Forecasting the fate of high mountain ponds in the Andean region under future climate change

Abstract

The aims of this study are (i) to identify areas in the Andean region where the climate will remain stable enough for the survival of the study species; (ii) to analyze how climate change will affect these areas under different climate scenarios; (iii) to generate spatially explicit predictive maps of the expansion or retraction of these areas; and (iv) based on this information, to identify areas with priority for conservation. The analysis was performed using presenceonly data for 14 Heteroptera and Odonata species. Current and future models were developed to identify areas where the climate would be suitable for small ponds, using Maxent v3.3.3k, with future models based on three different Global Climate Models for the 2050 period (scenarios A2a and B2a). Model performance was evaluated using the jackknife approach. Climatic niche breadth and climatic niche similarities were calculated through Levin’s concentration metrics and the I statistic index (implemented in ENMTools), respectively. Maxent logistic outputs were converted into binary presence/absence maps, based on the ‘minimum training presence logistic threshold’, and used to build species richness maps for each condition considered (present and future). Current and future models with areas climatically suitable for small ponds were developed. All the study species proved to be narrow specialists and share similar climatic spaces. Our projections suggest that four of the species would not find suitable climate conditions for survival in the future. The priority area for conservation, where most species would find suitable climate conditions, is located between 33–47°S and 73–70°W. We identified future loss of the priority area towards the east and a small gain towards the north and south. The most probable situation for the year 2050 is a negative precipitation–evapotranspiration balance, and small ponds will probably be very short-lived or dry completely during summer, suggesting a drastic change in species assemblages and species richness of the region, which could become a hotspot of extinction.