Using hierarchical spatial models to assess the occurrence of an island endemism: the case of Salamandra corsica

Abstract

Background: Island species are vulnerable to rapid extinction, so it is important to develop accurate methods to determine their occurrence and habitat preferences. In this study, we assessed two methods for modeling the occurrence of the Corsican endemic Salamandra corsica, based on macro-ecological and fine habitat descriptors. We expected that models based on habitat descriptors would better estimate S. corsica occurrence, because its distribution could be influenced by micro-environmental gradients. The occurrence of S. corsica was modeled according to two ensembles of variables using random forests. Results: Salamandra corsica was mainly found in forested habitats, with a complex vertical structure. These habitats are associated with more stable environmental conditions. The model based on fine habitat descriptors was better able to predict occurrence, and gave no false negatives. The model based on macro-ecological variables underestimated the occurrence of the species on its ecological boundary, which is important as such locations may facilitate interpopulation connectivity. Conclusions: Implementing fine spatial resolution models requires greater investment of resources, but this is advisable for study of microendemic species, where it is important to reduce type II error (false negatives).

Vegetation cover and occurrence of salamanders in the western Mediterranean

“…2010; Ben Hassine & Nouira 2012; Ben Hassine et al . 2016; Ben Hassine & Escoriza 2017; Seglie 2018; Escoriza & Hernandez 2019; Cruciti et al . 2020; Escoriza et al .…”

“…The specimens were detected during diurnal and nocturnal surveys involving visual transects, road transects, and rock/log flipping. We also included some previously reported records (Lanza et al 2005;Manenti 2005;Malori et al 2010;Ben Hassine & Nouira 2012;Ben Hassine et al 2016;Seglie 2018;Escoriza & Hernandez 2019;Cruciti et al 2020;Escoriza et al 2020) if the location could be determined with sufficient precision (Tables S1 and S2).…”

Population genomics of Corsican wildcats: Paving the way toward a new subspecies within the Felis silvestris spp. complex?

“…If confirmed as a wild entity, Corsican wildcat conservation would also favour the preservation of numerous other species and habitat types since, like many carnivores, wildcats are an umbrella species (Jerosch et al, 2009, 2018; Noss et al, 1996; Virgos et al, 2002). It is a critical point since islands of the Mediterranean Basin are biodiversity hotspots hosting many endemic species (e.g., Escoriza & Hernandez, 2019; Grill et al, 2007; Jeanmonod et al, 2015) and particularly threatened by climate change (Courchamp et al, 2014; Ducrocq, 2016; Giorgi, 2006; Myers et al, 2000).…”

“…It is a critical point since islands of the Mediterranean Basin are biodiversity hotspots hosting many endemic species (e.g., Escoriza & Hernandez, 2019;Grill et al, 2007;Jeanmonod et al, 2015) and particularly threatened by climate change (Courchamp et al, 2014;Ducrocq, 2016;Giorgi, 2006;Myers et al, 2000).…”