A comparison of spider diversity between natural and artificial aquatic habitats on Orchid Island, Taiwan. (2/2) (NSC 92-2621-B-029-001)

Abstract

Orchid Island is 92 km off the southeast coast of Taiwan and its forests are the northernmost tropical forests in East Asia. In this study, the effects of habitat management by Orchid Island inhabitants, the Yami people, on biodiversity are assessed by comparing the spider diversity in four types of habitats receiving different degrees of disturbances. Habitat types examined in this study included natural forest, cultivated woodland, second growth and grasslands. All habitat types were replicated in the northern, eastern, and southern region of the island. Spiders were collected from the ground to canopy to obtain a comprehensive representation of the diversity from all layers of microhabitats in the sampling plots. In addition, we measured vegetation structure and prey availability to determine possible factors responsible for the observed differences in spider diversity. Species and guild composition did not vary with location on the island but differed significantly among habitats. The variation in spider diversity was correlated with variations in vegetation structures. Natural forests receiving the lowest level of disturbances had the most complex understory vegetation structure, but did not have the highest spider diversity. Cultivated woodland subjected to an intermediate level of disturbances exhibited a less complex understory vegetation structure, but a higher spider diversity. Spider diversity did not seem to be determined by prey availability, because insect biomass did not vary significantly among habitats. Results of this study suggest that the habitat management of the Yami people maintains a high spider diversity on Orchid Island by generating novel habitat types with different vegetation physical structures.

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