The diversity and abundance of North American bird assemblages fail to track changing productivity.
The diversity and abundance of North American bird assemblages fail to track changing productivity.
复制标题
北美鸟类群落的多样性和丰富性未能追踪生产力的变化。
作者：
L. Dobson;F. L. La Sorte;L. Manne;B. Hawkins
植物生物量或生产力与鸟类物种丰富度在一系列空间尺度上存在关联。物种能量理论通常被认为可以解释这些相关性。如果这是正确的，那么鸟类丰富度也应该在时间上跟踪生产力，并且生产力与鸟类丰富度和鸟类丰富度之间应该存在时空关系。利用1982-2006年夏季归一化植被指数（NDVI）和北美种鸟调查资料，分析了鸟类丰富度和丰度对植物生物量或生产力年际变化的响应。丰富度与NDVI在25年内均呈正相关。在时间上，丰富度与NDVI在1579个调查点呈正相关，在1627个调查点呈负相关（平均r2 = 0.09）。此外，总丰度与NDVI在空间上不相关（r2值跨越< 0.01和0.03），在时间上呈弱相关（平均r2 = 0.10）。我们没有发现生产力驱动鸟类丰富度超越空间相关性的证据，物种能量理论的预测也没有得到证实。因此，生产力和鸟类丰富度之间的空间关系可能在很大程度上是虚假的，这是通过植物生物量或生产力与植被结构复杂性之间的协方差产生的，后者可能驱动鸟类群落。这与麦克阿瑟的经典假设一致，即树叶的垂直轮廓驱动鸟类物种多样性。
Plant biomass or productivity and the species richness of birds are associated across a range of spatial scales. Species-energy theory is generally assumed to explain these correlations. If true, bird richness should also track productivity temporally, and there should be spatial and temporal relationships between productivity and both bird abundance and bird richness. Using the summer normalized difference vegetation index (NDVI) for 1982-2006 and the North American Breeding Bird Survey, we evaluated the response of avian richness and abundance to interannual changes in plant biomass or productivity. We found positive spatial relationships between richness and NDVI for all 25 years. Temporally, however, richness and NDVI were positively associated at 1579 survey sites and negatively associated at 1627 sites (mean r2 = 0.09). Further, total abundance and NDVI were unrelated spatially (r2 values spanning < 0.01 and 0.03) and weakly related temporally (mean r2 = 0.10). We found no evidence that productivity drives bird richness beyond the spatial correlations, and neither prediction arising from species-energy theory was confirmed. Spatial relationships between productivity and bird richness may thus be largely spurious, arising via covariance between plant biomass or productivity and vegetation structural complexity, and the latter may be driving bird communities. This is consistent with the MacArthurs' classic hypothesis that the vertical profile of foliage drives bird species diversity.
影响因子：
3.9
作者：
Brown JH
通讯作者：
Brown JH