Plant diversity and productivity experiments in European grasslands

Science

Volumn 286, Issue 5442, 1999, Pages 1123-1127

  Hector, A ^a   Schmid, B ^b   Beierkuhnlein, C ^c   Caldeira, M C ^d   Diemer, M ^b   Dimitrakopoulos, P G ^e   Finn, J A ^f,l   Freitas, H ^d,m   Giller, P S ^f   Good, J ^f   Harris, R ^f   Hogberg P ^g   Huss Danell, K ^g   Joshi, J ^b   Jumpponen, A ^g   Korner C ^h   Leadley, P W ^h,n   Loreau, M ⁱ   Minns, A ^a   Mulder, C P H ^g,o   O'Donovan, G ^f,p   Otway, S J ^a   Pereira, J S ^d   Prinz, A ^c   Read, D J ^j   Scherer Lorenzen, M ^k   Schulze, E D ^k   Siamantziouras, A S D ^e   Spehn, E M ^h   Terry, A C ^j   Troumbis, A Y ^e   Woodward, F I ^j   Yachi, S ^i,q   Lawton, J H ^a   more..

^a NATURAL ENVIRONMENT RESEARCH COUNCIL   (United Kingdom)

^b UNIVERSITY OF ZURICH   (Switzerland)

^c UNIVERSITY OF BAYREUTH   (Germany)

^d UNIVERSITY OF LISBON   (Portugal)

^e UNIVERSITY OF THE AEGEAN   (Greece)

^f UNIVERSITY COLLEGE CORK   (Ireland)

^g SWEDISH UNIVERSITY OF AGRICULTURAL SCIENCES   (Sweden)

^h UNIVERSITY OF BASEL   (Switzerland)

ⁱ ECOLE NORMALE SUPÉRIEURE   (France)

^j UNIVERSITY OF SHEFFIELD   (United Kingdom)

^k MAX PLANCK INSTITUTE FOR BIOGEOCHEMISTRY   (Germany)

^l UNIVERSITY OF READING   (United Kingdom)

^m UNIVERSITY OF COIMBRA   (Portugal)

ⁿ UNIVERSITÉ PARIS SACLAY   (France)

^o VICTORIA UNIVERSITY OF WELLINGTON   (New Zealand)

^p UNIVERSITY COLLEGE DUBLIN   (Ireland)

^q KYOTO UNIVERSITY   (Japan)

more..

Author keywords

[No Author keywords available]

Indexed keywords

BIODIVERSITY; GRASSLAND; PRODUCTIVITY;

ARTICLE; BIODIVERSITY; BIOMASS; ECOLOGY; GEOGRAPHY; PLANT; PRIORITY JOURNAL; SPECIES DIFFERENCE;

EUROPE;

EID: 0033527614     PISSN: 00368075     EISSN: None     Source Type: Journal    
DOI: 10.1126/science.286.5442.1123     Document Type: Article

References (44)

