measure of phenological responsiveness. Among species, we tested four life history traits (migration distance, seasonal timing of breeding, female body mass, expected female reproductive effort) as species-level predictors of responsiveness. For one species (Semipalmated Sandpiper), we also evaluated whether responsiveness varied across sites. Although no species in our study completely tracked annual variation in SOS, phenological responses were strongest for Western Sandpipers, Pectoral Sandpipers, and Red Phalaropes. Migration distance was the strongest additional predictor of responsiveness, with longer-distance migrant species generally tracking variation in SOS more closely than species that migrate shorter distances. Semipalmated Sandpipers are a widely distributed species, but adjustments in timing of nesting relative to variability in SOS did not vary across sites, suggesting that different breeding populations of this species were equally responsive to climate cues despite differing migration strategies. Our results unexpectedly show that long-distance migrants are more sensitive to local environmental conditions, which may help them to adapt to ongoing changes in climate.

Determining the dynamics of where and when individuals occur is necessary to understand population declines and identify critical areas for populations of conservation concern. However, there are few examples where a spatially and temporally explicit model has been used to evaluate the migratory dynamics of a bird population across its entire annual cycle. We used geolocator-derived migration tracks of 84 Dunlin (Calidris alpina) on the East Asian-Australasian Flyway (EAAF) to construct a migratory network describing annual subspecies-specific migration patterns in space and time. We found that Dunlin subspecies exhibited unique patterns of spatial and temporal flyway use. Spatially, C. a. arcticola predominated in regions along the eastern edge of the flyway (e.g., western Alaska and central Japan), whereas C. a. sakhalina predominated in regions along the western edge of the flyway (e.g., N China and inland China). No individual Dunlin that wintered in Japan also wintered in the Yellow Sea, China seas, or inland China, and vice-versa. However, similar proportions of the 4 subspecies used many of the same regions at the center of the flyway (e.g., N Sakhalin Island and the Yellow Sea). Temporally, Dunlin subspecies staggered their south migrations and exhibited little temporal overlap among subspecies within shared migration regions. In contrast, Dunlin subspecies migrated simultaneously during north migration. South migration was also characterized by individuals stopping more often and for more days than during north migration. Taken together, these spatial-temporal migration dynamics indicate Dunlin subspecies may be differentially affected by regional habitat change and population declines according to where and when they occur. We suggest that the migration dynamics presented here are useful for guiding on-the-ground survey efforts to quantify subspecies’ use of specific sites, and to estimate subspecies’ population sizes and long-term trends. Such studies would significantly advance our understanding of Dunlin space-time dynamics and the coordination of Dunlin conservation actions across the EAAF.

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 degree to which individuals migrate among particular breeding, migration, and wintering sites can have important implications for prioritizing conservation efforts. Four subspecies of Dunlin (Calidris alpina) migrate along the East Asian-Australasian Flyway. Each subspecies has a distinct and well-defined breeding range, but their migration and winter ranges are poorly defined or unknown. We assessed the migratory connectivity of 3 of these subspecies by evaluating a dataset that encompasses 57 yr (1960-2017), and comprises more than 28,000 Dunlin banding records and 818 observations (71 recaptures and 747 band resightings). We present some of the first evidence that subspecific segregation likely occurs, with arcticola Dunlin wintering in areas of Japan, and other arcticola, actites, and sakhalina Dunlin wintering in areas of the Yellow and China seas. Observations indicate that whether an arcticola Dunlin winters in Japan or the Yellow and China seas is independent of their breeding location, sex, or age. Furthermore, observations indicate that 83% of arcticola Dunlin exhibit interannual site fidelity to specific wintering sites. This suggests that the degradation of specific wetland areas may negatively affect particular individuals of a particular subspecies (or combination of subspecies), and, if widespread, could result in population declines. Given the possible biases inherent in analyzing band recovery data, we recommend additional flyway-wide collaboration and the use of lightweight tracking devices and morphological and genetic assignment techniques to better quantify subspecies' migratory movements and nonbreeding distributions. This information, when combined, will enable effective conservation efforts for this species across the East Asian-Australasian Flyway.

