The Arctic is entering a new ecological state, with alarming consequences for humanity. Animal-borne sensors offer a window into these changes. Although substantial animal tracking data from the Arctic and subarctic exist, most are difficult to discover and access. Here, we present the new Arctic Animal Movement Archive (AAMA), a growing collection of more than 200 standardized terrestrial and marine animal tracking studies from 1991 to the present. The AAMA supports public data discovery, preserves fundamental baseline data for the future, and facilitates efficient, collaborative data analysis. With AAMA-based case studies, we document climatic influences on the migration phenology of eagles, geographic differences in the adaptive response of caribou reproductive phenology to climate change, and species-specific changes in terrestrial mammal movement rates in response to increasing temperature.

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.

Evaluation of the importance of different benthos communities as feeding sites for waders and waterfowl is not only fundamental for understanding feeding ecology, it also enables the prediction of the effects of habitat loss. However, detailed analyses of the importance of different benthos communities for waterbirds are scarce, particularly for the German Wadden Sea. In the early 1990s. backbarrier tidal flats of the East Frisian Wadden Sea were dominated by Lanice conchllega. To estimate the relevance of those flats for waterbirds during autumn migration 1994, number, distribution and food consumption of the 7 most abundant bird species on these flats (oystercatcher, curlew, dunlin, redshank, common gull, black-headed gull, herring gull) were investigated on 2 different types of L conchilega dominated flats (Lanice flat, Undulating flat). Spnng tide counts throughout 1994 showed maximum bird numbers during spring (maxlmum 56000 birds) and autumn migration (maximum 111 000 birds). Of the 7 species examined, 4 species (oystercatcher, curlew, redshank, common gull) used both flat types in higher densities than expected. Whereas common gulls preferred the Undulating flats, oystercatchers preferred the Lanice flats. The overall number of macrozoobenthos organisms varied between 3360 and 5520 m-2 on the Undulating flat, and between 8520 and 15 100 m-' on the Lanice flat. Correspondingly, the estimated biomass ranged from 67.6 to 142.3 g AFDW m-' and 128.4 to 337.2 g AFDW m-' (AFDW: ash free dry weight), respectively. Therefore, biomass was higher than in most other Wadden Sea areas. The most abundant species were Heteromastus filiformis, L. conchilega, Macoma ballhica and Mytilus edulis. The overall consumption of the 7 bird species studied (70% of all waterbirds present) decreased from 16.6 g AFDW m-2 in August to 12.3 g AFDW m-'in October. Assuming a similar consumption for the remaining 30% of the birds, overall consumption would have ranged between 17.6 and 23.7 g AFDW m-'. Due to the high biomass of the standing stock, relative consumptlon (5 2 to 13.7 %) was similar to other regions of the Wadden Sea. Only 3 species (oystercatcher, curlew, common gull) consumed between 78 and 93% of the overall consumption of the 7 species exam~ned Whereas waders mainly foraged on the accompanying fauna of the L. conchilega community, the bulk of the diet of gulls was L. conchilega itself. In general, food supply on L. conchilega dominated flats can be judged as favourable However, the possibility that food consumption could have been a l i m~t~n g factor, at least for some specles (e.g. oystercatcher), cannot be ruled out

No abstract

The study of stopover sites has received a lot of attention in avian ecology, being especially important for many long-distance migrants, some of which have to pause several times during migration. The survival of many migratory birds depends primarily on food availability at these stopovers. However, previous studies show that there is a lack of knowledge about site selection where migratory birds stop to refuel energy stores. In the present study, a Bayesian expert system has been used to incorporate environmental parameters, to determine their relationship with the presence of barnacle geese at stopover sites. Data on stopover sites was obtained from satellite-tracked barnacle geese (Branta leucopsis) for three different breeding populations in the Western Palearctic (i.e. Russian, Svalbard and Greenland). The results from the present study showed that the posterior probability of presence at the stopover sites obtained from the Bayesian model was close to one. Therefore, the Bayesian expert system detected the stopover sites of the geese correctly and can be used as a proper method for modelling the presence of barnacle geese at the stopover sites in the future. This study introduces a new method into movement ecology to identify and predict the importance of different environmental parameters for stopover site selection by migratory geese. This is particularly important from both a conservation and an agro-economic point of view with the goal of reducing possible conflicts between geese and agricultural interests.