A comparison of spider diversity between natural and artificial aquatic habitats on Orchid Island, Taiwan. (1/2) (NSC 91-2621-B-029-004)


Spiders are ubiquitous predators in terrestrial ecosystems. Spider abundance and diversity are found to be significantly correlated with many environmental parameters. Moreover, by comparing the abundance of dominant species between different localities, the habitat preference of spiders can be inferred. In the past, studies on aquatic habitats in tropical areas are few and the studies of the effects of human disturbances are even fewer. In this study, I investigate the spider diversity in aquatic habitats on Orchid Island, Taiwan to realize the effects of human disturbances on diversity of aquatic habitats. Orchid Island is a tropical island off the southeast coast of Taiwan and the aboriginals, Yami people, are of Austranesican origin. Similar to other Austranesican aboriginals, Yami people use taro as one of the major crops. The effected of taro plantation on biodiversity is unclear and the spider diversity may be different from that of streams. Another human disturbance is construction of dikes in streams, which may exhibit significant effect on biodiversity. The study sites included the Ye-yu and Hung-tou streams both located on west Orchid Island and each exhibited both natural and artificial aquatic habitats. Specimens were collected using pitfall traps, visual search, sweeping net, canopy sweeping net and beating. From the field trip conducted in October 2002 141adult and 220 juvenile specimens were obtained. Results of preliminary analyses on those specimens showed that taro plantation do not seem to reduce spider diversity and abundance. Construction of dike greatly reduces spider diversity and abundance, but introducing vegetation may limitedly recover the fauna. Sampling plots in two streams have similar guild composition but different species composition. This result suggests that each stream exhibits a unique any of species and should be considered in the management water ways.

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Updated: Jan-24-2014 11:34:24 (Taiwan, GMT+08:00).