ABSTRACT Conservation status and management priorities are often informed by population trends. Trend estimates can be derived from population surveys or models, but both methods are associated with sources of uncertainty. Many Arctic-breeding shorebirds are thought to be declining based on migration and/or overwintering population surveys, but data are lacking to estimate the trends of some shorebird species. In addition, for most species, little is known about the stage(s) at which population bottlenecks occur, such as breeding vs. nonbreeding periods. We used previously published and unpublished estimates of vital rates to develop the first large-scale population models for 6 species of Arctic-breeding shorebirds in North America, including separate estimates for 3 subspecies of Dunlin. We used the models to estimate population trends and identify life stages at which population growth may be limited. Our model for the arcticola subspecies of Dunlin agreed with previously published information that the subspecies is severely declining. Our results also linked the decline to the subspecies' low annual adult survival rate, thus potentially implicating factors during the nonbreeding period in the East Asian–Australasian Flyway. However, our trend estimates for all species showed high uncertainty, highlighting the need for more accurate and precise estimates of vital rates. Of the vital rates, annual adult survival had the strongest influence on population trend in all taxa. Improving the accuracy, precision, and spatial and temporal coverage of estimates of vital rates, especially annual adult survival, would improve demographic model-based estimates of population trends and help direct management to regions or seasons where birds are subject to higher mortality. LAY SUMMARY Documenting population trends is essential for evaluating the conservation status of wild species such as Arctic-breeding shorebirds. Trends can be estimated with population surveys or by predicting population growth based on survival rates and fecundity, but both methods are challenging, especially for species with large or remote geographic distributions. We used recent broad-scale estimates of survival and fecundity to develop population models for 6 species of Arctic-breeding shorebirds. The arcticola subspecies of Dunlin is likely in severe decline, but our trend estimates for all species showed high uncertainty. Uncertainty around the values of annual adult survival rates was a key driver of the uncertainty around the trend estimates. Our work highlights the need for better estimates of annual adult survival, seasonal survival, juvenile survival, and breeding propensity for these Arctic-breeding shorebirds.

Kubelka et al. (Science, 9 November 2018, p. 680-683) claim that climate change has disrupted patterns of nest predation in shorebirds. They report that predation rates have increased since the 1950s, especially in the Arctic. We describe methodological problems with their analyses and argue that there is no solid statistical support for their claims.

Turtles are hard-backed reptiles, living in seawater and breeding eggs. Turtles are classified as animals that are protected by the CITES Appendix I (Convention on International Trade in Endangered Species) category. So that all forms of utilization and distribution must receive serious attention. The location of turtle nesting is a wide and gentle sandy beach area and is located on the upper coast. Location of turtle nesting in North Halmahera Regency is Meti Island and Pasir Timbul Island. This study aims to determine the effect of sand structure and environmental hue to determine the location of turtle nesting. Research using a purposive sampling method was carried out intentionally based on information obtained from the community. Appendix data regarding the structure of sand, temperature, moisture content of the nesting sphere and documentation of vegetation is carried out directly in the field. The results of substrate analysis of the nesting on Meti Island in LP1 location were dominated by granules of 0.425-1 mm by 33.45%, 0.25-0.425 mm by 27.09% and 0.125-0.25 mm by 24.62%. LP2 locations are dominated by granules category of 0.425-1 mm by 31.47%, 0.25-0.425 mm by 28.46% and 0.125-0.25 mm by 20.07%. LP3 locations are dominated by the 0.425-1mm granules category at 34.41% and 0.25-0.425 mm at 31.95%. LP1 nesting temperature ranges around 29.2-31.2 ° C, LP2 ranges between 29.9-31.9° C and LP3 ranges between 30.4-32.1° C. LP1 nesting nest water level ranges between 8.4-10.3° C, LP2 ranges between 8.2-9.7 ° C and LP3 ranges between 6.5-8.9. Sea location of spawning nesting consists of Enhalus acoroides and Sargasum arnaudianum which is a suitable habitat for hatchling enlargement areas. The coastline of the LP1 and LP2 spawning sites has a slope of 35°, while LP3 has a beach slope that varies from 35° to 45° and even some parts of the island of LP3 have a slope of up to 90° due to abrasion so that it becomes a barrier for turtles to reach the spawning location. Land vegetation at LP1 and LP2 locations is dominated by large tree-shaped plants while the LP3 location is dominated by shrubs and creeping plants.

