Anand Mandyam Osuri, Krishnaswamy Jagdish, Das Arundhati
Post-graduate Program in Wildlife Biology and Conservation, Wildlife Conservation Society-India, National Centre for Biological Sciences, P.O. Box 6501, Hebbal, Bangalore, India.
Ecol Appl. 2008 Oct;18(7):1754-63. doi: 10.1890/07-1545.1.
Widespread loss of primary habitat in the tropics has led to increased interest in production landscapes for biodiversity conservation. In the Western Ghats biodiversity hotspot in India, shade coffee plantations are located in close proximity to sites of high conservation value: protected and unprotected forests. Coffee is grown here under a tree canopy that may be dominated by native tree species or by nonnative species, particularly silver oak (Grevillea robusta). We investigated the influence of properties at the local scale and the landscape scale in determining bird communities in coffee plantations, with particular emphasis on species of conservation priority. We used systematic point counts in 11 coffee plantation sites and analyzed data in a randomized linear modeling framework that addressed spatial autocorrelation. Greater proportion of silver oak at the local scale and distance to contiguous forests at the landscape scale were implicated as factors most strongly driving declines in bird species richness and abundance, while increased basal area of native tree species, a local-scale variable, was frequently related to increased bird species richness and abundance. The influence of local-scale variables increased at greater distances from the forest. Distance to forests emerged as the strongest predictor of declines in restricted-range species, with 92% reduction in the abundance of two commonly encountered restricted-range species (Pompadour Green Pigeon and Yellow-browed Bulbul) and a 43% reduction in richness of bird species restricted to Indian hill forests within 8 km of forests. Increase in proportion of silver oak from 33% to 55% was associated with 91% reduction in the abundance of one commonly encountered restricted-range species (Crimson-fronted Barbet). One conservation strategy is providing incentives to grow coffee in a biodiversity-friendly manner. One implication of our study is that plantations located at varying distances to the forest cannot be compared fairly for biodiversity friendliness by existing certification methodology. Another is that conservation of existing forests at the landscape scale is essential for maintaining higher biodiversity in coffee plantations. Incentive schemes that promote conservation of remnant forests at the landscape scale and biodiversity-friendly practices locally and that relate to coffee communities as a whole rather than individual planters are likely to be more effective.
热带地区原生栖息地的广泛丧失，使得人们对用于生物多样性保护的生产性景观的兴趣日益浓厚。在印度的西高止山脉生物多样性热点地区，遮荫咖啡种植园紧邻具有高保护价值的区域：受保护和未受保护的森林。这里种植咖啡的树冠层可能以本地树种为主，也可能以非本地树种为主，特别是银橡树（绢毛相思树）。我们研究了局部尺度和景观尺度的属性对咖啡种植园中鸟类群落的影响，特别关注具有保护优先级的物种。我们在11个咖啡种植园地点进行了系统的点计数，并在一个解决空间自相关问题的随机线性建模框架中分析数据。局部尺度上银橡树的比例越高以及景观尺度上与相邻森林的距离越远，被认为是导致鸟类物种丰富度和数量下降的最主要因素，而本地树种基部面积的增加（一个局部尺度变量）则常常与鸟类物种丰富度和数量的增加相关。局部尺度变量的影响在离森林较远的地方会增强。到森林的距离成为限制分布物种数量下降的最强预测因子，在距离森林8公里范围内，两种常见的限制分布物种（果绿鸠和黄眉鹎）的数量减少了92%，局限于印度山地森林的鸟类物种丰富度减少了43%。银橡树比例从33%增加到55%，与一种常见的限制分布物种（红头拟啄木鸟）数量减少91%相关。一种保护策略是提供激励措施，促使以有利于生物多样性的方式种植咖啡。我们研究的一个启示是，现有认证方法无法公平地比较距离森林远近不同的种植园对生物多样性的友好程度。另一个启示是，在景观尺度上保护现有森林对于维持咖啡种植园中更高的生物多样性至关重要。促进景观尺度上残余森林保护以及局部有利于生物多样性的做法且涉及整个咖啡种植社区而非个别种植者的激励计划可能会更有效。
