A Theory of Spatial Structure in Ecological Communities at Multiple Spatial Scales

Abstract

Abstract. A theory of spatial structure in ecological communities is presented and tested. At the core of the theory is a simple allocation rule for the assembly of species in space. The theory leads, with no adjustable parameters, to nonrandom statistical predictions for the spatial distribution of species at multiple spatial scales. The distributions are such that the abundance of a species at the largest measured scale uniquely determines the spatialabundance distribution of the individuals of that species at smaller spatial scales. The shape of the species-area relationship, the endemics-area relationship, a scale-dependent community-level spatial-abundance distribution, the species-abundance distribution at small spatial scales, an index of intraspecific aggregation, the range-area relationship, and the dependence of species turnover on interpatch distance and on patch size are also uniquely predicted as a function solely of the list of abundances of the species at the largest spatial scale. We show that the spatial structure of three spatially explicit vegetation census data sets (i.e., a 64-m 2 serpentine grassland plot, a 50-ha moist tropical forest plot, and a 9.68-ha dry tropical forest plot) are generally consistent with the predictions of the theory, despite the very simple statistical assumption upon which the theory is based, and the absence of adjustable parameters. However, deviations between predicted and observed distributions do arise for the species with the highest abundances; the pattern of those deviations indicates that the theory, which currently contains no explicit description of interaction mechanisms among individuals within species, could be improved with the incorporation of intraspecific density dependence.

Whole-community DNA barcoding reveals a spatio-temporal continuum of biodiversity at species and genetic levels

“…Existing theoretical models predicting fractal scaling properties of species distributions are based on purely statistical properties 12,21 and do not incorporate a mechanistic foundation. Yet, they are consistent with the assumption of stochastic dispersal, birth and death of demographically equivalent individuals of neutral community models 8 that have been shown to produce established species-level macroecological patterns 8,9 .…”

Predicting spatial similarity of freshwater fish biodiversity

“…This observation suggests that the model can account for biodiversity similarity in a wide array of ecosystems, without assuming neutrality across species (30)(31)(32). Some of the previous studies, where analytical results were obtained, are based on the neutral hypothesis (33,34), although it is not always necessary to get exact results on the spatial turnover of species (35,36). The analysis of this latter, however, hinged so far on the abundance of each species across a 2-dimensional landscape: This provides a detailed description of biodiversity similarity distribution in space.…”

Statistical mechanics of relative species abundance

“…Various models have been applied to ecosystem communities where species compete for niches on a trophic level [9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,27,28,29], but these models have left the more complex systems a mystery. Such systems occur on multiple trophic levels and include various types of interspecies interactions, such as prey-predator relationships, mutualism, competition, and detritus food chains.…”