Kubelka et al. (Reports, 9 November 2018, p. 680) claim that climate change has disrupted patterns of nest predation in shorebirds. They report that predation rates have increased since the 1950s, especially in the Arctic. We describe methodological problems with their analyses and argue that there is no solid statistical support for their claims.

Responses to climate change can vary across functional groups and trophic levels, leading to a temporal decoupling of trophic interactions or “phenological mismatches.” Despite a growing number of single-species studies that identified phenological mismatches as a nearly universal consequence of climate change, we have a limited understanding of the spatial variation in the intensity of this phenomenon and what influences this variation. In this study, we tested for geographic patterns in phenological mismatches between six species of shorebirds and their invertebrate prey at 10 sites spread across ~13° latitude and ~84° longitude in the Arctic over three years. At each site, we quantified the phenological mismatch between shorebirds and their invertebrate prey at (1) an individual-nest level, as the difference in days between the seasonal peak in food and the peak demand by chicks, and (2) a population level, as the overlapped area under fitted curves for total daily biomass of invertebrates and dates of the peak demand by chicks. We tested whether the intensity of past climatic change observed at each site corresponded with the extent of phenological mismatch and used structural equation modeling to test for causal relationships among (1) environmental factors, including geographic location and current climatic conditions, (2) the timing of invertebrate emergence and the breeding phenology of Manuscript received 4 May 2018; revised 5 May 2019; accepted 17 May 2019. Corresponding Editor: Viviana Ruiz-Gutierrez. 15 Present address: Department of Behavioural Ecology and Evolutionary Genetics, Max Planck Institute for Ornithology, Seewiesen, 82319 Germany 16 Present address: Upper Midwest Environmental Sciences Center, U.S. Geological Survey, La Crosse, Wisconsin 54603 USA. 17 Present address: Pacifica Ecological Services, Anchorage, Alaska 99516 USA. 18 Present address: Hakalau Forest National Wildlife Refuge, Hilo, Hawaii 96720 USA. 19 Present address: Department of Multidisciplinary Studies Bilingual Biology Program, Glendon College, York University, Toronto, Ontario M4N 3M6 Canada. 20 Present address: National Park Service, Alaska Regional Office, Anchorage, Alaska 99507 USA. 21 Present address: Anchorage Fish and Wildlife Conservation Office, U.S. Fish and Wildlife Service, Anchorage, Alaska 99507 USA. 22 Present address: Department of Biological Sciences, University of South Carolina, Columbia, South Carolina 29208 USA. 23 Present address: Department of Terrestrial Ecology, Norwegian Institute for Nature Research, 7485 Trondheim, Norway. 24 E-mail: eunbi.kwon@gmail.com Article e01383; page 1 Ecological Monographs, 0(0), 2019, e01383 © 2019 by the Ecological Society of America

------------------------------------------------------------------------------------------------------Description of the dataset "Supplementary Data 3 - Study sites.csv"--------------------------------------------------------------------------------------------------------The dataset- is used in the paper "Unexpected diversity in socially synchronized rhythms of shorebirds" Nature 2016 by M. Bulla et al- contains estimates of mean female and male wing length for each population of biparental shorebirds from a specific study site, plus the locations of the study site, whether the locations had tide, and whether the tide was used by the population for foraging, and how the incubation was monitored.--------------------------------------------------------------------------------------------------------Questions can be directed to: Martin Bulla (bulla.mar@gmail.com)--------------------------------------------------------------------------------------------------------Values are separated by comma.--------------------------------------------------------------------------------------------------------1. scinam : scientific name of the species2. sp : four letter abbreviation of the species's English name3. study_site : name of the study site4. site_abbreviation : four letter abbreviation of the study site5. type : was the study site at the breeding ground (breeding) or not (wintering)6. lat : latitude of the study site (decimal)7. lon : longitude of the study site (decimal)8. tidal_habitat : is the study site at primarily tidal habitat (y=yes, n=no)9. tidal_used : if the study site is at primarily tidal habitat, do the birds use it for foraging (y=yes, n=no)10. incubation_monitoring : method used to monitor incubation (for details see the paper's Extended Data Table 4)11. sexing_method : identifies the method used to sex individuals to estimate the mean female and male wing length12. pop_wing_f : mean female wing length for the population13. f_wing_N : sample size used for the female mean estimate14. pop_wing_m : mean male wing length for the population15. m_wing_N : sample size used for the male mean estimate16. data_source : is the mean wing estimate based on the primary data ("our primary data") or literature (citation))--------------------------------------------------------------------------------------------------------WHEN USING THIS DATA, PLEASE CITE:Bulla et al (2016). Supplementary Data 3 - Study sites: location, population wing length, monitoring method, tide.figshare. https://doi.org/10.6084/m9.figshare.1536260. Retrieved ADD DATETIME.--------------------------------------------------------------------------------------------------------