1. Nature's Services, G. C Daily, Ed. (Island Press, Washington, DC, 1997).
2. S. Naeem, L. J. Thompson, S. P. Lawler, J. H. Lawton, R. M. Woodfin, Nature 368, 734 (1994).
3. S. Naeem, K. He̊kansson, J. H. Lawton, M. J. Crawley, L. J. Thompson, Oikos 76, 259 (1996); A. J. Symstad, D. Tilman, J. Willson, J. M. H. Knops, Oikos 81, 389 (1998).
4. S. Naeem, K. He̊kansson, J. H. Lawton, M. J. Crawley, L. J. Thompson, Oikos 76, 259 (1996); A. J. Symstad, D. Tilman, J. Willson, J. M. H. Knops, Oikos 81, 389 (1998).
5. D. Tilman, D. Wedin, J. Knops, Nature 379, 718 (1995).
6. D. Tilman et al., Science 277, 1300 (1997).
7. D. U. Hooper and P. M. Vitousek, Science 277, 1302 (1997); D. U. Hooper, Ecology 79, 704 (1998); D. U. Hooper and P. M. Vitousek, Ecol. Monogr. 68, 121 (1998).
8. D. U. Hooper and P. M. Vitousek, Science 277, 1302 (1997); D. U. Hooper, Ecology 79, 704 (1998); D. U. Hooper and P. M. Vitousek, Ecol. Monogr. 68, 121 (1998).
9. D. U. Hooper and P. M. Vitousek, Science 277, 1302 (1997); D. U. Hooper, Ecology 79, 704 (1998); D. U. Hooper and P. M. Vitousek, Ecol. Monogr. 68, 121 (1998).
10. G. W. Allison, Am. Nat. 153, 26 (1999).
11. M. A. Huston, Oecologia 110, 449 (1997).
12. J. P. Grime, Science 277, 1260 (1997).
13. L. W. Aarssen, Oikos 80, 183 (1997).
14. J. G. Hodgson, K. Thompson, P. J. Wilson, A. Bogaard, Funct. Ecol. 12, 843 (1998).
15. A. Hector, Oikos 82, 597 (1998).
16. M. Loreau, Oikos 82, 600 (1998).
17. J. H. Lawton, S. Naeem, L. J. Thompson, A. Hector, M. J. Crawley, Funct Ecol. 12, 848 (1998).
18. M. Diemer, J. Joshi, C. Körner, B. Schmid, E. Spehn, Bull. Geobot. Inst. ETH 63, 95 (1997); C. P. H. Mulder, J. Koricheva, K. Huss-Danell, P. Hôgberg, J. Joshi, Ecol. Lett. 2, 236 (1999); E. M. Spehn, J. Joshi, B. Schmid, M. Diemer, C. Körner, Funct. Ecol., in press.
19. M. Diemer, J. Joshi, C. Körner, B. Schmid, E. Spehn, Bull. Geobot. Inst. ETH 63, 95 (1997); C. P. H. Mulder, J. Koricheva, K. Huss-Danell, P. Hôgberg, J. Joshi, Ecol. Lett. 2, 236 (1999); E. M. Spehn, J. Joshi, B. Schmid, M. Diemer, C. Körner, Funct. Ecol., in press.
20. M. Diemer, J. Joshi, C. Körner, B. Schmid, E. Spehn, Bull. Geobot. Inst. ETH 63, 95 (1997); C. P. H. Mulder, J. Koricheva, K. Huss-Danell, P. Hôgberg, J. Joshi, Ecol. Lett. 2, 236 (1999); E. M. Spehn, J. Joshi, B. Schmid, M. Diemer, C. Körner, Funct. Ecol., in press.
21. Field experiments were established in spring 1995 in Switzerland, in autumn 1996 in Portugal, and in spring 1996 at all other sites. Plots 2 m by 2 m were seeded with 2000 seeds per square meter, divided equally between the number of species in each plant assemblage. Seeds were collected locally as far as possible or otherwise were purchased from national commercial sources, avoiding agricultural cultivars. Plots were regularly weeded to remove unwanted species.
22. D. Tilman, C. L. Lehman, K. T. Thomson, Proc. Natl. Acad. Sci. U.S.A 94, 1857 (1997).
23. T. J. Givnish, Nature 371, 113 (1994); D. Tilman, Oikos 80, 185 (1997).
24. T. J. Givnish, Nature 371, 113 (1994); D. Tilman, Oikos 80, 185 (1997).
25. 2 = 0.95, P < 0.001). The analyses reported here use the planned number of species. Analyses using actual numbers of species present in the second year of the experiment are not presented but also reveal highly significant effects of species richness and functional group richness.
26. 2 = 0.73).
27. H. A. Mooney, in Ecosystems of the World 11. Mediterranean-type Shrublands, F. di Castri, D. W. Goodall, R. L. Specht, Eds. (Elsevier Scientific, Amsterdam, 1981); F. di Castri and H. A. Mooney, Eds., Mediterranean-type Ecosystems: Origin and Structure (Springer-Verlag, Berlin, 1973).
28. H. A. Mooney, in Ecosystems of the World 11. Mediterranean-type Shrublands, F. di Castri, D. W. Goodall, R. L. Specht, Eds. (Elsevier Scientific, Amsterdam, 1981); F. di Castri and H. A. Mooney, Eds., Mediterranean-type Ecosystems: Origin and Structure (Springer-Verlag, Berlin, 1973).
29. Because species richness and functional group richness are unavoidably correlated, in statistical analyses it is impossible to unequivocally distinguish their relative effects [G. W. Allison, Am. Nat. 153, 26 (1999)]. We present the sequential analysis determined by our experimental design and a priori hypotheses, which addressed the effects of (i) species richness and (ii) functional group richness for a given number of species. Analyses used sequential backward selection of terms from the maximal model, which included sites, blocks within sites, species richness, functional group richness (within-species richness levels), plant assemblage, the locality-by-assemblage interaction, and the overall residual variation between plots within the above treatments. Locality-by-diversity interactions, the interaction of species, and functional group richness were also included but were never statistically significant and, for brevity, are not reported here.
