A test of alternative stable states theory in producer communities of temporary wetlands

Background/Question/Methods:
Discontinuous variation in community structure over space and time is present in many natural systems. One theory attributes this variation to the existence of alternative stable states, suggesting that two or more possible community structures are equally likely in certain environmental conditions. I performed survey work and a mesocosm experiment to test the applicability of alternative stable states theory to the producer communities of temporary wetlands. The mesocosm experiment was performed to test the divergence of artificial communities into alternative community states. I manipulated nutrient and light levels (potential controls identified from my survey work) and initial densities of a dominant producer (floating plants Lemnaceae) in a factorial experiment.

Results/Conclusions:

My observational work shows that several community states exist in these systems, characterized by different dominant producer functional groups. Analysis of the experimental data so far suggests that mesocosms with higher nutrient levels were more likely to develop floating plant dominance, but light levels also affected floating plant abundance in the low initial density treatments. Combined with other studies, this work will improve our understanding of the existence, controls, and consequences of alternative community states in temporary wetlands, and it will inform management of floating plant outbreaks.