Department of Environmental Science and Policy, Università degli Studi di Milano, Via Celoria 10, Milan, 20133, Italy.
Univ. Grenoble Alpes, Univ. Savoie Mont Blanc, CNRS, LECA (Laboratoire d'Écologie Alpine), Grenoble, F-38000, France.
Conserv Biol. 2021 Oct;35(5):1530-1539. doi: 10.1111/cobi.13686. Epub 2021 Mar 16.
Many organisms live in networks of local populations connected by dispersing individuals, called spatially structured populations (SSPs), where the long-term persistence of the entire network is determined by the balance between 2 processes acting at the scale of local populations: extinction and colonization. When multiple threats act on an SSP, a comparison of the different factors determining local extinctions and colonizations is essential to plan sound conservation actions. We assessed the drivers of long-term population dynamics of multiple amphibian species at the regional scale. We used dynamic occupancy models within a Bayesian framework to identify the factors determining persistence and colonization of local populations. Because connectivity among patches is fundamental to SSPs dynamics, we considered 2 measures of connectivity acting on each focal patch: incidence of the focal species and incidence of invasive crayfish. We used meta-analysis to summarize the effect of different drivers at the community level. Persistence and colonization of local populations were jointly determined by factors acting at different scales. Persistence probability was positively related to the area and the permanence of wetlands, whereas it was negatively related to occurrence of fish. Colonization probability was highest in semipermanent wetlands and in sites with a high incidence of the focal species in nearby sites, whereas it showed a negative relationship with the incidence of invasive crayfish in the landscape. By analyzing long-term data on amphibian population dynamics, we found a strong effect of some classic features commonly used in SSP studies, such as patch area and focal species incidence. The presence of an invasive non-native species at the landscape scale emerged as one of the strongest drivers of colonization dynamics, suggesting that studies on SSPs should consider different connectivity measures more frequently, such as the incidence of predators, especially when dealing with biological invasions.
许多生物生活在由个体扩散连接的局部种群网络中，这些个体被称为具有空间结构的种群（SSP），整个网络的长期持续存在取决于在局部种群规模上起作用的两个过程之间的平衡：灭绝和定居。当多个威胁作用于 SSP 时，比较决定局部灭绝和定居的不同因素对于规划合理的保护行动至关重要。我们在区域尺度上评估了多个两栖物种的长期种群动态的驱动因素。我们使用贝叶斯框架内的动态占有模型来确定决定局部种群持续存在和定居的因素。由于斑块之间的连通性对 SSP 动态至关重要，因此我们考虑了作用于每个焦点斑块的 2 个连通性度量：焦点物种的发生率和入侵小龙虾的发生率。我们使用荟萃分析来概括社区水平上不同驱动因素的影响。局部种群的持续存在和定居是由不同尺度上的因素共同决定的。持续存在的概率与湿地的面积和持久性呈正相关，而与鱼类的出现呈负相关。在半永久性湿地和附近具有高焦点物种发生率的地点，定居概率最高，而在景观中入侵小龙虾发生率较高的地方，定居概率则较低。通过分析关于两栖动物种群动态的长期数据，我们发现一些经典特征对种群动态有很强的影响，这些特征通常用于 SSP 研究，例如斑块面积和焦点物种的发生率。景观尺度上入侵非本地物种的存在成为定居动态的最强驱动因素之一，这表明 SSP 研究应更频繁地考虑不同的连通性度量，例如捕食者的发生率，尤其是在处理生物入侵时。
