關刀溪非繁殖季鳥類同功群之研究

Guild Structure of the Guandaushi Avian Community in Non-breeding Seasons

本研究從1995年10月至1997年12月，以點估法，以及霧網捕捉法對關刀溪森林生態系內鳥類同功群進行系統性的研究。主要目的在於探討並分析分佈於台灣中低海拔森林生態系內鳥類同功群之結構，進一步以鳥類同功群為單位，分析鳥類對森林資源的使用模式；以利於探討環境變化對鳥類群聚的影響。LTER樣區內觀察到42種鳥，從各種鳥類之食性與覓食之基質，可以進一步將42種鳥類歸入12種不同的鳥類同功群（Avian Guilds）。各種鳥類之族群密度由每ha 0.25隻到75.75隻不等，而繡眼畫眉（Alcippe morrisonia）為研究區內之優勢種。同功群中以活躍於灌叢中覓食昆虫之個體總數最多，在整個生態體系中，由單位面積內，同功群之個體數量以食虫性鳥類佔總數量之79.2%可以看出，昆蟲數量為維繫整個鳥類群聚之重要因子。各同功群之鳥種豐度，以在底層活動，以昆蟲為食物之同功群（IB）最為豐富。IB和IM（在樹林中層活動，以昆蟲為食物）為兩種結構特徵上不同極端的同功群，IB同功群具極高度的不均勻性。而IM同功群則具極高度的均勻性。由林相來看，杉木（Cunninghamia lanceolata）造林地鳥群具之豐度最為貧乏。人造針葉林之（值較闊葉樹林為低，但具較高的均勻度。此結果顯示在闊葉林中，有明顯的優勢鳥種影響群聚之結構。在各種植群中，以日本扁柚（Chamaecyparis obtusa）林型（C）鳥群眾之豐度最高，而反刺儲（Castanopsis eyrei）– 臺灣黃杞（Engelhadtia roxburghiana）（E6）最為貧乏，鳥群異質性很高，每一植群中皆有一兩種數目較多之優勢種。分析11個同功群，只有IB同功群之平均鳥密度在不同林相內有顯著的差異而同功群FU和IB之平均密度在不同植群內有顯著的差異。 A systematic study of avian guild was conducted at Guandaushi LTER site with point count and mist net capture methods from October 1995 to December 1997. The main purpose of this study was to identify and analyze the structure of various avian guilds found in the forest ecosystems located at the middle and low elevations of Taiwan. Another purpose of this study was to apply the guild concept on the analysis of avian resource utilization patterns in order to evaluate the impacts of environment changes on bird community. We identified 42 avian species with 12 avian guilds during the study period. Each species was assigned to one of the 12 guilds according to its trophic patterns and feeding substrates. The average population density of birds ranged from 0.25 to 75.75 per hectare. Alicppe morrisonia was the dominant species of the ecosystem. The guild representing birds foraging on insect among bushes (IB) was the most abundant among the guilds. A 79.2% of birds counted was identified as insect eating birds in the ecosystem. Therefore, insect was the main food sources for the avian community at Guandaushi forest ecosystem. The species richness of IB guild was the greatest among the 14 guilds. The community structure in term of species richness, species diversity and species evenness varied among guilds. Guild JB and IM (birds foraging on insect at the middle section of a tree) represented the two extreme community structures of the 14 guilds. The IB guild is a heterogeneous community, while IM is a homogenous community. The community structure of bird found in different forest types and vegetation patterns varied. Cultivated china fir (Cunninghamia lanceolata) holds less bird species than the other forest types. The (values of cultivated forests were lower than the (value of hardwood forest. However, the evenness indices of community in cultivated forests were greater than the evenness index of community from hardwood forest. Dominant bird species was found in hardwood forest to influence the community structure. The species richness of avian community in Japanese cypress (chamascyparis obtusa) (vegetation type C) was the greatest among the 6 different vegetation types. Guilds IB and FU were found highly selective for their habitats among different vegetation types.

A systematic study of avian guild was conducted at Guandaushi LTER site with point count and mist net capture methods from October 1995 to December 1997. The main purpose of this study was to identify and analyze the structure of various avian guilds found in the forest ecosystems located at the middle and low elevations of Taiwan. Another purpose of this study was to apply the guild concept on the analysis of avian resource utilization patterns in order to evaluate the impacts of environment changes on bird community. We identified 42 avian species with 12 avian guilds during the study period. Each species was assigned to one of the 12 guilds according to its trophic patterns and feeding substrates. The average population density of birds ranged from 0.25 to 75.75 per hectare. Alicppe morrisonia was the dominant species of the ecosystem. The guild representing birds foraging on insect among bushes (IB) was the most abundant among the guilds. A 79.2% of birds counted was identified as insect eating birds in the ecosystem. Therefore, insect was the main food sources for the avian community at Guandaushi forest ecosystem. The species richness of IB guild was the greatest among the 14 guilds. The community structure in term of species richness, species diversity and species evenness varied among guilds. Guild JB and IM (birds foraging on insect at the middle section of a tree) represented the two extreme community structures of the 14 guilds. The IB guild is a heterogeneous community, while IM is a homogenous community. The community structure of bird found in different forest types and vegetation patterns varied. Cultivated china fir (Cunninghamia lanceolata) holds less bird species than the other forest types. The (values of cultivated forests were lower than the (value of hardwood forest. However, the evenness indices of community in cultivated forests were greater than the evenness index of community from hardwood forest. Dominant bird species was found in hardwood forest to influence the community structure. The species richness of avian community in Japanese cypress (chamascyparis obtusa) (vegetation type C) was the greatest among the 6 different vegetation types. Guilds IB and FU were found highly selective for their habitats among different vegetation types.