農業生態系統中多樣土地覆蓋類型的鳥類多樣性

Abstract

農業開發是生物多樣性流失的主要原因之一，然而高空間異質度的農村地景卻可能成為保育生物多樣性的潛在區域。複雜且破碎的農村地景有較高的棲地邊緣比例，但各土地覆蓋類型是否存在邊緣效應，其是否受相鄰棲地的外溢者影響，皆為了解農村地景生物多樣性的基礎資訊。探究農村地景中各土地覆蓋類型的生物多樣性、邊緣效應和相鄰土地覆蓋類型對生物多樣性的影響，並將功能多樣性納入討論，對生態保育和土地規劃至關重要。本研究於2021年4月至2023年4月在南投縣竹山鎮、水里鄉、信義鄉和鹿谷鄉，選定8種土地覆蓋類型，設置67組樣帶，共402個樣區，調查樣區內的鳥類個體數和物種數。結果顯示多數土地覆蓋類型的鳥種組成有顯著差異，代表各土地覆蓋類型皆有其特色物種。次生林的物種多樣度多顯著高於其他土地覆蓋類型，然而其功能多樣度與其他土地覆蓋類型並無顯著差異。次生林、人工針葉林和竹林的邊緣效應較顯著，顯示次生林、人工針葉林和竹林在農村地景中有增加微棲地的功能。相鄰土地覆蓋類型間彼此的影響並沒有一致的趨勢，需要更多的研究才能了解相鄰土地覆蓋類型對鳥類多樣性的影響。於農村地景中規劃多樣的土地覆蓋類型，積極保留次生林、人工針葉林和竹林，或改善各土地覆蓋類型的現況，對鳥類多樣性和生態功能皆可發揮正面助益。

Agricultural development is a major driver of biodiversity loss. Nonetheless, some agricultural landscapes with high spatial heterogeneity can be a potential area to host biodiversity. The complex and fragmented agricultural landscapes increase the proportion of habitat edges. Therefore, exploring edge effect and spillover effect of each land cover types become fundamental for ecological conservation and land-use management of agroecosystems. This study was aimed to examine avian species diversity and functional diversity among different land cover types, distances to boundary and adjacent land cover types. The study was conducted in Lugu Township, Shuili Township, Xinyi Township and Zhushan Township of Nantou County, Taiwan, from April 2021 to April 2023. We counted all individual of birds and bird species seen and heard on the 402 plots of 67 belt transects in 8 land cover types. Each belt transect was consisted of 6 plots across two land cover types. We found the avian species composition of most land cover types differed significantly, indicating diverse land cover types is crucial for conserving avian diversity in agroecosystem. The species diversity of secondary forest was significantly higher than most land cover types; however, the functional diversity of secondary forest was not significantly higher than others. The edge effect can be observed in secondary forest, conifer plantation and bamboo forest, creating microhabitats for adjacent land cover types. However, the effect of adjacent land cover types to avian diversity was not significant and need more studies to confirm. Maintaining diverse land cover types, retaining more secondary forest, conifer plantation or bamboo forest, and improving habitat quality of all land cover types will be beneficial to avian species diversity and ecological function in agricultural landscapes.