30. M. Loreau, Proc. Natl. Acad. Sci. U.S.A. 95, 5632 (1998).
31. The percent of plant cover in each plot was visually estimated several times during each growing season and by the presence or absence of rooted individuals in 50 cells of a permanent quadrat measuring 1 m by 0.5 m. Productivity patterns could be associated with poor cover in low diversity assemblages, which may arise from poor plant establishment [M. A. Huston, Oecologia 110, 449 (1997)]. The analysis and ecological interpretation of this issue are complex, but low levels of cover in the unmanipulated reference plots at some of our sites (sometimes 50% at the annual-dominated Portuguese field site) provide evidence against the automatic exclusion of plots with low cover.
32. J. H. Lawton, Oikos 71, 357 (1994); S. Naeem, J. H. lawton, L. J. Lindsey, S. P. lawler, R. M. Woodfin, Endeavour 19, 58 (1995); F. Schläpfer, B. Schmid, I. Seidl. Oikos 84, 346 (1999).
33. J. H. Lawton, Oikos 71, 357 (1994); S. Naeem, J. H. lawton, L. J. Lindsey, S. P. lawler, R. M. Woodfin, Endeavour 19, 58 (1995); F. Schläpfer, B. Schmid, I. Seidl. Oikos 84, 346 (1999).
34. J. H. Lawton, Oikos 71, 357 (1994); S. Naeem, J. H. lawton, L. J. Lindsey, S. P. lawler, R. M. Woodfin, Endeavour 19, 58 (1995); F. Schläpfer, B. Schmid, I. Seidl. Oikos 84, 346 (1999).
35. Data from the third year of the experiment have been processed for all sites except Portugal. Although there still appears to be no response in Greece, much of the other variation shown in Fig. 2 has disappeared, and the overall pattern appears to match the general log-linear relation more closely than in year two.
36. D. A. Wardle, O. Zackrisson, G. Hörnberg, C. Gallet, Science 277, 1296 (1997); D. Tilman et al., Science 278, 1866 (1997).
37. D. A. Wardle, O. Zackrisson, G. Hörnberg, C. Gallet, Science 277, 1296 (1997); D. Tilman et al., Science 278, 1866 (1997).
38. 29,235 = 3.77, P < 0.001 (Table 3)].
39. Each species or functional group was added individually to the multiple regression models in Table 3. Fitting each species or group separately meant that the effect attributed to each was maximized. Our ability to test the effects of the grass functional group was limited, because most of the assemblages included grasses.
40. E. Garnier, M.-L. Navas, M. P. Austin, J. M. Lilley, R. M. Cifford, Acta Oecol. 18, 657 (1997).
41. 2 scale) after adjusting for differences between locations and blocks by taking residuals from analyses with these terms [seven of the species showed significantly different responses at different sites (Table 4)]. We expected slopes of zero where intraspecific competition was equal to competition with other species and expected positive and negative slopes where it was more and less intense, respectively. Under the sampling hypothesis, we expected approximately equal distributions of positive and negative slopes. In contrast, 12 of the 14 species had slopes that were positive; 8 significantly so. Two species had slopes that were negative, but neither was significantly different from zero.
42. J. L. Harper, Population Biology of Plants (Academic Press, London, 1977).
43. We identified the species with the highest biomass in each plant assemblage and, where data were available (271 of the 308 polycultures), compared their average monoculture biomass with the biomass of the total assemblage using the overyielding index Dmax [M. Loreau, Oikos 82, 600 (1998)], where Dmax = (total biomass of a plant assemblage-average monoculture biomass of the dominant species in that assemblage)/average monoculture biomass of the dominant species in that assemblage. We analyzed Dmax after transformation using natural logarithms (after adding 1 to make all values positive) to meet the assumptions of parametric analyses.
44. The BIODEPTH project is funded by the European Commission within the Framework IV Environment and Climate program (ENV-CT95-0008). Many colleagues too numerous to list have assisted with the project; in particular, we thank P. Heads and E. BazeleyWhite. We thank J. Neider for advice on statistical analyses.