A surprising Poisson process arising from a species competition model

Motivated by the work of Tilman (Ecology 75 (1994) 2) and May and Nowak (J. Theoret. Biol. 170 (1994) 95) we consider a process in which points are inserted randomly into the unit interval and a new point kills each point to its left independently and with probability a. Intuitively this dynamic will create a negative dependence between the number of points in adjacent intervals. However, we show that the ensemble of points converges to a Poisson process with intensity 1=(a(1− x)), and the number of points at time t grows like (log t)=a. c © 2002 Elsevier Science B.V. All rights reserved.