Abstract Wildland fire is a disturbance that shapes frequent-fire forest ecosystems and the life-histories of wildlife species that inhabit them. The California spotted owl (Strix occidentalis occidentalis) is an iconic old-forest species that evolved under a frequent-fire regime in western North America. While recent studies have focused on owl response to large, severe fire events, relatively little is known about how owls might respond to prescribed fires and wildfires managed for resource benefit. Therefore, understanding how owls use landscapes that are managed using fire may offer insight into how owls respond to fire management. We studied the breeding season nocturnal foraging habitat selection of 22 GPS-tagged California spotted owls in three national parks (Yosemite, Sequoia, and Kings Canyon) in the Sierra Nevada, California, USA where natural fires have largely been allowed to burn during the past 50 years and controlled burning has been used to target additional areas. Consistent with other studies of this species, owls selected forests dominated by medium and large trees and avoided areas with smaller trees within their home ranges based on step selection analysis. Owls neither selected nor avoided forests burned by low- and moderate-severity, or high-severity fires, yet avoided larger patches of severely-burned forest (odds of selection decreased by 20% for every 10 ha increase in severely-burned patch area). These results indicated the importance of patch characteristics, suggesting that larger patches reflected either lower quality foraging habitat or increased predation risk, even in these frequent-fire landscapes where “large” severely-burned patches were small compared to those common after megafires. Additionally, selection strength increased for areas burned recently by lower-severity fire and, to a lesser extent, by older fires (largely of lower severity) as the extent of these burned areas increased within individual home ranges. These results suggested that lower-severity fire benefitted spotted owls and that these benefits declined over time. Thus, our findings are consistent with the hypothesis that California spotted owls are adapted to historical frequent-fire regimes of overall lower-severity with small high-severity patches. We hypothesize that fire management, coupled with medium- and large-tree retention, likely maintains high quality spotted owl habitat and may contribute to the observed owl population stability in Sequoia and Kings Canyon National Parks, compared to declining populations on three national forests. Finally, our results indicated that fire management, as practiced in these national parks, could benefit owl conservation elsewhere if challenges to the reintroduction of frequent-fire regimes can be overcome.

中文翻译：

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加利福尼亚在火灾管理景观中发现猫头鹰栖息地选择表明恢复历史火灾制度的保护益处

摘要 野火是一种干扰，它塑造了频繁发生火灾的森林生态系统和栖息在其中的野生动物物种的生活史。加利福尼亚斑鸮（Strix occidentalis occidentalis）是一种标志性的古老森林物种，在北美西部频繁发生火灾的情况下进化而来。虽然最近的研究集中在猫头鹰对大型严重火灾事件的反应上，但对于猫头鹰如何应对规定的火灾和为资源利益进行管理的野火，人们知之甚少。因此，了解猫头鹰如何使用使用火管理的景观可能有助于深入了解猫头鹰如何应对火灾管理。我们研究了加利福尼亚内华达山脉三个国家公园（优胜美地、红杉和国王峡谷）中 22 只 GPS 标记的加利福尼亚斑点猫头鹰的繁殖季节夜间觅食栖息地选择，美国在过去的 50 年中在很大程度上允许自然火燃烧，并且已使用受控燃烧来瞄准其他区域。与该物种的其他研究一致，猫头鹰选择以中型和大型树木为主的森林，并根据步骤选择分析避开其栖息地内有较小树木的区域。猫头鹰既没有选择也没有避开被低度和中度或高度火灾烧毁的森林，但避开了大片的严重燃烧的森林（严重燃烧的面积每增加 10 公顷，选择的几率就会降低 20%） . 这些结果表明斑块特征的重要性，表明较大的斑块反映了较低质量的觅食栖息地或增加的捕食风险，即使在这些频繁发生火灾的景观中，“大”严重燃烧的斑块与大火之后的常见斑块相比也很小。此外，随着这些燃烧区域在各个家庭范围内的范围增加，最近被较低严重性火灾和较旧的火灾（主要是较低严重性）烧毁的区域的选择强度增加了。这些结果表明，较低严重程度的火灾使斑点猫头鹰受益，但这些好处随着时间的推移而下降。因此，我们的研究结果与加利福尼亚斑点猫头鹰适应历史上总体较低严重性和小的高严重性斑块的频繁火灾制度的假设一致。我们假设火灾管理加上中型和大型树木的保留，与三个国家森林的种群数量下降相比，可能维持高质量的斑点猫头鹰栖息地，并可能有助于观察到红杉和国王峡谷国家公园猫头鹰种群的稳定性。最后，我们的研究结果表明，如果可以克服重新引入频繁火灾制度的挑战，那么在这些国家公园实施的火灾管理可能有利于其他地方的猫头鹰保护。