Carex spp).
Finally, the most suitable habitats had higher land productivity heterogeneity (Fig. 5E and 5H) which was expected as species richness and abundance often increases with habitat diversity (Chasko and Gates 1982; Wen et al. 2015). Although human disturbance can sometimes increase diversity in such wetland systems, here the habitat suitability decreases with human disturbance (Fig. 5F), reflecting the negative impacts of human presence (Lei et al. 2019b).

Conservation challenges

The results of this study highlight a major challenge from future climate change on the A. erythropus . First, many climate change models predict increasing spring temperatures and earlier snow melting (IPCC 2014), which will lead to flooding, submergence, permafrost erosion and loss and change in low-lying coastal wetlands (Prowseet al . 2006). As the predicted summering habitats were concentrated in the lowland coastal zone of the Laptev and East Siberian Seas, the projected sea level rise (IPCC 2014; Wrona et al . 2016) and increasing river flows (Karlsson et al . 2012; Wrona et al . 2016) could cause extensive habitat loss. The response curves of habitat suitability to topographic variables suggest that the relatively hilly and rugged landscape would restrict extension of suitable habitat landward and such “habitat squeeze” (Leo et al . 2019) would be highly detrimental to A. erythropus . Second, the models suggested that there was an “optimal window” in terms of mean summer temperature and precipitation, which could be interpreted as the realized climatic niche of A. erythropus (Merow et al . 2016). Rising temperatures under future climate change scenarios means that the temperature niche could shift northerly, which is sea. Third, studies have shown that encroachment of shrubs following projected climate change (e.g. Salix ovalifolia and Dushecia fruticosa ) into the wet meadows (Carlson et al . 2018), would likely decrease quantity and quality of available food resources.
Finally, there is the threat from increasing anthropogenic disturbance;A. erythropus avoids locations near active mines (although can colonize such areas after mining is finished) (Egorov and Okhlopkov 2007; Solovieva and Vartanyan 2011). Currently, human population levels in the predicted summering range is among the lowest in the world, and the coastal areas of this region are some of the least explored. However, the coast of the Russian Arctic is likely to undergo rapid development as there are reserves of oil, gas, metals and other natural resources which could be exported, with additional infrastructure, through the North-East Passage to European and Asian ports (Martiniet al . 2019), more information on these potential developments can be found athttp://ecoline-eac.com/proekty/peschanka/deposit.html ), and these developments present perhaps the most difficult challenges to the future of eastern sub-population of A. erythropus .