Effects of global change on Mojave Desert annual plant communities

The objective of this research was to investigate the potential effects of global change on Mojave Desert annual plant communities. The predicted changes of increased summer precipitation, increased nitrogen deposition, and biological soil crust disturbance were simulated in a full factorial design, and the effects on species composition, plant density, plant size, and nitrogen content were measured. Added summer rain decreased community-level biomass and diversity the following spring, while increased nitrogen deposition and biological soil crust disturbance increased community-level biomass and diversity. However, biomass responses at the species level were highly variable and individualistic, consistent with the episodic nature of desert annual plant communities in both space and time. Results of this study demonstrate that responses to global change are complex, species-dependent, and vary with resource availability, but overall trends at the community level are detectable and potentially predictable