The effects of plant composition and diversity on ecosystem processes

Science

Volumn 277, Issue 5330, 1997, Pages 1302-1305

  Hooper, David U ^a,b   Vitousek, Peter M ^b  

^a UNIVERSITY OF CALIFORNIA   (United States)

^b STANFORD UNIVERSITY   (United States)

Author keywords

[No Author keywords available]

Indexed keywords

NITROGEN;

COMMUNITY COMPOSITION; ECOSYSTEM PROCESS; FUNCTIONAL GROUP; NITROGEN; PRIMARY PRODUCTIVITY; SPECIES DIVERSITY;

ARTICLE; BIODIVERSITY; ECOSYSTEM; ENVIRONMENTAL MANAGEMENT; NITROGEN FIXATION; NONHUMAN; PLANT; PRIORITY JOURNAL; SOIL;

EID: 0030846289     PISSN: 00368075     EISSN: None     Source Type: Journal    
DOI: 10.1126/science.277.5330.1302     Document Type: Article

References (43)

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14. Functional groups are groupings of species based on physiology, morphology, life history, or other traits relevant to controls on an ecosystem process; classification will depend on the process under investigation. Although functional groups are not always clearcut, they help to elucidate mechanisms by which species influence ecosystem processes, help to generalize such mechanisms across species, and help to simplify studies in systems with a large diversity of species [P. M. Vitousek and D. U. Hooper, in Biodiversity and Ecosystem Function, E.-D. Schulze and H. A. Mooney, Eds. (Springer-Verlag, Berlin, 1993), pp. 3-14; S. E. Hobbie, D. B. Jensen, F. S. Chapin III, ibid., pp. 385-408; C. Körner, ibid., pp. 117-140].
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23. We measured aboveground biomass by clipping annual species at the soil surface in five randomly placed 10 cm by 10 cm quadrats in each plot. For P's, we measured diameter and height of random individuals within each plot, then determined regressions for these measurements, with aboveground biomass on randomly harvested individuals [D. U. Hooper, Ecology, in press]. Clippings were sorted by species, dried at 65°C, and weighed. Total aboveground biomass is the sum of measurements made at peak biomass for each functional group: April for E's and N's, May for P's, and September for L's.
24. 15N, where values for the bare plot are meaningless, we used a means model coding for the ANOVA to avoid confounding the results. In these cases, ANOVA main effects and interactions were tested with balanced comparisons among the remaining treatments [For details, see D. U. Hooper and P. M. Vitousek, Ecol. Monogr., in press].
25. 15N, where values for the bare plot are meaningless, we used a means model coding for the ANOVA to avoid confounding the results. In these cases, ANOVA main effects and interactions were tested with balanced comparisons among the remaining treatments [For details, see D. U. Hooper and P. M. Vitousek, Ecol. Monogr., in press].
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43. We thank Waste Management Inc. and the Center for Conservation Biology, Stanford University, for access to field sites. D. Turner, D. Herman, C. Chu, P. Brookes, M. Hanes, L. Jackson, M. A. Read, N. M. Holbrook, C. Benton, L. Chu, A. Cottrell, H. Farrington, M. Jones, D. Mallery, B. Tibble, M. Vandermarck, and E. Vela all provided valuable field and laboratory assistance. T. Chapin and J. Neff gave useful comments on earlier drafts of this manuscript. Financial support was provided by grants to D.U.H. from NSF (Predoctoral Fellowship and Doctoral Dissertation Improvement Grant DEB-9212995), from the Morrison Institute for Population and Resource Studies, and from the NASA/Stanford Program for Global Change. Additional support came from the Pew Scholars Program in Conservation and Environment and from the A. W. Mellon Foundation.