台灣中部能高越嶺道五種不同植被類型蜘蛛多樣性之比較

Abstract

能高越嶺道橫跨中央山脈，海拔約1600～2900 m，全線具有多樣的植被類型，可作為探討中、高海拔山區不同植被類型蜘蛛組成與多樣性之比較，及其可能形成原因。本研究選取松－闊葉樹混淆林（PH）、松林（P）、鐵杉－闊葉樹混淆林（HH）、鐵杉－冷杉混淆林（HF）及草原（G）五種植被類型作為研究區域。每種植被類型各設置8個5 m × 5 m的樣區，總共有40個樣區，再以掉落式陷阱及掃網兩種方法，分別調查樣區內地表及灌叢活動的蜘蛛。本研究從2010年3月起至2011年3月止，除了2010年7月及2011年2月因氣象因素外，每月調查一次，合計共紀錄蜘蛛28科159種9155隻，包括成蛛2847隻，若蛛6308隻。其中掃網調查共紀錄112種6565隻蜘蛛，掉落式陷阱為65種2590隻。ANOVA分析結果顯示不同植被類型間蜘蛛群落結構有顯著差異：P、PH及HH的Shannon index顯著高於G及HF；HF的Simpson index則顯著高於PH、P及HH；HH的Evenness index顯著高於HF。各植被類型蜘蛛群落結構的差異似乎可反映彼此間植被結構與覆蓋度的差異。利用兩兩樣區間之Euclidean distance進行的群聚分析，顯示所有樣區可區分為三群，分別是森林群（Forest group）、草原群（Grassland group）與混合群（Mixed group），屬於同一群的樣區通常有相似的環境與蜘蛛物種組成。本研究成果可作為日後環境監測的參考。

The Nengkao Cross Mountain Trail (NCMT) is a part of the high mountain hiking trail system of Taiwan that connects Hualien and Nantou Counties by crossing the Central Mountain Range at elevation ranged about 1600-2900 m above the sea level. The environment along the NCMT includes many sorts of vegetation types that provide a chance for us to study the spider biodiversity among different types of vegetation.We chose five different vegetation types along the NCMT for sampling, including the mixed pine-hardwood forest (PH), pine forest (P), mixed hemlock-hardwood forest (HH), mixed hemlock-fir forest (HF), and grassland (G). Eight 5×5 m sampling plots in each vegetation type were settled, and both the pitfall trap and sweeping net methods were used for sampling spiders from March 2010 to March 2011 (except for July 2010 and February 2011) once per month. A total of 9155 spiders belonging to 159 species in 28 families were caught, including 2847 adults and 6308 juveniles. Among them, 6565 spiders belonging to 112 species were captured by sweeping, and 2590 spiders belonging to 65 species were captured by pitfall traps. The structure of spider communities was significantly different among vegetation types. The Shannon index of P, PH and HH are significantly higher than those of G and HF. Contrarily, the Simpson index of HF is significantly higher than those of PH, P and HH. The Evenness index of HH is significantly higher than that of HF. The result of cluster analysis by using the pair-wised Euclidean distance shows that all the sampling plots can be divided into three main clusters, i.e., the forest, grassland and mixed groups. Plots of the same cluster always share a similar environment and the spider composition. Results of the present study can be used for further environmental monitoring in the higher mountains of Taiwan.