Modelling the potential non-breeding distribution of Spoon-billed Sandpiper Calidris pygmaea

Tom Bradfer-Lawrence,Qing Chang,Sayam U Chowdhury,Christoph Zockler,Rhys E Green,Nigel A Clark,Guy Q A Anderson,Graeme M Buchanan,Pyae Phyo Aung,Evgeny E Syroechkovskiy,Jing Li,Elena G Lappo,Baz Hughes,Pavel S Tomkovich,Alison E Beresford,Geoff M Hilton,Yuri N Gerasimov

doi:10.1017/s0959270920000398

Abstract

SummaryThe Spoon-billed Sandpiper Calidris pygmaea is a ‘Critically Endangered’ migratory shorebird. The species faces an array of threats in its non-breeding range, making conservation intervention essential. However, conservation efforts are reliant on identifying the species’ key stopover and wintering sites. Using Maximum Entropy models, we predicted Spoon-billed Sandpiper distribution across the non-breeding range, using data from recent field surveys and satellite tracking. Model outputs suggest only a limited number of stopover sites are suitable for migrating birds, with sites in the Yellow Sea and on the Jiangsu coast in China highlighted as particularly important. All the previously known core wintering sites were identified by the model including the Ganges-Brahmaputra Delta, Nan Thar Island and the Gulf of Mottama. In addition, the model highlighted sites subsequently found to be occupied, and pinpointed potential new sites meriting investigation, notably on Borneo and Sulawesi, and in parts of India and the Philippines. A comparison between the areas identified as most likely to be occupied and protected areas showed that very few locations are covered by conservation designations. Known sites must be managed for conservation as a priority, and potential new sites should be surveyed as soon as is feasible to assess occupancy status. Site protection should take place in concert with conservation interventions including habitat management, discouraging hunting, and fostering alternative livelihoods.

Highlights

The Spoon-billed Sandpiper Calidris pygmaea is a Critically Endangered calidrid found in Asia (BirdLife International 2017)
The high AUC values signified that all four models were adequate descriptions of Spoon-billed Sandpiper distributions (Table 2)
This indicates that the predicted outputs could be accurate representations of potential Spoon-billed Sandpiper distributions

Summary

Introduction

The Spoon-billed Sandpiper Calidris pygmaea is a Critically Endangered calidrid found in Asia (BirdLife International 2017). Demographic studies indicate an unusually low per capita recruitment of two-year old adults to the breeding population, while other demographic rates are similar to those of other small calidrids (Zockler et al 2010a) This finding suggests that the major external drivers of the population decline are factors affecting the mortality rate of immature birds, such as loss of intertidal habitat at migration stopover sites and hunting on the wintering grounds (Zockler et al 2010b, 2016, Chowdhury 2012, Tong et al 2012, Piersma et al 2016, Peng et al 2017, Choi et al 2018). There have already been some successful conservation interventions, discouraging hunting at known sites (Bird et al 2010, Clark et al 2014, Zockler et al 2016)

Methods

Results

Discussion

Conclusion