Fire and fuel management is a high priority in North American sagebrush ecosystems where the expansion of piñon and juniper trees and the invasion of nonnative annual grasses are altering fire regimes and resulting in loss of sagebrush species and habitat. We evaluated 10‐yr effects of woody fuel treatments on sagebrush recruitment and plant functional group interactions using Sagebrush Steppe Treatment Evaluation Project data. We used mixed‐effects ANOVAs to examine treatment effects on sagebrush density and cover and perennial and annual grass cover in expansion woodlands (prescribed fire and cut‐and‐leave) and annual grass invasion areas (prescribed fire, mowing, tebuthiuron herbicide application). We used piecewise structural equation models to evaluate interactions among sagebrush seedling density, juvenile and adult density, and cover and perennial and annual grass cover. Fuel treatments were equated to pulse or press disturbances varying in resource release and subsequent intra‐ and interspecific interactions. Prescribed fire, a high magnitude pulse disturbance with more severe effects in warm and dry sites, reduced sagebrush cover and decoupled associations among sagebrush seedlings, juvenile and adult density, and cover indicating changed population structure. Cutting and leaving trees, a low magnitude pulse disturbance in cooler and moister woodlands, increased sagebrush density and cover and generally had lesser effects on sagebrush intraspecific associations. Mowing, a moderate magnitude pulse disturbance, and tebuthiuron herbicide application, a multiyear press disturbance, reduced sagebrush cover and disrupted intraspecific relationships. Competitive release increased cover of perennial grass in all treatments but tebuthiuron. Annual grass increased in all treatments, especially prescribed fire and tebuthiuron. Annual and perennial grass interactions with sagebrush were generally rare, but in woodland treatments perennial grass suppressed annual grass through year 6. Treatments in cooler and moister woodland sites had more positive effects on sagebrush recruitment and perennial grass cover, less negative effects on sagebrush intraspecific interactions, and smaller increases in annual grass cover indicating potential increases in resilience to fire. In warmer and drier invasion sites, reductions in woody fuels resulted in lack of sagebrush recruitment, disruption of sagebrush intraspecific interactions, and progressive increases in annual grass indicating reduced resilience to fire and resistance to invaders.

中文翻译：

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扰动类型和植物官能团相互作用介导的燃料处理后的鼠尾草恢复模式

在北美鼠尾草生态系统中，火和燃料管理是高度优先事项，那里松树和杜松的扩张以及非本地一年生草的入侵正在改变着火状况，并导致鼠尾草物种和栖息地的丧失。我们使用鼠尾草草原处理评估项目数据评估了木质燃料处理对鼠尾草招募和植物官能团相互作用的10年影响。我们使用了混合效应方差分析（ANOVA）来检查对扩张林地（规定的火和割留后的叶子）和年度草地入侵地区（规定的火，割草，丁苯妥隆除草剂的使用）的鼠尾草密度和覆盖率以及多年生和一年生草覆盖的处理效果。我们使用分段结构方程模型评估了鼠尾草幼苗密度，少年和成年密度之间的相互作用，以及多年生和一年生的草皮。燃料处理等同于脉冲或压力扰动，这些扰动随资源释放以及随后的种内和种间相互作用而变化。规定的火势，强烈的脉冲扰动在温暖和干燥的地方造成更严重的影响，鼠尾草的覆盖减少，并且鼠尾草幼苗，幼虫和成虫的密度之间的关联解耦，并且遮盖表明种群结构发生了变化。砍伐和离开树木，在较凉和潮湿的林地中产生较小的脉冲干扰，增加了鼠尾草的密度和覆盖度，并且通常对鼠尾草种内关联的影响较小。割草，中度脉冲干扰和替丁硫龙除草剂的应用，多年压榨干扰，鼠尾草覆盖率降低以及种内关系被破坏。竞争性释放增加了除替丁硫龙以外的所有处理中多年生草的覆盖率。在所有处理中，一年生禾草均增加，特别是开明的火和替丁硫龙。每年和多年生草与鼠尾草的相互作用通常很少见，但是在林地处理中，多年生草抑制了直到第6年的一年生草。在凉爽和潮湿的林地进行的处理对鼠尾草的招募和多年生草的覆盖产生更大的积极影响，对鼠尾草种内相互作用的负面影响较小。 ，并且每年草皮的增加幅度较小，这表明防火能力有可能增加。在温暖和干燥的入侵地点，木质燃料的减少导致鼠尾草的募集不足，鼠尾草种内相互作用的破坏，