Energy development and its associated infrastructure, including power lines, may influence wildlife population dynamics through effects on survival, reproduction, and movements of individuals. These infrastructure impacts may be direct or indirect, the former occurring when development acts directly as an agent of mortality (e.g., collision) and the latter when impacts occur as a by‐product of other processes that are altered by infrastructure presence. Functional or numerical responses by predators to power‐line corridors are indirect impacts that may suppress demographic rates for certain species, and perceived predation risk may affect animal behaviors such as habitat selection. Greater sage‐grouse (Centrocercus urophasianus) are a species of conservation concern across western North America that may be affected by power lines. Previous studies, however, have not provided evidence for causal mechanisms influencing demographic rates. Our primary objective was to assess the influence of power lines on multiple sage‐grouse vital rates, greater sage‐grouse habitat selection, and ultimately greater sage‐grouse population dynamics. We used demographic and behavioral data for greater sage‐grouse collected from 2003 to 2012 in central Nevada, USA, accounting for sources of underlying environmental heterogeneity. We also concurrently monitored populations of common ravens (Corvus corax), a primary predator of sage‐grouse nests and young. We focused primarily on a single 345 kV transmission line that was constructed at the beginning of our study; however, we also determined if similar patterns were associated with other nearby, preexisting power lines. We found that numerous behaviors (e.g., nest‐site selection, brood‐site selection) and demographic rates (e.g., nest survival, recruitment, and population growth) were affected by power lines, and that these negative effects were predominantly explained by temporal variation in the relative abundance of common ravens. Specifically, in years of high common raven abundance, avoidance of the transmission line was extended farther from the line, re‐nesting propensity was reduced, and nest survival was lower near the transmission line relative to areas more distant from the transmission line. Additionally, we found that before and immediately after construction of the transmission line, habitats near the footprint of the transmission line were generally more productive (e.g., greater reproductive success and population growth) than areas farther from the transmission line. However, multiple demographic rates (i.e., pre‐fledging chick survival, annual male survival, per capita recruitment, and population growth) for groups of individuals that used habitats near the transmission line declined to a greater extent than for individuals using habitats more distant in the years following construction of the transmission line. These decreases were correlated with an increase in common raven abundance. The geographical extent to which power lines negatively influence greater sage‐grouse demographic processes was thus contingent on local raven abundance and behavior. In this system, we found that effects of power lines, depending on the behavior or demographic rate, extended 2.5–12.5 km, which exceeds current recommendations for the placement of structures in areas around sage‐grouse leks. Nests located 12.5 km from the transmission line had 0.06 to 0.14 higher probabilities of hatching in years of average to high levels of raven abundance, relative to nests located within 1 km of the transmission line. Similarly, leks located 5 km from the transmission line had 0.02 to 0.16 higher rates of population growth (λ) in years of average to high levels of raven abundance, relative to leks located within 1 km of the transmission line. Our finding that negative impacts of the transmission line were associated with common raven abundance suggest that management actions that decouple this association between common raven abundance and power lines may reduce the negative indirect impacts of power lines on greater sage‐grouse population dynamics. However, because the removal of common ravens or the use of perch deterrents on power lines has not been demonstrated to be consistently effective in reducing common raven predation rates on greater sage‐grouse nests, we recommend preferential treatment to mitigation strategies that reduce the number of elevated structures placed within 10 km of critical greater sage‐grouse habitat. © 2018 The Wildlife Society.

中文翻译：

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电源线对鼠尾草（Centrocercus urophasianus）的栖息地使用和人口统计学的影响

能源开发及其相关基础设施（包括输电线）可能会通过影响个体的生存，繁殖和活动来影响野生动植物种群的动态。这些基础设施的影响可能是直接的或间接的，前者发生在发展直接充当死亡的媒介（例如冲突）时，后者发生在影响是其他过程的副产品（其基础设施存在而改变）的副产品中。捕食者对电力线走廊的功能或数字响应是间接影响，可能会抑制某些物种的人口统计率，并且感知到的捕食风险可能会影响动物的行为，例如栖息地选择。较高的鼠尾草（Centrocerercus urophasianus）是整个北美西部可能受到保护的物种，可能会受到电线的影响。但是，先前的研究尚未提供影响人口统计学因素的因果机制的证据。我们的主要目标是评估电源线对多种鼠尾草生命率，更大的鼠尾草栖息地选择以及最终更大的鼠尾草种群动态的影响。我们使用人口统计和行为数据，从2003年至2012年在美国内华达州中部收集了更多的鼠尾草，说明了潜在的环境异质性来源。我们还同时监视了常见的乌鸦（乌鸦座corax），鼠尾草巢和幼鸟的主要捕食者。在研究开始时，我们主要关注的是一条345 kV输电线路。但是，我们还确定了类似的模式是否与附近的其他先前存在的电源线相关联。我们发现电力线影响了许多行为（例如，巢位选择，育雏位选择）和人口统计率（例如巢生存，募集和种群增长），并且这些负面影响主要是由时间变化解释的。在相对丰富的普通乌鸦中。具体而言，在常见乌鸦丰度很高的年份，对传输线的避开距离该线越远，重新嵌套的倾向就越小，相对于远离传输线的区域，传输线附近的巢生存率较低。另外，我们发现，在输电线路建设之前和之后，与远离输电线路的地区相比，靠近输电线路足迹的栖息地通常生产力更高（例如，更大的繁殖成功率和人口增长）。但是，多种人口统计率（例如，雏鸡成活前，雄性每年成活，人均在传输线建成后的几年中，使用传输线附近生境的个人群体的下降幅度更大，而使用传输线附近生境的个人群体的下降幅度更大。这些减少与普通乌鸦丰度增加有关。因此，电力线在地理上对更大的鼠尾草人口统计过程产生负面影响的程度取决于当地的乌鸦数量和行为。在该系统中，我们发现，根据行为或人口统计学的影响，电力线的影响范围扩大了2.5–12.5 km，超出了当前在鼠尾草韭菜周围地区放置结构的建议。距离传输线12.5公里的巢数为0.06到0。与距离传输线1公里以内的巢相比，在平均水平到高乌鸦丰度水平下，每年有14个更高的孵化率。同样，相对于距离传输线1 km以内的韭菜，距离传输线5 km的韭菜在多年平均至高乌鸦丰度水平下的人口增长率（λ）高0.02至0.16。我们的发现，输电线路的负面影响与普通乌鸦的丰度相关联，这表明，将普通乌鸦丰度和电力线之间的这种联系解耦的管理措施可以减少电力线对更大的鼠尾草种群动态的负面间接影响。然而，由于尚未证明去除常见的乌鸦或在电力线上使用鲈鱼威慑作用一直能有效地减少较大的鼠尾草巢上常见的乌鸦被捕食率，因此，我们建议对减少减少高架结构数量的缓解策略给予优惠待遇放置在重要​​的鼠尾草栖息地10公里以内。©2018野生动物协会。