PARENT SESSION
Session #10: Functional similarity and functional groups in ecological systems. Organized by: P. Morin and R. Zamora.
Tuesday, August 7, 2001. Lecture Hall
Functional versus species richness in ecosystem response to global change: can they be disentangled?
Naeem, Shahid1, Knops, Johannes2, Reich, Peter3, Tilman, David3, Craine, Joe4, Wedin, David2, 1 2 3 4
ABSTRACT- An ecosystem's biota regulates ecosystem response to anthropogenic modifications of biogeochemical processes (henceforth "global change"). Therefore dramatic changes in an ecosystem's biota, such as biodiversity loss, should have significant impacts on an ecosystem's response to global change. Understanding and predicting the consequences of biodiversity loss, however, requires identifying the mechanism of an ecosystem's response and the relevant functional component of an ecosystem's biodiversity that affects this mechanism. Using the BioCON free-air carbon dioxide enrichment system at Cedar Creek, Minnesota, USA, we examined how grassland plots responded to changes in carbon dioxide and nitrogen deposition. We simultaneously manipulated functional and taxonomic plant diversity to determine the relative roles of these two components of plant biodiversity in governing ecosystem response to global change. While the mechanism was plant-mediated, and below-ground response variables such as decomposition, microbial biomass, prokaryotic density, and sole source carbon use profiles responded significantly to the manipulation of carbon dioxide and nitrogen, determining the relative importance of plant functional richness versus plant species richness was not possible because the two were correlated. To the extent that such correlations exist in nature, it may be neither possible nor necessary to distinguish between functional and species richness in biodiversity studies.
KEY WORDS: biodiversity, functional, ecosystem, grassland