過去一個世紀以來,資源經營與生物多樣性保育之間常有許多衝突。人類長期經 營與利用森林資源的結果,造成地景的破碎與天然林的大量減少,此一現象,使長久以來習 用之森林經營方式與政策受到大眾的質疑,現有森林經營方式也必須因應此一變化而有所調 整。 因此,研究森林經營對生物多樣性的影響成為今日重要的課題之一。本研究針對六龜試驗林 扇乎地區之人工針葉林與人工闊葉林,分別就其所有木本植物、林下灌層、及地被植物層加 以分析討論,應用如豐富度指數、Simpson優勢度指數、Shannon多樣性指數、及Shannon 均勻度指數等生物多樣性指數,探討皆伐對人工林林下灌木層與地被植物層生物多樣性之影 響,並利用初步之鳥類調查資料,驗證鳥類多樣性於人工針葉林與人工闊葉林之差異,以了 解皆伐及其後之育林作業對長期生物多樣性變化與物種之出現所造成之影響。 生物多樣性之分析結果顯示落葉之人工闊葉林,不論在林下灌層或草本植物層,皆有較 高之生物多樣性。人工針葉林之林下灌層並無顯著之優勢種產生。光線的可及性、造林的成 敗與方式、造林地與周圍環境之空間變異情形、以及造林樹種與入侵樹種的生長速度等都可 能是造成這兩種造林地林下灌層與地被植物層生物多樣性不同的原因。 鳥類的豐度排序圖及生物多樣性分析亦顯示與植被相同的現象。落葉的人工闊葉林明顯 地有較多的鳥種出現,可能是因為人工闊葉林較多的林下灌木樹種與草本植物種,有較大的 機率符合某些鳥類特殊的食性與築巢需求。其詳細之分布差異及差異之驅動機制上有待深入 探討。
This study presents data from vegetation plots of managed deciduous hardwood and conifer plantations in the Upper Liukuei area of southern Taiwan to test the responses of understory and ground vegetation communities to clear cuts. A pooled quadrat method was used to determine sample size. Rank abundance plots and diversity indices such as species richness, Simpson index, Shannon index, and Shannon evenness index were used to elucidate differences in diversity of the plantations. Preliminary analysis of bird survey data was used to determine the effect of forest types on bird diversity. Diversity analysis suggested that for both understory and ground vegetation, deciduous hardwood plantations are higher in diversity. Differences in levels of available sunlight and rates of re-establishment/growth during plantation development may have driven these trends. Bird analysis also showed significantly higher diversity in deciduous hardwood plantations. Specific food or nesting requirements of bird species may be the cause.