Ramírez-Alvarez Diego, Li Xinhai
Unidad de Vida Silvestre, Servicio Agrícola y Ganadero, Región de O'Higgins, Rancagua, Chile.
Key Laboratory of Animal Ecology and Conservation Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing, China.
PeerJ. 2025 Sep 1;13:e19946. doi: 10.7717/peerj.19946. eCollection 2025.
Species-specific density is an essential parameter for evaluating population stability and ecosystem health. We estimate the population density of native carnivores, South American gray and culpeo foxes ( spp.), guiña () and Andes skunk (), in central Chile, inferring on the potential influence of the availability of introduced exotic prey on their population dynamics.
Monitoring with camera traps was conducted from March 1, 2021, to March 31, 2022, across three distinct landscapes representative of the coastal mountain range of central Chile: Mediterranean coastal thorn forest, Mediterranean coastal sclerophyllous forest, and exotic monoculture tree plantations. We estimated density using an R package, cameratrapR, where animal movement was simulated using a correlated random walk within the camera grids. Simulations were run for a range of numbers of individuals, representing a gradient of population densities. We matched these results and the observed photo records using a machine learning algorithm, random forest, thereby estimating population density and its 95% confidence intervals.
A total of 10,046 trap days resulted in 9,120 photographs of carnivores, with 3,888 independent records. Our findings indicate that spp. are the carnivore species with the highest population density in central Chile (4.1-4.8 individuals/km). Furthermore, their density was higher in the exotic monoculture tree plantation ecotype compared to native forests, suggesting a dietary subsidy from non-native prey. We report the first population density estimates for (1.8-2.2 individuals/km) and (0.7-1.3 individuals/km) in the three landscapes, showing different habitat preferences and resource availabilities across landscapes. The results highlight the complex interactions between carnivores and their environments, particularly the role of exotic introduced species as prey items in shaping native carnivore populations. These findings also provide insights into carnivore adaptability and the implications for biodiversity conservation.
特定物种密度是评估种群稳定性和生态系统健康的重要参数。我们估计了智利中部本土食肉动物南美灰狐和 Culpeo 狐（ 属）、草原猫（ ）和安第斯臭鼬（ ）的种群密度，推断引入的外来猎物的可获得性对其种群动态的潜在影响。
于2021年3月1日至2022年3月31日，在代表智利中部沿海山脉的三种不同景观中使用相机陷阱进行监测：地中海沿海多刺森林、地中海沿海硬叶森林和外来单一栽培人工林。我们使用R包cameratrapR估计密度，其中动物运动是通过相机网格内的相关随机游走进行模拟的。针对一系列个体数量进行模拟，代表种群密度梯度。我们使用机器学习算法随机森林将这些结果与观察到的照片记录进行匹配，从而估计种群密度及其95%置信区间。
总共10,046个诱捕日产生了9,120张食肉动物照片，其中有3,
