On the random placement hypothesis

A traditional method of summarizing spatial distribution of species is the observed species-area curve. Often the observed species-area curve is surpr isingly close to the expected species-area curve under the hypothesis of ra ndom placement of individuals. This has been used as evidence supporting th e hypothesis. In this paper, we argue that using the observed species-area curve to test the general random placement hypothesis is highly inefficient . We present a testing method based on the classical chi (2) test for over- dispersion which is not only more efficient but also applicable to situatio ns where complete abundance information are unavailable. We also discuss th ree alternatives of the hypothesis. The focus of this paper is on these and other general issues relevant to communities of different types. No applic ations are included in this paper.