Department of Environmental Science Policy and Management, University of California, Berkeley, California 94720-3114, USA.
Ecol Appl. 2011 Mar;21(2):565-76. doi: 10.1890/10-0496.1.
The presence of intact natural ecosystems in agricultural landscapes can mitigate losses in the diversity of natural enemies and enhance ecosystem services. However, native natural enemies may fail to persist in agroecosystems if invaders dominate species interactions. In this study, native and nonnative spiders were sampled along transects that extended from oak woodland and riparian zones into surrounding California vineyards, to assess the role of natural habitat as a source for spider biodiversity in the vineyard landscape, and to compare the dominance of exotic Cheiracanthium spiders between habitats. Many spider species were more abundant in natural habitat than in vineyards, and numbers of spiders and spider species within vineyards were higher at the vineyard edge adjacent to oak woodland. These results suggest that natural habitat is a key source for spiders in vineyards. The positive effect of oak woodland on the vineyard spider community extended only to the vineyard edge, however. Proportions of Cheiracanthium spiders increased dramatically in the vineyard, while numbers of native wandering spiders (the native ecological homologues of Cheiracanthium spiders) decreased. Dispersal limitation and strong habitat preferences may have prevented native wandering spiders from establishing far from the vineyard edge. Exotic Cheiracanthium spiders, in contrast, may possess specific adaptations to vineyards or to a wide range of habitats. Results suggest that the ecosystem services provided by intact natural habitat may be limited in agricultural landscapes that are dominated by invasive species.
农业景观中完整的自然生态系统的存在可以减轻天敌多样性的丧失，并增强生态系统服务。然而，如果入侵物种主导了物种间的相互作用，本地天敌可能无法在农业生态系统中持续存在。在这项研究中，沿着从橡树林和河岸带延伸到周围加利福尼亚葡萄园的样带，对本地和非本地蜘蛛进行了采样，以评估自然栖息地作为葡萄园景观中蜘蛛生物多样性的来源的作用，并比较栖息地之间外来 Cheiracanthium 蜘蛛的优势度。许多蜘蛛物种在自然栖息地比在葡萄园更丰富，而在葡萄园边缘靠近橡树林的地方，蜘蛛和蜘蛛物种的数量更高。这些结果表明，自然栖息地是葡萄园蜘蛛的关键来源。然而，橡树林对葡萄园蜘蛛群落的积极影响仅延伸到葡萄园边缘。Cheiracanthium 蜘蛛的比例在葡萄园急剧增加，而本地游走蛛（Cheiracanthium 蜘蛛的本地生态同系物）的数量减少。扩散限制和强烈的栖息地偏好可能阻止了本地游走蛛远离葡萄园边缘建立种群。相比之下，外来 Cheiracanthium 蜘蛛可能具有特定的适应能力，可以适应葡萄园或广泛的栖息地。结果表明，在以入侵物种为主导的农业景观中，完整自然栖息地提供的生态系统服务可能受到限制。
