PARENT SESSION
Oral Session # 75: Biodiversity II.
Presiding: K Kirkman
Thursday, August 7. 1:30 PM to 5:00 PM, SITCC Meeting Room 100.

Phenotypic diversity affects ecosystem functioning in the presence of another species.

Madritch, Michael^{*,1, 2}, Hunter, Mark¹, ¹ Institute of Ecology, Athens, GA, USA² Department of Entomology, Madison, WI, USA

ABSTRACT- We have previously demonstrated that intraspecific phenotypic diversity of leaf litter can influence ecosystem functioning during litter decomposition in the field. It is unknown whether the effects of phenotypic diversity persist when litter from additional species is present. We used laboratory microcosms to determine whether the intraspecific diversity effects of turkey oak leaf litter on nutrient dynamics are masked by the presence of naturally co-occurring longleaf pine litter. We varied the phenotypic diversity of oak litter (1, 3, and 6 phenotype combinations) in the presence and absence of pine litter and measured fluxes of carbon and nitrogen over a 42 week period. Soil C:N ratio peaked at intermediate levels of oak phenotypic diversity whereas the total amount of DOC leached from microcosms declined as oak phenotypic diversity increased. In no case did the presence or absence of pine litter influence the response of nutrient fluxes to changes in oak litter diversity. Our results indicate that phenotypic diversity influences ecosystem function even in the presence of another species, and suggest that conservation efforts should consider both inter- and intraspecific diversity.

Key words: decomposition, biodiversity, nutrient cycling