Climate variability and trends in climate extremes in the priority conservation area El Tokio and adjacent areas in northeastern Mexico

Abstract

El Tokio, a priority conservation area in Mexico and North America, and its adjacent areas hold the world's last remaining colonies of the Mexican Black-tailed Prairie Dog (Cynomys mexicanus) and serve as home to over 250 bird species, including global wintering grassland birds of high conservation concern, and other rare, endemic and endangered species of flora and fauna. While alarming changes in distribution and migration patterns of species existing in the study area have been reported, studies on the role of climate in these changes are scarce, partly because of the lack of climate information. To fill this gap, this study defined the climate types and eight bioclimatic variables of five ecoregions within and adjacent to El Tokio and analyzed climate indices showing trends of climate extremes, using 30-year climate data and the software RClimDex 1.0 RCs. Results showed climate variability in the study area, with 14 climate types, mostly arid and semi-arid. The analysis of bioclimatic variables showed that the Plains of Zacatecano-Potosino Plateau ecoregion, which contains prairie dog colonies, had the highest annual and mean temperature in the most humid, driest and hottest trimesters of the year; its precipitation had lower seasonality in relation to other ecoregions. Climate indices to detect trends in climate extremes showed greater intensity in precipitation, but also longer dry intervals during the year in the Plains of Zacatecano-Potosno Plateau, while the adjacent Sierra with Forests ecoregion, which borders some colonies, showed trends of warmer winters, summers with fewer days with high minimum temperatures, and precipitation that was less in amount and intensity. The generated climate datasets and analyses contribute essential input for climate change studies and for biological studies and conservation programs for the species and ecosystems present in the biologically rich study area, some of which are greatly threatened and of international concern. Keywords: Bioclimatic variables, Climatic change, Climate indices, Endangered species, Prairie dog, El Tokio, Mexico, Priority conservation area, Migratory birds