The environmental and biotic context within which plants grow have a great potential to modify responses to climatic changes, yet few studies have addressed both the direct effects of climate and the modulating roles played by variation in the biotic (e.g. competitors) and abiotic (e.g. soils) environment.
Eskelinen and Harrison investigate how the effects of enhanced rainfall are modulated by above-ground competition and by edaphic variables for two grassland plants, Lasthenia californica and Calycadenia pauciflora. They find that increased competition outweighs the direct positive impacts of enhanced rainfall on most fitness measures for both species, resulting in no net effect of enhanced rainfall. Both species benefit from enhanced rainfall when the absence of competitors is accompanied by high soil water retention capacity. They conclude that the results emphasize the importance of considering abiotic as well as biotic context when making future climate change forecasts.
This article appears in the special issue Plants and Climate Change.