Abstract:
Describing the spatial distribution of communities is crucial to understanding how environmental disturbance can affect biodiversity. Agricultural lands are susceptible to disturbances of anthropogenic origin and have been identified as ecosystems of conservation concern. Such lands are vulnerable to invasions by anthropogenically introduced non-native plants disturbing habitats. This research focused on the invasion-induced taxonomic filtering of birds with shared habitat requirements. The birds were surveyed along a gradient of invasion-altered areas (far from the invasion, uninvaded although susceptible to invaders, and invaded) to identify changes in bird assemblages (ground/herb dwellers, bush foragers, ecotone birds, and tree foragers) caused by this disturbance. Data were collected from 112 sites sampled in southeastern Poland. There were significantly fewer bird species from each assemblage on invaded sites than on uninvaded sites, although exposed to invasion, despite the decrease in the abundance of only ground/herb dwellers. Beta diversity analysis showed that sites with invasion contained bird communities significantly different from those at other sites. Invasion-induced changes resulted in a significant reduction in the diversity of ground/herb dwellers in comparison with uninvaded sites and created a distinctive bush bird assemblage. This was most likely due to the transformation of the grassland layer and the thickening of the shrub layer by plant invaders, which resemble shrubs in morphology. The results indicated the filtering effect of invasion on bird species composition at the level of two habitat assemblages despite the decreases in bird abundance and species diversity of the whole community.
摘要:
描述社区的空间分布对于理解环境干扰如何影响生物多样性至关重要。农业用地容易受到人为来源的干扰,已被确定为受保护的生态系统。这些土地很容易受到人为引入的非本地植物的入侵,这些植物扰乱了栖息地。这项研究的重点是入侵引起的具有共同栖息地要求的鸟类的分类过滤。沿着入侵改变的区域的梯度对鸟类进行了调查(远离入侵,虽然容易受到入侵者的侵袭,和入侵)以识别鸟类组合的变化(地面/草本植物居民,布什觅食者,过渡带鸟,和树木觅食者)由这种干扰引起。数据来自波兰东南部的112个地点。入侵地点的每个组合中的鸟类物种明显少于未入侵地点,虽然暴露于入侵,尽管只有地面/草药居民的数量减少。Beta多样性分析表明,入侵地点的鸟类群落与其他地点的鸟类群落显着不同。与未入侵的地点相比,入侵引起的变化导致地面/草本植物居民的多样性显着减少,并创造了独特的灌木鸟组合。这很可能是由于植物入侵者对草地层的改造和灌木层的增厚,形态类似灌木。结果表明,尽管整个群落的鸟类丰度和物种多样性下降,但入侵在两个栖息地组合水平上对鸟类物种组成的过滤作用。