U.S. Geological Survey, Western Ecological Research Center, Dixon Field Station, 800 Business Park Drive, Suite D, Dixon, California, 95620, USA.
USDA Forest Service, Rocky Mountain Research Station, 920 Valley Road, Reno, Nevada, 89512, USA.
Ecol Appl. 2018 Jun;28(4):878-896. doi: 10.1002/eap.1690. Epub 2018 May 21.
Managers require quantitative yet tractable tools that identify areas for restoration yielding effective benefits for targeted wildlife species and the ecosystems they inhabit. As a contemporary example of high national significance for conservation, the persistence of Greater Sage-grouse (Centrocercus urophasianus) in the Great Basin is compromised by strongly interacting stressors of conifer expansion, annual grass invasion, and more frequent wildfires occurring in sagebrush ecosystems. Associated restoration treatments to a sagebrush-dominated state are often costly and may yield relatively little ecological benefit to sage-grouse if implemented without estimating how Sage-grouse may respond to treatments, or do not consider underlying processes influencing sagebrush ecosystem resilience to disturbance and resistance to invasive species. Here, we describe example applications of a spatially explicit conservation planning tool (CPT) to inform prioritization of: (1) removal of conifers (i.e., pinyon-juniper); and (2) wildfire restoration aimed at improving habitat conditions for the Bi-State Distinct Population Segment of Sage-grouse along the California-Nevada state line. The CPT measures ecological benefits to sage-grouse for a given management action through a composite index comprised of resource selection functions and estimates of abundance and space use. For pinyon-juniper removal, we simulated changes in land-cover composition following the removal of sparse trees with intact understories, and ranked treatments on the basis of changes in ecological benefits per dollar-unit of cost. For wildfire restoration, we formulated a conditional model to simulate scenarios for land cover changes (e.g., sagebrush to annual grass) given estimated fire severity and underlying ecosystem processes influencing resilience to disturbance and resistance to invasion by annual grasses. For both applications, we compared CPT rankings to land cover changes along with sagebrush resistance and resilience metrics. Model results demonstrated how the CPT can be an important step in identifying management projects that yield the highest quantifiable benefit to Sage-grouse while avoiding costly misallocation of resources, and highlight the importance of considering changes in sage-grouse ecological response and factors influencing sagebrush ecosystem resilience to disturbance and resistance to invasion. This unique framework can be adopted to help inform other management questions aimed at improving habitat for other species across sagebrush and other ecosystems.
管理者需要定量但易于处理的工具，这些工具能够确定需要恢复的区域，从而为目标野生物种及其栖息的生态系统带来有效的效益。大盆地的大角羊（Centrocercus urophasianus）的持续存在是一个具有当代重要意义的保护范例，它受到针叶树扩张、一年生草本植物入侵以及在山艾灌丛生态系统中更频繁发生野火等强烈相互作用的胁迫因素的影响。如果在没有估计大角羊对处理措施的反应的情况下实施与山艾灌丛占主导地位的状态相关的恢复措施，或者不考虑影响山艾灌丛对干扰的恢复力和对入侵物种的抵抗力的潜在过程，这些措施可能会给大角羊带来相对较小的生态效益，而且往往成本高昂。在这里，我们描述了一种空间显式保护规划工具（CPT）的应用实例，用于为以下方面提供信息：（1）去除针叶树（即松杉）；（2）野火恢复，目的是改善加利福尼亚州和内华达州州界沿线大角羊的双州特有种群的栖息地条件。CPT 通过由资源选择函数和丰度和空间利用估计组成的综合指数，为给定管理行动衡量对大角羊的生态效益。对于去除松杉，我们模拟了在去除具有完整下层植被的稀疏树木后土地覆盖组成的变化，并根据每美元成本的生态效益变化对处理措施进行了排名。对于野火恢复，我们制定了一个条件模型，根据估计的火灾严重程度和影响干扰恢复力和抵御一年生草本植物入侵的生态系统过程，模拟土地覆盖变化的情景（例如，山艾灌丛变为一年生草本植物）。对于这两种应用，我们将 CPT 排名与土地覆盖变化以及山艾灌丛抗性和恢复力指标进行了比较。模型结果表明，CPT 如何成为确定对大角羊产生最高可量化效益的管理项目的重要步骤，同时避免资源的错误分配，并强调考虑大角羊生态反应变化以及影响山艾灌丛干扰恢复力和抵御入侵的因素的重要性。这个独特的框架可以被采用来帮助解决其他旨在改善山艾灌丛和其他生态系统中其他物种栖息地的管理问题。
