PARENT SESSION
Poster Session #64: Long Term Ecological Research.
Friday, August 9. Presentation from 8:00 AM to 9:30 AM. Exhibit Hall B & C, TCC

Diversity and stability in natural systems: findings from wetland plant communities in Minnesota.

Nichols, John^*,1, Phillips, Martha², Lehman, Clarence³, ¹ University of North Carolina - Chapel Hill, Chapel Hill, NC² The College of St. Catherine, St. Paul, MN³ University of Minnesota, St. Paul, MN

ABSTRACT- The links between biodiversity and ecosystem properties have become the focus of much attention in light of current declines in biodiversity. The Diversity-Stability Hypothesis, which suggests that such declines could reduce the stability of ecosystem processes, has been rejuvenated by a number of recent theoretical and experimental studies. However, the relationship between diversity and stability in naturally occurring communities has yet to be as thoroughly examined. We examined this relationship using an 11-year observational record of wetland plant communities within the Cedar Creek Natural History Area, Minnesota. Temporal stability, which measures the degree of year-to-year constancy in plant cover, was examined for each of eighteen sites. Community temporal stability increased with both the community species richness and the Shannon-Weaver index of diversity; however, community plant cover did not increase with diversity. Thus, we reason that the observed association between diversity and stability must result from strong negative co-variances in species fluctuations and/or a statistical averaging effect. In contrast to the observed relationship for community-level stability, the temporal stabilities of individual populations within our communities showed a slight but insignificant decrease with diversity. These results are consistent with recent experimental and theoretical findings, and provide some of the first evidence for a link between diversity and stability in naturally occurring systems. This discovery thus advances our understanding of the possible changes in ecosystems worldwide associated with declines in their biodiversity.

KEY WORDS: diversity, stability, community, wetland