Drastic increases in wildfire size and frequency threaten western North American sagebrush (Artemisia L. spp.) ecosystems. At relatively large spatial scales, wildfire facilitates type conversion of sagebrush-dominated plant communities to monocultures of invasive annual grasses (e.g., Bromus tectorum L.). Annual grasses provide fine fuels that promote fire spread, contributing to a positive grass–fire feedback cycle that affects most sagebrush ecosystems, with expected habitat loss for resident wildlife populations. Greater sage-grouse (Centrocercus urophasianus Bonaparte, 1827) are sagebrush obligate species that are indicators of sagebrush ecosystem function because they rely on different components of sagebrush ecosystems to meet seasonal life history needs. Because wildfire cannot be predicted, chronic impacts of wildfire on sage-grouse populations have been largely limited to correlative studies. Thus, evidence from well-designed experiments is needed to understand the specific mechanisms by which wildfire is detrimental to sage-grouse population dynamics. Following a significant wildfire event in the southwest periphery of sage-grouse range, we implemented a before-after-control-impact study with long-term paired (BACIP) datasets of male sage-grouse surveyed from traditional breeding grounds (leks) within and outside the wildfire boundary. We estimated sage-grouse population rate of change in apparent abundance ( $$ \hat{\uplambda} $$ ) at burned and unburned areas before and after wildfire and derived BACIP ratios, which provide controlled evidence of wildfire impact. We found that $$ \hat{\uplambda} $$ at leks within the wildfire boundary decreased approximately 16% relative to leks at control sites. Furthermore, we estimated a 98.5% probability that the observed change in $$ \hat{\uplambda} $$ could be attributed to the wildfire. We demonstrated adverse wildfire impacts on sage-grouse population growth using an experimental BACIP design, which disentangled the effect of wildfire disturbance from natural population fluctuations. Our results underscore the importance of active and comprehensive management actions immediately following wildfire (i.e., seeding coupled with planting sagebrush), that might offset short-term impacts of wildfire by timing rapid recovery of sagebrush to meet short-term species’ habitat requirements. Burned leks likely have substantial immediate impacts that may extend beyond wildfire boundaries, especially if critical source habitats are removed. Such impacts could fragment habitat and disrupt connectivity, thereby affecting larger populations and possibly contributing to more widespread declines in sage-grouse populations.

中文翻译：

---

大规模野火减少了鼠尾草外围人群的人口增长

野火的大小和频率急剧增加，威胁到北美西部的鼠尾草（Artemisia L. spp。）生态系统。在相对较大的空间尺度上，野火有助于将以鼠尾草为主的植物群落类型转化为入侵性一年生禾本科植物（例如Bromus tectorum L.）的单一栽培。一年生的草提供了促进火势蔓延的优良燃料，促进了积极的草火反馈循环，影响了大多数鼠尾草的生态系统，并给当地野生动植物种群带来了预期的栖息地损失。较高的鼠尾草（Centrocercus urophasianus Bonaparte，1827年）是鼠尾草专性物种，它们是鼠尾草生态系统功能的指标，因为它们依赖于鼠尾草生态系统的不同组成部分来满足季节性生活史的需求。由于无法预测野火，野火对鼠尾草种群的长期影响在很大程度上仅限于相关研究。因此，需要有精心设计的实验的证据来了解野火有害于鼠尾草种群动态的具体机制。在鼠尾草范围西南边缘发生重大野火事件之后，我们实施了“控制后影响”研究，该研究使用了雄性鼠尾草的长期配对（BACIP）数据集，该数据集是从鼠尾草的传统繁殖场（韭菜）中调查的。在野火边界之外。我们估算了野火前后火烧区和未烧区鼠尾草种群的表观丰度变化率，并得出了BACIP比率，这提供了野火影响的可控证据。我们发现，野火边界内韭菜的$$ \ hat {\ uplambda} $$相对于控制地点的韭菜减少了约16％。此外，我们估计观察到的$$ \ hat {$ uplambda} $$变化可归因于野火的概率为98.5％。我们使用实验性BACIP设计展示了野火对鼠尾草种群增长的不利影响，该设计将野火干扰的影响与自然种群波动区分开来。我们的结果强调了在野火之后（即播种与种植鼠尾草）立即采取积极而全面的管理措施的重要性，这可以通过安排迅速恢复鼠尾草以满足短期物种的栖息地需求来抵消野火的短期影响。焚烧的韭菜可能立即产生重大影响，可能会超出野火范围，尤其是如果关键的源头栖息地被清除的话。这种影响可能会破坏栖息地并破坏连通性，从而影响更多的人口，并可能导致鼠尾草种群的下降。