Rapid population decline in migratory shorebirds relying on Yellow Sea tidal mudflats as stopover sites

Colin E Studds,Nicholas J Murray,Ken Gosbell,Hugh P Possingham,Bruce E Kendall,David A Milton,Richard A Fuller,Howard B Wilson,Clive D T Minton,David S Melville,Rosalind Jessop,Adrian C Riegen,Robert S Clemens,Chris J Hassell,Eric J Woehler,Danny I Rogers,Phil Straw

doi:10.1038/ncomms14895

Abstract

Migratory animals are threatened by human-induced global change. However, little is known about how stopover habitat, essential for refuelling during migration, affects the population dynamics of migratory species. Using 20 years of continent-wide citizen science data, we assess population trends of ten shorebird taxa that refuel on Yellow Sea tidal mudflats, a threatened ecosystem that has shrunk by >65% in recent decades. Seven of the taxa declined at rates of up to 8% per year. Taxa with the greatest reliance on the Yellow Sea as a stopover site showed the greatest declines, whereas those that stop primarily in other regions had slowly declining or stable populations. Decline rate was unaffected by shared evolutionary history among taxa and was not predicted by migration distance, breeding range size, non-breeding location, generation time or body size. These results suggest that changes in stopover habitat can severely limit migratory populations.

Highlights

Migratory animals are threatened by human-induced global change
After accounting for the shared evolutionary history among taxa, we found that Yellow Sea reliance was the single most important predictor of variation in population trends (Fig. 1a)
(slope 1⁄4 À 0.92, 95% credible interval (CRI) 1⁄4 À 1.25, À 0.59; Fig. 1b), indicating that long-term population declines were greatest for taxa that depend more heavily on refuelling stops in this region (Table 1; Fig. 2)

Summary

Introduction

Migratory animals are threatened by human-induced global change. little is known about how stopover habitat, essential for refuelling during migration, affects the population dynamics of migratory species. The Yellow Sea region is a migration bottleneck for many EAAF shorebirds, species vary in their reliance on migratory stopover sites in this area. We measure abundance and population trends for ten EAAF shorebird taxa for which expert-defined migratory connectivity networks were available[22] to test if taxa that rely heavily on Yellow Sea tidal mudflats to stage their long-distance migrations are experiencing the most rapid population declines.

Results

Conclusion