Bird guild loss and its determinants on subtropical land-bridge islands, China

Zhifeng Ding,Huijian Hu,Kenneth James Feeley,Ping Ding

doi:10.1186/s40657-015-0019-9

Zhifeng Ding, Huijian Hu + Show 2 more

Open Access

https://doi.org/10.1186/s40657-015-0019-9

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Abstract

BackgroundThe guild concept is useful for understanding the community structure in a land-bridge island system, but most fragmentation studies have focused only on the importance of island area and isolation, other island attributes such as perimeter-area ratio (PAR) were overlooked or understudied.MethodsWe have adopted a guild approach to investigate the impacts of island attributes on bird guild richness on a set of 41 recently isolated land-bridge islands in the Thousand Island Lake (TIL), China.ResultsWe found insectivores had the largest number of species (34 species), followed by understory foraging guilds (28 species), omnivores (27 species) and canopy guilds (25 species). Furthermore, our data showed that migrants and residents responded equally to island area, insectivores and understory guilds were sensitive to island area but omnivores and canopy guilds were not very sensitive. Most guild richness was determined by island area, except for omnivores and canopy guilds.ConclusionsAlthough PAR or habitat diversity found to be important for bird species richness, our results highlight the importance of island area in maintaining bird diversity in fragmented island systems.

Highlights

The guild concept is useful for understanding the community structure in a land-bridge island system, but most fragmentation studies have focused only on the importance of island area and isolation, other island attributes such as perimeter-area ratio (PAR) were overlooked or understudied
We considered four factors other than island area and isolation that might influence the number of coexisting bird species: PAR, SI, plant species richness, habitat diversity
Our findings showed insectivores had the largest number of species (34 species), followed by understory foraging guilds (28 species), omnivores (27 species) and canopy guilds (25 species)

Summary

Introduction

The guild concept is useful for understanding the community structure in a land-bridge island system, but most fragmentation studies have focused only on the importance of island area and isolation, other island attributes such as perimeter-area ratio (PAR) were overlooked or understudied. Most fragmentation studies have focused only on the importance of patch area, which may not adequately explain the effects of fragmentation on habitat occupancy by birds (Helzer and Jelinski 1999). Patches of equal area may vary significantly in the amount of their area exposed to edges, which can have significant impacts on bird communities. Studies by Helzer and Jelinski (1999) found that perimeter–area ratio (PAR) was a more effective measure of habitat patch quality than patch area.

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