Community Ecology - Texas Tech University



Community Ecology

Species/area relationship

 

Outline:

1. Discussion of the ubiquitous relationship between species richness and area

A. Patterns associated with k and z

2. Some possible explanations for this pattern

3. How loss of A may unexpectedly affect S via supersaturation

4. How universal is the S/A relationship?

 

 

As area increases, richness increases: one of the few “laws” in ecology, according to Schoener (1976)

First attributed to H.C. Watson (1859)

 

Lots of empirical evidence for S/A relationship -

e.g. Darlington’s Rule

 

Formalization of the S/A relationship - Arrhenius 1921, Preston 1962:

S = kAz

where k = y-intercept, z = slope, S=number of species, A=area

To linearize: log(S) = zlog(A) + log (k)

This power-law equation is only one kind of S/A relationship. See Scheiner (2003) for a discussion of other types of species-area curves, based on various aspects of sampling.

Properties of k and z can provide insights about isolation, extinction risk, etc.:

k –

z –

In general, data are plotted and a curve is then fitted retroactively, which allows calculation of k and z.

 

Explanations for species-area relationship:

1) area per se with respect to colonization and extinction

2) habitat heterogeneity hypothesis

3) passive sampling phenomenon

 

BUT...

1. The S/A pattern is based on species presence alone, and thus ignores abundance differences and includes transients.

2. Over what time period should S be tallied?

3. How should A be measured (e.g. effects of topography/surface area)?

4. There are exceptions:

Habitat loss, supersaturation, faunal relaxation, extinction debt:

 

So what are we to conclude about species/area relationships? S is related to A because of a variety of factors that vary with A, including habitat, sampling, and other properties. There is considerable scatter about the S/A regression line (supersaturation). Nonetheless, the S/A relationship is a reasonably robust pattern––it is the process behind it that is unclear.

Next time: the relationship between biodiversity and environmental productivity.

 

References:

 

Abbott, I. 1983. The meaning of z in species/area regressions and the study of species turnover in island biogeography. Oikos 41:385-390.

 

Arrhenius, O. 1921. Species and area. J. Ecol. 9:95-99.

 

Becker, P. 1992. Colonization of islands by carnivorous and herbivorous Heteroptera and Coleoptera: effects of island area, plant species richness, and ‘extinction’ rates. J. Biogeogr. 19:163-171.

 

Boecklen, W.J. 1986. Effects of habitat heterogeneity on the species-area relationships of forest birds. J. Biogeogr. 13:59-68.

 

Connor, E.F., and E.D. McCoy. 1979. The statistics and biology of the species-area relationship. Am. Nat. 113:791-833.

 

Darlington, P.J. 1957. Zoogeography: The Geographical Distribution of Animals. Wiley, New York, NY.

 

den Boer, P.J. 1968. Spreading of risk and stabilization of animal numbers. Acta Biotheor. 18:165- 194.

 

Diamond, J.M. 1972. Biogeographic kinetics: estimation of relaxation times for avifaunas of southwest Pacific islands. Proc. Nat. Acad. Sci. USA 69:3199-3203.

Drakare, S., J.J. Lennon, and H. Hillebrand. 2006. The imprint of the geographical, evolutionary and ecological context on species-area relationships. Ecology Letters 9:215-227.

 

Kalmar, A., and D.J. Currie. 2006. A global model of island biogeography. Global Ecol. Biogeogr. 15:72-81.

Kalmar, A., and D.J. Currie. 2007. A unified model of avian species richness on islands and continents. Ecology 88:1309-1321.

Preston, F.W. 1948. The commonness and rarity of species. Ecology 29:254-283.

 

Preston, F.W. 1962. The canonical distribution of commonness and rarity of species. Ecology 43:185-215.

Rosenzweig, M.L. 1995. Species Diversity in Space and Time. Cambridge Univ. Press, New York, NY.

 

Scheiner, S.M. 2003. Six types of species-area curves. Global Ecology & Biogeography 12:441-447.

Schoener, T.W. 1976. The species-area relationship within archipelagos: models and evidence from island land birds. Proceedings of the 16th International Ornithological Congress (Canberra), pp. 629- 642.

 

Sugihara, G. 1981. S=CAz, z=¼: a reply to Connor and McCoy. Am. Nat. 117:790-793.

 

Tilman, D., R.M. May, C.L. Lehman, and M.A. Nowak. 1994. Habitat destruction and the extinction debt. Nature 371:65-66.

Whittaker, R.J., and J.M. Fernández-Palacios. 2007. Island Biogeography: Ecology, Evolution, and Conservation (2nd ed.). Oxford Univ. Press, Oxford.

 

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