Effect of Yami forest management on spider diversity on Orchid Island, Taiwan.
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 Yami people forest management are assessed by comparing the spider diversity in four types of habitats receiving different degrees of managements. 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, I measured vegetation structure and prey availability to identity possible factors responsible for the observed differences in spider diversity. Analysis of Similarities was used to quantify the degree of overlap in the Bray-Curtis similarity between sampling plots. 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. Canopy cover and the structural complexity of understory plants differed significantly among habitats. 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 forest management activities of the Yami people increase spider diversity on Orchid Island by generating habitat types with different vegetation physical structures.
Updated: Mar-10-2014 01:22:51 (Taiwan, GMT+08:00).