Richardson M L, Hanks L M
Program in Ecology, Evolution, and Conservation Biology, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA.
Environ Entomol. 2009 Dec;38(6):1595-9. doi: 10.1603/022.038.0610.
Native grasslands are among the most imperiled of the North American ecosystems, but abandoned agricultural areas may provide suitable habitat for animal taxa that are endemic to grasslands. We studied how species diversity of orb-weaving spiders was influenced by secondary succession of a grassland plant community by monitoring the abundance and species diversity in study plots that were cultivated at 6-yr intervals and left uncultivated in the interim. We tested the hypothesis that local abundance and species diversity of spiders would be positively associated with time since cultivation because plant communities in older habitats would be more architecturally complex. Local abundance of spiders in general was not associated with time since cultivation, but abundance of Mangora gibberosa (Hentz) was positively associated with the abundance of perennial plants. Species richness and diversity of spiders also were positively associated with the abundance of perennial plants and reached a threshold a few years after cultivation. Species diversity of orb-weaving spiders seems to be strongly influenced by species composition of the plant community. Therefore, effective restoration of the structure and function of endemic communities of orb-weaving spiders may depend on preserving endemic grassland plant communities.
原生草原是北美生态系统中受威胁最严重的生态系统之一，但废弃的农业区可能为草原特有的动物类群提供适宜的栖息地。我们通过监测每隔6年开垦一次并在其间休耕的样地中的丰度和物种多样性，研究了草原植物群落的次生演替如何影响圆蛛的物种多样性。我们检验了这样一个假设，即蜘蛛的局部丰度和物种多样性会与开垦后的时间呈正相关，因为较老栖息地中的植物群落结构会更复杂。总体而言，蜘蛛的局部丰度与开垦后的时间并无关联，但白纹眶蛛（Mangora gibberosa，亨茨）的丰度与多年生植物的丰度呈正相关。蜘蛛的物种丰富度和多样性也与多年生植物的丰度呈正相关，并在开垦后的几年达到一个阈值。圆蛛的物种多样性似乎受植物群落物种组成的强烈影响。因此，有效恢复圆蛛特有群落的结构和功能可能取决于保护特有的草原植物群落。
