Impact of climate change on the Andean distribution of Poa scaberula (Poaceae)

Abstract

Grasslands play an important ecological role and are the dominant landscape in the whole extent of the Andes and high elevation regions of South America. Climate change models indicate a strong impact on mountain systems. The climatic conditions of mountain systems are greatly influenced by topography and elevation. Poa scaberula Hook. f. is an Andean grass and its habitat may be threatened by climate change and human practices. Species distribution models, using bioclimatic variables, are often used to predict the future distribution and environmental requirements of species. In this study we prepared two bioclimatic models for P. scaberula using the Maxent algorithm, the first based on the inclusion of the variable elevation (E +) and the second on the exclusion of elevation (E-) to identify the main environmental variables for habitat suitability shift, to examine changes in the extent of the area of suitable habitat under current and future climate scenarios, and to project and quantify the spatial pattern of shifts in the areal extent of suitable habitat under future climate conditions. We then compared both projections and evaluate the contribution of the elevation variable in the performance of the models. We observed that the inclusion of elevation decreased the performance of the models. In models with omission of the elevation mean cold hardiness, temperature seasonality and annual mean temperature emerge as the critical factors shaping habitat suitability for P. scaberula. Under the low and higher concentration greenhouse gas emissions scenario, the range of the species may decrease as global warming intensifies. The information gained from this study should be an useful reference for development biogeographic studies and the impact of global warming on regions of high elevations, and contribute to implement conservation and management strategies for Andean grassland and high elevation grasslands.