Comparison Of Bird Communities Across An Edge-Interior Gradient In A Secondary Forest At Houmiling, Hainan Island, China

Fragment habitats have increased after deforest and resulted in various edge habitats. Edge habitat has seriously impacted on forest bird community. To understand edge effects on bird community in a second-growth tropical rainforest, we examined how forest bird communities and different guilds change from the edge to the interior of the secondary forest at Houmiling Nature Reserve, Hainan from August2010to September2012. Point counts and mist netting were used to survey birds at three sampling bands:0-100m (Edge band),100-300m (Intermediate band) and300-500m (Interior band) from forest edge.A total of93species were recorded including83species recorded by point counts and51species recorded by mist net. Total capture rate was1.2species/100net-hours and11.2individuals/100net-hours. The results of sample-based rarefaction curves illustrated the completeness of point count inventories and the sufficiency of sampling efforts, but the curves of mist net data indicated that sampling efforts were still inadequate. Hence my statistical analyses were mainly based on data from point count surveys. There was significant difference among the three sampling bands for mean species richness per point (χ2=21.60, df=2,P<0.001), and also significant difference for mean individual number per point(χ2=9.05, df=2, P=0.011). Multiple comparisons revealed that species richness and individual abundance was highest in intermediate band (100-300m) and lowest in edge band (0-100m). Additionally, bird species diversity was lowest in edge band. Those results show that edge of second-growth tropical rainforest had negative effects on bird community.Species composition significantly differed from the edge band to interior band. Edge band harboured more open-habitat users, as well as a great number of omnivores, granivores, ground insectivores, shrub insectivores and carnivores, for example, Light-vented Bulbul (Pycnonotus sinensis) and Spotted Dove (Streptopelia chinensis), Oriental Magpie Robin (Copsychus saularis), Greater Coucal (Centropus sinensis), and Common Kingfisher (Alcedo atthis), those species had an edge-preferring response. Intermediate and interior bands supported more forest-dependent species and forest generalists, those guilds were composed of frugivores, nectarivores and insectivores, such as Grey-cheeked Fulvetta (Alcippe morrisonia), Fork-tailed Sunbird (Aethopyga christinae) and Puff-throated Bulbul (Alophoixus pallidus), which were sensitive to forest edge, showing significant avoidance to the edge. In conclusion, the creation of forest edge have negative effects on the bird diversity on Hainan Island, those findings are helpful for the conservation of forest bird and the habitat management.