Germination Under elevated temperatures: A controlled experiment for Chihuahuan Desert grasses common in northern Mexico

Global temperature is expected to continue increasing, affecting the ability of plants to grow and develop. It is imperative to test plant responses to better select species that can be used for ecological restoration and to predict exotic plant interactions in severely damaged ecosystems such as the Chihuahuan Desert of northern Mexico. The objective of this work was to evaluate germination development in six native species and three exotic species commonly occurring in this area under increasing temperatures. We used a thermogradient table to test temperatures of 14°C, 18°C, 22°C, 26°C, 30°C, and 34°C in a laboratory setting. The native grasses Bouteloua curtipendula, Bouteloua dactyloides, Bouteloua eriopoda , and Disakisperma dubium, as well as the exotic Eragrostis curvula and Eragrostis superba, showed a maximum germination peak between 22°C and 26°C and a subsequent decline in germination after 30°C. The native Bouteloua gracilis and Digitaria californica, as well as the exotic Cynodon dactylon, showed greater germination tolerance to increasing temperatures than the other species. We suggest that B. gracilis and D. californica are used in revegetation projects where high temperatures are a concern. On the other hand, C. dactylon may become a more aggressive competitor with native grasses in environments with higher temperatures.