Roost selection of the endangered Spotted Greenshank (Tringa guttifer) in critical habitat in the Inner Gulf of Thailand

Chenxing Yu,Philip D Round,Andrew J Pierce,Dusit Ngoprasert,Tommaso Savini,George A Gale

doi:10.1186/s40657-019-0148-7

Chenxing Yu, Philip D Round + Show 4 more

Open Access

https://doi.org/10.1186/s40657-019-0148-7

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Abstract

BackgroundRoost-site quality can significantly affect the individual fitness of shorebirds, but roost sites remain poorly described for many threatened species on the East Asian–Australasian Flyway. We studied roost-site selection of the globally endangered Spotted Greenshank (Tringa guttifer) in the Inner Gulf of Thailand, an area which supports approximately 24% of their global wintering population, during two non-breeding seasons (October 2014–May 2015 and December 2015–February 2016).MethodsWe measured nine variables associated with roost site characteristics including water depth, indicators of disturbance/predation risk, and associations with other shorebird species. We predicted that roost ponds with shallow water in proximity to foraging sites would receive higher usage than those further away.ResultsA total of 94 sites were measured of which 46 were used for roosts with 23 used repeatedly. All used sites were human-modified ponds, of which 44 were used for salt farming and two used for aquaculture. Roosts were on average 1.10 ± 0.78 (SE) km from foraging sites and 5.8 ± 2.4 cm deep. The most supported model indicated that roost sites were negatively associated with distance to foraging sites and positively associated with the presence of Grey Plover (Pluvialis squatarola) and water depth.ConclusionsTraditional saltpans and other artificial wetlands near (< 1 km) mudflats serve as the primary high-tide roost habitat in the Inner Gulf of Thailand for this Spotted Greenshank population and perhaps seven other globally threatened or near-threatened species. Critically, all observed roost sites are on private land with no formal protection and thus will require creative public–private partnerships to manage sustainably.

Highlights

Roost-site quality can significantly affect the individual fitness of shorebirds, but roost sites remain poorly described for many threatened species on the East Asian–Australasian Flyway
The roost habitat selection of Spotted Greenshanks was determined by the tide cycle
Our models predicted that water depth, distance to nearest foraging sites and interactions with specific species were the main factors associated with roost selection of Spotted Greenshanks among our three main sites in the Inner Gulf of Thailand

Summary

Introduction

Roost-site quality can significantly affect the individual fitness of shorebirds, but roost sites remain poorly described for many threatened species on the East Asian–Australasian Flyway. While there has been considerable recent research on the status and conservation of foraging sites (Yang et al 2011; Murray et al 2014; Bai et al 2015; Hua et al 2015; Moores et al 2016; Lee et al 2017; Pearce-Higgins et al 2017; Peng et al 2017), non-breeding roosting sites have received less attention but may be important, as intertidal foraging areas may become underused or inaccessible to shorebirds if suitable roosts are unavailable (Rogers 2003). Understanding the characteristics of roost use by wintering shorebirds may help judge whether roosting habitat could be a limiting factor either for key shorebird species or important staging sites

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