Pearson Scott F, Knapp Shannon M
Washington Department of Fish and Wildlife, Wildlife Research Division, 1111 Washington St. SE., Olympia, Washington, 98501, United States of America.
Statistics Consulting Lab, Bio5 Institute, University of Arizona, 1657 E. Helen St., Tucson, Arizona, 85721, United States of America.
PLoS One. 2016 Jun 20;11(6):e0156330. doi: 10.1371/journal.pone.0156330. eCollection 2016.
Habitat selection that has fitness consequences has important implications for conservation activities. For example, habitat characteristics that influence nest success in birds can be manipulated to improve habitat quality with the goal of ultimately improving reproductive success. We examined habitat selection by the threatened streaked horned lark (Eremophila alpestris strigata) at both the breeding-site (territory) and nest-site scales. Larks were selective at both spatial scales but with contrasting selection. At the territory scale, male larks selected sparsely vegetated grasslands with relatively short vegetation. At the nest-site scale, female larks selected sites within territories with higher vegetation density and more perennial forbs. These nest-site scale choices had reproductive consequences, with greater nest success in areas with higher densities of perennial forbs. We experimentally manipulated lark habitat structure in an attempt to mimic the habitat conditions selected by larks by using late summer prescribed fires. After the burn, changes in vegetation structure were in the direction preferred by larks but habitat effects attenuated by the following year. Our results highlight the importance of evaluating habitat selection at spatial scales appropriate to the species of interest, especially when attempting to improve habitat quality for rare and declining species. They also highlight the importance of conducting restoration activities in a research context. For example, because the sparsely vegetated conditions created by fire attenuate, there may be value in examining more frequent burns or hotter fires as the next management and research action. We hope the design outlined in this study will serve as an integrated research and management example for conserving grassland birds generally.
具有适应性后果的栖息地选择对保护活动具有重要影响。例如，影响鸟类筑巢成功率的栖息地特征可以通过人为干预来改善栖息地质量，最终目标是提高繁殖成功率。我们在繁殖地（领地）和筑巢地尺度上研究了受威胁的细纹角百灵（Eremophila alpestris strigata）的栖息地选择。百灵在这两个空间尺度上都具有选择性，但选择方式不同。在领地尺度上，雄性百灵选择植被稀疏、相对低矮的草原。在筑巢地尺度上，雌性百灵在领地内选择植被密度较高且多年生草本植物较多的地点。这些筑巢地尺度的选择产生了繁殖后果，多年生草本植物密度较高的地区筑巢成功率更高。我们通过在夏末进行规定火烧实验性地改变了百灵的栖息地结构，试图模拟百灵选择的栖息地条件。火烧后，植被结构的变化朝着百灵偏好的方向发展，但栖息地效应到次年就减弱了。我们的研究结果凸显了在适合目标物种的空间尺度上评估栖息地选择的重要性，尤其是在试图改善珍稀和数量减少物种的栖息地质量时。它们还强调了在研究背景下开展恢复活动的重要性。例如，由于火烧造成的植被稀疏条件会减弱，作为下一步管理和研究行动，研究更频繁的火烧或更剧烈的火烧可能具有价值。我们希望本研究中概述的设计能够成为保护草原鸟类的综合研究与管理范例。
