Grassland Vegetation Changes and Nocturnal Global Warming

Abstract

Global minimum temperatures (T _MIN) are increasing faster than maximum temperatures, but the ecological consequences of this are largely unexplored. Long-term data sets from the shortgrass steppe were used to identify correlations betweenT _MIN and several vegetation variables. This ecosystem is potentially sensitive to increases inT _MIN. Most notably, increased springT _MIN was correlated with decreased net primary production by the dominant C₄ grass (Bouteloua gracilis) and with increased abundance and production by exotic and native C₃ forbs. Reductions in B. gracilismay make this system more vulnerable to invasion by exotic species and less tolerant of drought and grazing.