Socially synchronized rhythms in shorebirds were assessed during biparental incubation under natural circumstances and were exceptionally diverse, often not following the 24-h day, whereby risk of predation, not starvation, determined some of the variation in incubation rhythms. All organisms have biorhythms, but in social species these have to be synchronized between individuals within a community. Here Martin Bulla et al. address the issue of how parents synchronize their biorhythms when both are caring for their offspring. Using data from 729 nests of 91 populations of 32 species of shorebirds in which parents synchronize their schedules to achieve continuous incubation of the eggs, they show that even under similar environmental conditions and despite day-long environmental cues, social synchronization can generate far more diverse behavioural rhythms than expected from studies of captive birds. The risk of predation, not starvation, might be a key determinant of biorhythmic diversity. The behavioural rhythms of organisms are thought to be under strong selection, influenced by the rhythmicity of the environment1,2,3,4. Such behavioural rhythms are well studied in isolated individuals under laboratory conditions1,5, but free-living individuals have to temporally synchronize their activities with those of others, including potential mates, competitors, prey and predators6,7,8,9,10. Individuals can temporally segregate their daily activities (for example, prey avoiding predators, subordinates avoiding dominants) or synchronize their activities (for example, group foraging, communal defence, pairs reproducing or caring for offspring)6,7,8,9,11. The behavioural rhythms that emerge from such social synchronization and the underlying evolutionary and ecological drivers that shape them remain poorly understood5,6,7,9. Here we investigate these rhythms in the context of biparental care, a particularly sensitive phase of social synchronization12 where pair members potentially compromise their individual rhythms. Using data from 729 nests of 91 populations of 32 biparentally incubating shorebird species, where parents synchronize to achieve continuous coverage of developing eggs, we report remarkable within- and between-species diversity in incubation rhythms. Between species, the median length of one parent’s incubation bout varied from 1–19 h, whereas period length—the time in which a parent’s probability to incubate cycles once between its highest and lowest value—varied from 6–43 h. The length of incubation bouts was unrelated to variables reflecting energetic demands, but species relying on crypsis (the ability to avoid detection by other animals) had longer incubation bouts than those that are readily visible or who actively protect their nest against predators. Rhythms entrainable to the 24-h light–dark cycle were less prevalent at high latitudes and absent in 18 species. Our results indicate that even under similar environmental conditions and despite 24-h environmental cues, social synchronization can generate far more diverse behavioural rhythms than expected from studies of individuals in captivity5,6,7,9. The risk of predation, not the risk of starvation, may be a key factor underlying the diversity in these rhythms.

