Models of Multiple Dispersers from the Nest: Predictions and Inference

• Published in: Ecology (Durham) 1991-10, Vol.72 (5), p.1721-1730
• Main Authors: Tonkyn, David W., Plissner, Jonathan H.
• Format: Article
• Language: English
• Subjects: Animal and plant ecology; Animal behavior; Animal ecology; Animal, plant and microbial ecology; Animals; Biological and medical sciences; Ecological competition; Ecological genetics; Ecological modeling; Fundamental and applied biological sciences. Psychology; Inbreeding; Modeling; Population ecology; Search strategies; Siblings; Vertebrata
• ISSN: 0012-9658; 1939-9170
• DOI: 10.2307/1940971

Many vertebrate populations exhibit large variation in natal dispersal distances. Murray (1967) showed by simulation that this variation need not have a genetic basis, but could result from two factors, chance variation in proximity to suitable sites, and competition with sibs and neighbors for those sites. Waser (1985) developed an analytic model of the first of these effects, which predicts the probability that an individual will locate an available site within any given distance, under two limiting search strategies. We extend the model to consider the distances traveled by multiple dispersers from a site, under both search strategies, and show that competitive exclusion by early dispersers can further increase the variation in dispersal distances. The incorporates the effects of competition with siblings, but not with dispersers from other natal sites, and brings us part way toward an analytic solution to Murray's original model. In addition, we discuss both the difficulties inherent in testing models of dispersal, and the importance of doing so for the understanding of various behavioral, population, and evolutionary processes.