ABSTRACT The vertical structure and composition of vegetation can influence the quantity and quality of potential nesting sites for birds. Interspecific competition for high-quality nesting habitat may force some individuals into suboptimal habitat and lead to reduced reproductive success, eventually leading to changes in distribution or abundance. Large climate-mediated shifts in vegetation, including the rapid expansion of shrubs onto tundra, are occurring in the Arctic across important breeding grounds of many shorebird species of conservation concern. We investigated effects of vegetation structure and composition on nest-site selection and nest success of sympatrically breeding American Golden-Plovers (Pluvialis dominica) and Pacific Golden-Plovers (P. fulva), which nest along an elevational gradient ranging from coastal tundra meadows to alpine tundra. Both species strongly selected nest sites with less cover of tall shrubs and other tall vegetation than available at random sites within their territories. American Golden-Plovers selected territories and nest sites that were higher in elevation and had more rocky substrates and less graminoid vegetation than those selected by Pacific Golden-Plovers. The daily nest survival rate was equivalent in the 2 species (0.966, 95% CI: 0.955, 0.975) and similar to that found in other Arctic-breeding shorebirds; however, contrary to predictions, nest survival was not associated with habitat features selected for nest sites for either species. Strong selection of open habitat for nest sites suggests that continued climate-related shrub expansion may reduce the amount of suitable breeding habitat for both species, but partitioning along the elevational gradient and differences in body size suggest that impacts may be more severe for Pacific Golden-Plovers. Additional research is needed to determine if differential selection of nesting habitat is related to survival of the adults or their young.

中文翻译：

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同域鸻的栖息地划分会影响巢的生存吗？

摘要 植被的垂直结构和组成会影响鸟类潜在筑巢地的数量和质量。种间对优质筑巢栖息地的竞争可能会迫使一些个体进入次优栖息地并导致繁殖成功率降低，最终导致分布或丰度发生变化。气候介导的植被的大规模变化，包括灌木迅速扩展到苔原，正在北极地区发生，跨越许多受保护的滨鸟物种的重要繁殖地。我们研究了植被结构和组成对同域繁殖美国金鸻（Pluvialis dominica）和太平洋金鸻（P. fulva）的筑巢地点选择和筑巢成功的影响，它们沿着海拔梯度筑巢，从沿海苔原草甸到高山苔原。这两个物种都强烈选择了高灌木和其他高大植被覆盖率低于其领土内随机地点的筑巢地点。美国金鸻选择的领土和巢穴地点比太平洋金鸻选择的那些海拔更高、岩石基质更多、禾本科植物更少。2个物种的日巢存活率相当（0.966, 95% CI: 0.955, 0.975），与其他北极繁殖的滨鸟相似；然而，与预测相反，巢的存活与为任一物种的巢址选择的栖息地特征无关。为筑巢地点选择开阔的栖息地表明，持续的与气候相关的灌木扩张可能会减少这两种物种的适宜繁殖栖息地的数量，但沿海拔梯度的分区和体型大小的差异表明，太平洋金黄色的影响可能更严重。鸻。需要进一步研究以确定筑巢栖息地的差异选择是否与成虫或其幼崽的生存有关。