ABSTRACTAmerican peregrine falcons (Falco peregrinus anatum) throughout North America declined following the introduction of dichlorodiphenyltrichloroethane (DDT) in 1947. In the 1960s, intensive studies were initiated in many areas of North America, including interior Alaska, to determine the cause of the decline and assess population status. From 1977 to 2015, we studied peregrine falcons along a 265‐km section of the upper Yukon River in east‐central Alaska. We counted occupied territories, documented breeding success and productivity, and collected unhatched eggs for contaminant analysis. We observed 1,602 occupied territories and 2,349 nestlings. Annual breeding success averaged 64%, and annual productivity averaged 1.54 nestlings/territory and 2.38 nestlings/successful territory. Annual rates of increase in the number of occupied territories were greatest in the late 1970s and 1980s (8.6%), moderate in the 1990s (2.8%), and least in the 2000s (1.5%). Reproductive metrics were highest in the late 1970s and 1980s, declining in recent years. As the number of occupied territories increased (14–60) and average nearest neighbor distance decreased (from 9.8 km to 2.6 km), breeding success declined (from 71% in the 1980s to 57% in the 2000s). Productivity, as measured by nestlings per occupied territory, declined (from 1.84 in the 1980s to 1.29 in the 2000s). Nestlings per successful territory also declined from 2.56 in the 1980s to 2.25 in the 2000s. Survey data for 1966–2015 reveal a declining population in the 1960s and early 1970s, increasing in the late 1970s through the early 2000s, and apparently stabilizing in recent years. The recovery of this local population took roughly 40 years, from a low of 12 occupied territories in early 1970s to 60 in 2012–2014. Importantly, the recovery of American peregrine falcons in Alaska occurred without captive breeding, releases, or nest site manipulations. Long‐term studies are essential in fully understanding the biology of any species, and this study provides insight into the unaided, natural recovery of American peregrine falcons in Alaska. © 2016 The Wildlife Society.

As ancestral biodiversity responded dynamically to late‐Quaternary climate changes, so are extant organisms responding to the warming trajectory of the Anthropocene. Ecological predictive modeling, statistical hypothesis tests, and genetic signatures of demographic change can provide a powerful integrated toolset for investigating these biodiversity responses to climate change, and relative resiliency across different communities. Within the biotic province of Beringia, we analyzed specimen localities and DNA sequences from 28 mammal species associated with boreal forest and Arctic tundra biomes to assess both historical distributional and evolutionary responses and then forecasted future changes based on statistical assessments of past and present trajectories, and quantified distributional and demographic changes in relation to major management regions within the study area. We addressed three sets of hypotheses associated with aspects of methodological, biological, and socio‐political importance by asking (1) what is the consistency among implications of predicted changes based on the results of both ecological and evolutionary analyses; (2) what are the ecological and evolutionary implications of climate change considering either total regional diversity or distinct communities associated with major biomes; and (3) are there differences in management implications across regions? Our results indicate increasing Arctic richness through time that highlights a potential state shift across the Arctic landscape. However, within distinct ecological communities, we found a predicted decline in the range and effective population size of tundra species into several discrete refugial areas. Consistency in results based on a combination of both ecological and evolutionary approaches demonstrates increased statistical confidence by applying cross‐discipline comparative analyses to conservation of biodiversity, particularly considering variable management regimes that seek to balance sustainable ecosystems with other anthropogenic values. Refugial areas for cold‐adapted taxa appear to be persistent across both warm and cold climate phases and although fragmented, constitute vital regions for persistence of Arctic mammals.

Evaluering af Arktisk Biodiversitet har modtaget okonomisk stotte fra folgende kilder: Canada, Danmark/Gronland, Finland, Norge, Sverige, USA og Nordisk Ministerrad, og den ledende forsker er blevet finansieret af Miljostyrelsen, Danmark, som en del af miljostotteordningen DANCEA.

Climate change in the Arctic is a growing concern for natural resource conservation and management as a result of accelerated warming and associated shifts in the distribution and abundance of northern species. We introduce a predictive framework for assessing the future extent of Arctic tundra and boreal biomes in northern Alaska. We use geo-referenced museum specimens to predict the velocity of distributional change into the next century and compare predicted tundra refugial areas with current land-use. The reliability of predicted distributions, including differences between fundamental and realized niches, for two groups of species is strengthened by fossils and genetic signatures of demographic shifts. Evolutionary responses to environmental change through the late Quaternary are generally consistent with past distribution models. Predicted future refugia overlap managed areas and indicate potential hotspots for tundra diversity. To effectively assess future refugia, variable responses among closely related species to climate change warrants careful consideration of both evolutionary and ecological histories.

The Arctic Biodiversity Assessment has received financial support from the following sources: Canada, Denmark/Greenland, Finland, Norway, Sweden, United States of America, the Nordic Council of Ministers, and the Chief Scientist was financed by the Danish Environmental Protection Agency as part of the environmental support programme DANCEA.