APPLICATION OF CLIMATE ENVELOPE MODELS AND GENERALIZED MIXED MODELS TO ANALYZE THE EFFECT OF CLIMATE CHANGE ON A KEY ENDANGERED SPECIES: THE CASE OF MICROTUS (IBEROMYS) CABRERAE

APPLICATION OF CLIMATE ENVELOPE MODELS AND GENERALIZED MIXED MODELS TO ANALYZE THE EFFECT OF CLIMATE CHANGE ON A KEY ENDANGERED SPECIES: THE CASE OF MICROTUS (IBEROMYS) CABRERAE Past climate changes have significantly impacted global biodiversity and natural ecosystems. Furthermore, anthropic influences derived from human activities such as agriculture and construction also affect species distribution and populations worldwide. Microtus (Iberomys) cabrerae is an endangered small mammal endemic from the Iberian Peninsula with a continuous paleontological record and high sensitivity to climatic variations that is currently experiencing population decline. With this study, we wanted to delve into the factors driving the actual conservation of this species. We reconstructed the historical distribution of the species based on fossil records across isotopic and cultural periods. Then, we modeled its historical climatic distributions from the Late Pleistocene to the present using bioclimatic niche models. Additionally, we quantified changes in historical climatic distributions through statistical analysis using Generalized Linear Mixed-Effects Models. Current and paleogeographic distribution The current distribution was mapped using a vector layer from the IUCN Red List database (IUCN 2023) (http://www.iucnredlist.org/) (Fernandes et al., 2019), projected in EPSG 4326 format. Paleobiogeographic distribution according to isotopic periods and cultural periods was mapped based on fossil records documented in previous studies (Sevilla & Laplana, 2013; Domínguez-García et al., 2023; Arjanto et al., 2023; López-García et al., 2021; Conolly et al., 2019; Fagoaga et al., 2018). A total of 159 sites were identified, with records spanning from MIS 5 (~130-75 Kyr) to MIS 1 (~14.7 Kyr – sub-recent) (Tables S1 and S2). Climatic characterization To obtain a raster layer that reflects the climatic conditions in which this species can live, we characterize the climatic niche of M. (Iberomys) cabrerae by the selection of 6 out of the 18 bioclimatic variables available from WorldClim (http://www.worldclim.org/) (Fick & Hijmans, 2017) (Table 1). These variables were chosen to represent the optimal climatic conditions for this species. Values for the 6 Bioclimatic variables were extracted from the areas that conformed the current distribution of M. (Iberomys) cabrerae, obtaining the ranges in which it can live. Modeling historical climatic distribution Climatic layers for each period were obtained from the ecoClimate database, which provides past, present, and future climatic layers (Varela et al., 2015; Lima-Ribeiro et al., 2015). These raster layers are based on the CCSM4 climatic model and are available for four past time intervals: the Last Interglacial Period (LIP, ~130–116 kyr) at a spatial resolution of 2.5 arc-minutes; the Last Glacial Maximum (LGM, ~23–-13 Kyr of 2.5 minutes; Early Holocene period ~ 11.7-6 Kyr of 30 seconds and Sub-recent period ~ 6 Kyr - Act. of 30 seconds.