Dispersal of annual plants in hierarchically structured landscapes

Abstract

The scale at which plants utilize spatially distributed resources may be determined by their ability to locate sites that can sustain population growth. We developed a spatially-explicit model of the dispersal of annual plants in landscapes which were hierarchically structured, i.e., the spatial pattern of suitable sites was nested and scale-dependent. Results show that colonizing ability and extinction probability are most sensitive to the mean dispersal distance of the species. Dispersal out of the parental site, but within the immediate neighborhood, was the most efficient means for popolation expansion. When landscape patterns change with scale then dispersal distances determine the spatial scales of habitat utilization. As a complicating factor, the type of statistical distribution of dispersal distances also influences the colonizing ability. However, the importance of dispersal distance mean and distribution decreased as the number and connectance of suitable sites increased. The results suggest that landscape models which consider the interaction between scale dependent changes in landscape pattern and species dispersal and establishment characteristics are relevant to many issues in community ecology, invasion biology, and conservation biology.

Dispersal and Metapopulation Viability in a Heterogeneous Landscape

“…Variations in sites quality and distribution and shapes of sites are the main elements that are assumed to contribute to landscape heterogeneity (Wiens, 1997). The e!ects of sites pattern have been investigated in previous models (Hanski & Gyllenberg, 1993;Adler & Nuernberger, 1994;Wu & Levin, 1994;Lavorel et al, 1995;Holt, 1997). The in#uence of the quality of sites themselves can be taken into account using the spatially implicit representation of an elementary landscape.…”

Tools for Conserving Managing Individual Plant Species in Dynamic Landscapes

“…Lavorel et al 1995;Collingham & Huntley 2000;Russo 2005;Schurr et al 2005). Alternative, 'fat-tailed' distributions predict plant dispersal much closer to observed patterns.…”

Spatio-temporal patterns of colonization and expansion of Retama monosperma on developing coastal dunes

“…The presence of dispersers is an essential factor for the spread of R. monosperma in this fragmented landscape, as the seeds of the shrub have no other means of dispersal, and the only way of spreading unassisted is by a slow diffusion process from an R. monosperma clump, which eventually leads to full ridge occupation (Lavorel et al 1995). However, in a fragmented landscape, where potentially suitable habitat is patchily distributed (surrounded by tidal swales), only long-distance dispersal (LDD) can contribute to the colonization and expansion of R. monosperma (Cain et al 2000;Nathan et al 2003).…”