Abstract
One of the few important empirical generalizations regarding herbaceous plant systems has been the demonstration that species richness is related to standing crop with maximum richness occurring at moderate levels of standing crop. This relationship is normally demonstrated by comparing among vegetation types (i.e., vegetation with different dominants). We undertook this study to test whether the species richness-standing crop relationship was evident at a finer-grained level of organization, the within vegetation type level. Fifteen wetland sites were sampled in eastern Canada and species richness and standing crop determined in each of 224 0.25 m2 quadrats. Each site was relatively homogeneous in terms of the dominant species present and were therefore categorized as single vegetation types. However, as a group, the sites comprised a wide range of vegetation types.
A second order polynomial regression indicated a significant bitonic relationship between species richness and standing crop at the among-vegetation types scale, that is, when all 15 sites were combined. At the within-vegetation type level, however, no significant relationships were observed (p>0.05). The results indicate that the model of species richness proposed by Grime has predictive power at a coarse-grained level of organization, among vegetation types, but does not survive the transition to a finer-grained level of organization, the within vegetation type level. Therefore, the higher level processes which structure species richness patterns among vegetation types are not the same processes which determine richness patterns within a vegetation type.
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References
Aarssen L. W., Turkington R. & Cavers P. B. 1979. Neighbour relationships in grass-legume communities. II. Temporal stability and community evolution. Can. J. Bot. 57: 2695–2703.
Allen T. F. H. & Starr T. B. 1982. Hierarchy. The University of Chicago Press, Chicago.
Allen T. F. H. 1987. Hierarchical complexity in ecology: a noneuclidean conception of the data space. Vegetatio 69: 17–25.
Al-Mufti M. M., Sydes C. L., Furness S. B., Grime J. P. & Band S. R. 1977. A quantitative analysis of shoot phenology and dominance in herbaceous vegetation. J. Ecol. 65: 759–791.
Austin M. P. 1985. Continuum concept, ordination methods, and niche theory. Ann. Rev. Ecol. Syst. 16: 39–61.
Bond W. 1983. On alpha diversity and the richness of the Cape Flora: a study in Southern Cape Fynbos. In: Kruger F. S., Mitchell D. T. & Jarvis J. V. M. (eds), Mediterranean-type ecosystems: the role of nutrients. Springer-Verlag, Berlin.
Connell J. H. 1978. Diversity in tropical rain forests and coral reefs: high diversity of trees and corals is maintained only in a non-equilibrium state. Science 199: 1302–1309.
Day R. T., Keddy P. A., McNeill J. M. & Carleton T. J. 1988. Fertility and disturbance gradients: a summary model for riverine marsh vegetation. Ecology 69: 1044–1054.
Gaudet C. L. & Keddy P. A. 1988. Predicting competitive abilities from plant traits: a comparative approach. Nature 334: 242–243.
Gleason H. A. & Cronquist A. 1963. Manual of vascular plants of northeastern United States and adjacent Canada. Willard Grant, Boston.
Grime J. P. 1973. Competitive exclusion in herbaceous vegetation. Nature 242: 344–347.
Grime J. P. 1979. Plant strategies and vegetation processes. John Wiley & Sons, Chichester.
Grover J. P. 1988. Dynamics of competition in a variable environment: experiments with two diatom species. Ecology 69: 408–417.
Grubb P. J. 1977. The maintenance of species-richness in plant communities: the importance of the regeneration niche. Biol. Rev. 52: 107–145.
Grubb P. J. 1985. Plant populations and vegetation in relation to habitat, disturbance and competition: problems of generalization. In: White J. (ed.), The population structure of vegetation. Junk, Dordrecht.
Harner R. F. & Harper K. T. 1976. The role of area, heterogeneity, and favourability in plant species diversity of pinyon-juniper ecosystems. Ecology 57: 1254–1263.
Harper J. L. 1982. After description. In: Newman E. I. (ed.), The plant community as a working mechanism. Blackwell, Oxford.
