中心館藏網址 http://tulips.ntu.edu.tw/record=b2174072*cht

[ 摘要 ]
熱帶森林擁有豐富的蜘蛛多樣性，但相關研究大多針對溫帶地區的農地生態系，並著重在調查底棲性的蜘蛛群落。位於台灣東南的蘭嶼島，是東亞地區熱帶森林分佈之北限。本研究旨在探討蘭嶼熱帶森林的蜘蛛多樣性，並以原住民之各種棲地利用所形成不同棲地類型間之比較為主軸，針對蘭嶼生態系中森林內部、草原以及兩者的過渡區域(森林邊緣)三種不同棲地類型，選定四個重複樣區（永興、永興外、野銀、中興）作為比較。我們在每個樣區設置四個5m ×5m的採樣點共48個，另於較原始的天池森林，設置兩個樣區共8個採樣點。其中，天池以外的樣區因離部落較近，受到相當程度的人為干擾，而天池所受干擾則相對低上許多。採集共使用掉落式陷阱、玻利式漏斗、灌叢掃網、徒手日、夜間採集及樹冠層撈網等六種方法，在每個採樣點系統性採集由地表至10公尺高度樹冠層之所有蜘蛛。在2000及2001年之間所進行的三次採集共獲得蜘蛛共5406個體，包含2845隻成體，分屬19科150個種。以ANOVA分析四種類型棲地間之群落結構，結果顯示不同棲地間之蜘蛛群落結構有相當顯著之差異；而種類組成及功能群之比較之分析結果亦是如此。這些結果顯示森林內部採樣點無論在物種數及多樣性指數皆顯著高於草原採樣點。而有小尺度原住民砍伐之森林採樣點之物種數及部分多樣性指數反高於位於天池原始林之採樣點。比起前者，後者之優勢物種所佔比例高出許多。利用兩兩採樣點間之Euclidean distance所進行之Clustering analysis顯示所有採樣點可區分為森林及草原等兩大類型，顯示兩種棲地類型之物種組成有極大差異。此外，樹冠層較茂密的林邊樣點被歸在森林類型，而樹冠較稀疏的樣點則被歸在草原類型，顯示蜘蛛群落對棲地有一定的偏好，並隨棲地品質有有所變化。在分層比較樹冠、灌叢與地表之蜘蛛多樣性時發現，灌叢之種豐富度與數量最為豐富；而且三者的群落結構與功能群組成均有顯著差異，顯示蜘蛛群落主要的分佈範圍在兩公尺以下的區域且受微棲地所影響。研究結果顯示，蘭嶼熱帶森林生態系擁有相當高且獨特的蜘蛛多樣性。雅美人對森林內部之傳統利用模式似乎可藉降低優勢種之比例而維持較高之蜘蛛多樣性。但若將森林完全砍伐形成草原後，蜘蛛之多樣性將降低，且其種類組成與群落結構將完全改觀。
[ 英文摘要 ]
Tropical forests exhibit very high spider diversity, but most related studies examined a particular functional group or layer of the habitat and few assessed the impacts of disturbance on tropical Araneae diversity. Orchid Island is 40 sea miles off the southeast coast of Taiwan and her forests are the northern most tropical forests in East Asia. In this study, the spider diversity of Orchid Island was studied and those from three types of habitats generated by various kinds of aboriginal activities were compared. Habitat types examined in this study included the forest, the meadow and the forest edge. All habitat types had four replicates each containing four 5m×5m sampling plots. In addition, we also set up additional 8 plots in the relatively undisturbed primary forest in Tienchi for comparison. Spiders from the ground, understory shrubs and canopy were collected to have a comprehensive representation of diversity from all microhabitats in the sampling plots. From the adult specimens obtained, a total of 150 species from 19 families were identified. The composition and structure of spider communities were significantly different between different habitats. Plots in the forest habitats exhibited significantly higher species richness and diversity than those in the meadow. Compared with plots in the forest habitats, those in the Tienchi primary forest had lower species richness and diversity due to overrepresentation of dominant species. Result of a UPGMA analysis using pair-wise Euclidean distance demonstrated that most of the sampling plots could be clustered into two major groups, Forests and Meadows. Plots of forest edge habitats exhibiting less canopy cover were grouped with the meadow plots and those with more canopy cover were grouped with the forest plots. Foraging guild composition also differed significantly among types and layers of the habitats. Results of this study suggest that while clear-cutting of the forest generated a distinct spider community, limited scale of logging by local people seemed to increase the diversity of spiders by suppressing the dominant specie