THE ECOLOGY AND CONSERVATION OF MIGRATORY SHOREBIRDS ALONG THE EAST ASIAN-AUSTRALASIAN FLYWAY

Abstract

Investigating the factors shaping the diversified patterns of habitat use and long-distance movements of migratory species is not only fundamental to understanding the ecology and evolution of migration, but also has direct conservation implications to more effectively preserving globally declining migrant populations. In my dissertation, I used coastal shorebirds as the focal species, and investigated how an ecological understanding in their habitat preferences, habitat quality, as well as migratory movement and migration strategies may inform conservation practices for these rapidly declining species at different scales.In Chapter 1, I quantified the spatiotemporal distribution patterns of local shorebird populations, and found that the upper tidal flats provided more than 70% of the cumulative foraging time for most shorebird populations, disproportionately greater than the size of this stretch of tidal flat. The results could explain why the population decline rates of many shorebird species have far exceeded the overall rate of tidal habitat loss, highlighting the importance of protecting upper tidal flats for the conservation of migratory shorebirds. In Chapter 2, I devised an entirely field-based approach to quantitatively evaluate the quality of a major stopover site for the declining Red Knot. I estimated that the Nanpu tidal flat was operating below, but remarkably close to, its carrying capacity. This approach needs to be applied more broadly to more accurately evaluate how the Red Knot population may respond to changes in habitat quality. In Chapters 3 and 4, I tracked the annual migration of two small shorebird species, Red-necked Stint and Red-necked Phalaropes, using light-level geolocators. Tracking the annual movement of migratory species not only sheds light on the species-specific migration patterns, but also contributes to understanding the factors shaping migration strategies and the vulnerability of these strategies to different anthropogenic threats. Taken together, this dissertation investigated some of the key ecological questions regarding the migration and stopover ecology of migratory, with direct conservation implications in identifying the factors that affect the vulnerability of migratory species to various anthropogenic threats at different scales.