Funções de sustentação múltipla de ecosistema em comunidades de savanas requer maior biodiversidade

terça-feira, janeiro 05, 2010

Sustaining multiple ecosystem functions in grassland communities requires higher biodiversity

Erika S. Zavaleta a,1, Jae R. Pasari a, Kristin B. Hulvey a and G. David Tilman b,1

- Author Affiliations

aEnvironmental Studies Department, University of California, Santa Cruz, CA 95064

bDepartment of Ecology, Evolution and Behavior, University of Minnesota, St. Paul, MN 55108

Contributed by G. David Tilman, November 20, 2009 (sent for review July 27, 2009)

Abstract

Society places value on the multiple functions of ecosystems from soil fertility to erosion control to wildlife-carrying capacity, and these functions are potentially threatened by ongoing biodiversity losses. Recent empirically based models using individual species’ traits suggest that higher species richness is required to provide multiple ecosystem functions. However, no study to date has analyzed the observed functionality of communities of interacting species over multiple temporal scales to assess the relationship between biodiversity and multifunctionality. We use data from the longest-running biodiversity-functioning field experiment to date to test how species diversity affects the ability of grassland ecosystems to provide threshold levels of up to eight ecosystem functions simultaneously. Across years and every combination of ecosystem functions, minimum-required species richness consistently increases with the number of functions considered. Moreover, tradeoffs between functions and variability among years prevent any one community type from providing high levels of multiple functions, regardless of its diversity. Sustained multifunctionality, therefore, likely requires both higher species richness than single ecosystem functionality and a diversity of species assemblages across the landscape.

Cedar Creek multifunctionality species richness tradeoffs

Footnotes

1To whom correspondence may be addressed. E-mail: zavaleta@ucsc.edu or tilman@umn.edu.

Author contributions: G.D.T. designed research; G.D.T. performed research; E.S.Z., J.R.P., and K.B.H. analyzed data; and E.S.Z., J.R.P., and K.B.H. wrote the paper.

The authors declare no conflict of interest.

This article contains supporting information online at www.pnas.org/cgi/content/full/0906829107/DCSupplemental.

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