Uniting Two General Patterns in the Distribution of Species
Two patterns in the distribution of species have become firmly but independently established in ecology: the species-area curve, which describes how rapidly the number of species increases with area, and the positive relation between species' geographical distribution and average local abundance. There is no generally agreed explanation of either pattern, but for both the two main hypotheses are essentially the same: divergence of species along the ecological specialist-generalist continuum and colonization- extinction dynamics. A model is described that merges the two mechanisms, predicts both patterns, and thereby shows how the two general, but formerly disconnected, patterns are interrelated.
Hanski
I
I. Hanski, Department of Ecology and Systematics, University of Helsinki, Post Office Box 17, FIN-00014 Helsinki, Finland. M. Gyllenberg, Department of Mathematics, University of Turku, FIN-20014 Turku, Finland.
Gyllenberg
M