Heads P. A. & Lawton J. H. 1982. Studies on the natural enemy complex of the holly leaf-miner: the effects of scale on the detection of aggregative responses and the implications for biological control. Oikos 40: 267–276.
Holling C. S. 1986. The resilience of terrestrial ecosystems; local surprise and global change. In: Clark W. C. & Munn R. E. (eds), Sustainable development of the biosphere. Cambridge Univ. Press, Cambridge.
Huston M. 1979. A general hypothesis of species diversity. Am. Nat. 113: 81–101.
Janzen D. H. 1970. Herbivores and the number of tree species in tropical forests. Am. Nat. 104: 501–528.
Keddy P. A. 1983. Shoreline vegetation in Axe Lake, Ontario: effects of exposure on zonation patterns. Ecology 64: 331–344.
Keddy P. A. 1987. Beyond reductionism and scholasticism in plant community ecology. Vegetatio 69: 209–211.
Keddy P. A. 1989. Competitive hierarchies and centrifugal organization in plant communities. In: Grace J. & Tilman D. (eds), Perspectives on plant competition. Academic Press, N.Y.
Lubchenco J. 1978. Plant species diversity in a marine intertidal community: importance of herbivore food preference and algal competitive abilities. Am. Nat. 112: 23–39.
Moore, D. R. J., Keddy, P. A., Gaudet, C. L. & Wisheu, I. C. in press. Conservation of wetlands: do infertile wetlands deserve a higher priority? Biol. Conserv.
Noy-Meir I. & van der Maarel E. 1987. Relations between community theory and community analysis in vegetation science: some historical perspectives. Vegetatio 69: 5–15.
Pielou E. C. 1979. On A. J. Underwood's model for a random pattern. Oecol. 44: 143–144.
Pielou E. C. & Routledge R. D. 1976. Salt marsh vegetation: latitudinal variation in the zonation patterns. Oecol. 24: 311–321.
Shipley B. & Keddy P. A. 1987. The individualistic and community-unit concepts as falsifiable hypotheses. Vegetatio 69: 47–55.
Tilman D. 1982. Resource competition and community structure. Princeton University Press, Princeton.
Tilman D. 1987. The importance of the mechanisms of interspecific competition. Am. Nat. 126: 769–774.
Vermeer J. G. & Berendse F. 1983. The relationship between nutrient availability, shoot biomass and species richness in grassland and wetland communities. Vegetatio 53: 121–126.
Vermeer J. G. & Verhoeven J. T. A. 1987. Species composition and biomass production of mesotrophic fens in relation to the nutrient status of the organic soil. Oecol. Plant. 8: 321–330.
Walker J. & Peet R. K. 1983. Composition and species diversity of pine-wiregrass savannas of the Green Swamp, North Carolina. Vegetatio 55: 121–126.
Wheeler B. D. & Giller K. E. 1982. Species richness of herbaceous fen vegetation in Broadland, Norfolk in relation to the quantity of above-ground plant material. J. Ecol. 70: 179–200.
Willems J. H. 1980. Observations on north-west European limestone grassland communities. An experimental approach to the study of species diversity and above-ground biomass in chalk grassland. Proc. K. Ned. Akad. Wet. Series C. 83: 279–306.
Wilson S. D. & Keddy P. A. 1985. Plant zonation on a shoreline gradient: physiological response curves of component species. J. Ecol. 73: 851–860.
Wilson S. D. & Keddy P. A. 1986. Measuring diffuse competition along an environmental gradient: results from a shoreline plant community. Am. Nat. 127: 862–869.
Wisheu, I. C. & Keddy, P. A. in press. The conservation and management of a threatened coastal plain plant community in Eastern North America (Nova Scotia, Canada). Biol. Conserv.
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Moore, D.R.J., Keddy, P.A. The relationship between species richness and standing crop in wetlands: the importance of scale. Vegetatio 79, 99–106 (1988). https://doi.org/10.1007/BF00044853
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DOI: https://doi.org/10.1007/BF00044853