Green David S, Martin Marie E, Matthews Sean M, Akins Jocelyn R, Carlson Jennifer, Figura Pete, Hatfield Brian E, Perrine John D, Quinn Cate B, Sacks Benjamin N, Stephenson Thomas R, Stock Sarah L, Tucker Jody M
Institute for Natural Resources, Oregon State University, Corvallis, Oregon 97331, USA.
Cascades Carnivore Project, 505 17th Street, Hood River, Oregon 97031, USA.
J Mammal. 2023 May 15;104(4):820-832. doi: 10.1093/jmammal/gyad026. eCollection 2023 Aug 1.
Carnivores play critical roles in ecosystems, yet many species are declining worldwide. The Sierra Nevada Red Fox (; SNRF) is a rare and endangered subspecies of red fox limited to upper montane forests, subalpine, and alpine environments of California and Oregon, United States. Having experienced significant distribution contractions and population declines in the last century, the subspecies is listed as at-risk by relevant federal and state agencies. Updated information on its contemporary distribution and density is needed to guide and evaluate conservation and management actions. We combined 12 years (2009-2020) of detection and nondetection data collected throughout California and Oregon to model the potential distribution and density of SNRFs throughout their historical and contemporary ranges. We used an integrated species distribution and density modeling approach, which predicted SNRF density in sampled locations based on observed relationships between environmental covariates and detection frequencies, and then projected those predictions to unsampled locations based on the estimated correlations with environmental covariates. This approach provided predictions that serve as density estimates in sampled regions and projections in unsampled areas. Our model predicted a density of 1.06 (95% credible interval = 0.8-1.36) foxes per 100 km distributed throughout 22,926 km in three distinct regions of California and Oregon-Sierra Nevada, Lassen Peak, and Oregon Cascades. SNRFs were most likely to be found in areas with low minimum temperatures and high snow water equivalent. Our results provide a contemporary baseline to inform the development and evaluation of conservation and management actions, and guide future survey efforts.
食肉动物在生态系统中发挥着关键作用，但全球许多物种数量都在下降。内华达山脉红狐（SNRF）是红狐的一种珍稀濒危亚种，仅分布于美国加利福尼亚州和俄勒冈州的高山森林、亚高山和高山环境中。在上个世纪经历了显著的分布收缩和种群数量下降后，该亚种被相关联邦和州机构列为濒危物种。需要更新的当代分布和密度信息来指导和评估保护与管理行动。我们整合了在加利福尼亚州和俄勒冈州收集的12年（2009 - 2020年）检测和未检测数据，以模拟内华达山脉红狐在其历史和当代分布范围内的潜在分布和密度。我们采用了一种综合的物种分布和密度建模方法，该方法基于环境协变量与检测频率之间的观测关系预测采样地点的内华达山脉红狐密度，然后根据与环境协变量的估计相关性将这些预测结果投影到未采样地点。这种方法提供的预测结果可作为采样区域的密度估计和未采样区域的预测。我们的模型预测，在加利福尼亚州和俄勒冈州的三个不同区域——内华达山脉、拉森峰和俄勒冈喀斯喀特山脉，每100平方公里有1.06只（95%可信区间 = 0.8 - 1.36）狐狸，分布在22926平方公里的区域内。在内华达山脉红狐最有可能被发现的地区，最低温度较低且雪水当量较高。我们的研究结果提供了一个当代基线，为保护和管理行动的制定与评估提供信息，并指导未来的调查工作。
