The geometry of coexistence

Abstract

Understanding the processes that maintain diversity has been the focus of extensive study, yet there is much that has not been integrated into a cohesive framework. First, there is a separation of perspective. Ecological and evolutionary approaches to diversity have progressed in largely parallel directions. Second, there is a separation of emphasis. In both ecology and population genetics, classical theories fairour local explanations with emphasis on population dynamics and selection n'ithin populations, while contemporary theories favour spatial explanations, with emphasis on population structure and interactions amung populations. What is lacking is a comparative approach that evaluates the relative importance of local and spatial processes in maintaining genetic and ecological diversity. I present a framework for diversity maintenance that emphasizes the comparative approach. I use a well-known but little-used mathematical approach, the perturbation theorem for dynamical systems, to identify key points ofcontact between ecological and population genetic theories ofcoexistence. These connections provide for a synthesis of several important concepts: population structure (source-sink versus extinction-colonization), spatial heterogeneity (intrinsic versus extrinsic) in fitness and competitive ability, and temporal scales over which local and spatial processes influence diversity. This framework ties together a large and diverse body of theory and data from ecolo<gy and population genetics. It yields comparative predictions that can serve as ,guidelines in biodiversity management.

Island Biogeography of Genes and Species

“…of departure, study of the SGDC focuses attention on the points of contact between the processes that influence both levels of diversity (see also Amarasekare 2000) and calls for a cross-disciplinary approach to biodiversity research. Unified models that address both levels of diversity simultaneously are now needed to understand the factors that drive variation among systems in the strength of the SGDC.…”

“…However, despite important advances in other areas of evolutionary and conservation biology that have resulted from integration of ecological and genetic perspectives (e.g., Real 1994;Young and Clarke 2000), these two levels of diversity have traditionally remained the exclusive domains of community ecology and population genetics, respectively. A number of authors have noted strong parallels between the processes and concepts underlying theories of species diversity and genetic diversity (e.g., Harper 1977;Antonovics 1978;Huston 1994;Amarasekare 2000;Hubbell 2001), but the question of whether parallel process has led to parallel pattern has yet to be explored in a rigorous way. If there is generally a positive correlation between species diversity and genetic diversity, then the parallels between ecological and genetic theories not only may be of heuristic value but also may point to the potential for theories of biodiversity to be unified across organizational levels.…”

Deciphering the drivers of negative species–genetic diversity correlation in Alpine amphibians

“…Although connections between population genetics and community ecology have long been recognized (e.g., Amarasekare, 2000;Antonovics, 2003;Bell, 2001;Hubbell, 2001), only in the last decades have attempts been made to elucidate the relationships between these two levels of biodiversity. Vellend (2003) proposed a general theoretical framework for the correlation between species and genetic diversity (SGDC), and since then, multiple studies have explicitly tested SGDCs in plant and animal communities (reviewed by: Lamy, Laroche, David, Massol, & Jarne, 2017;Vellend, 2003;Vellend & Geber, 2005;Vellend et al, 2014).…”

Species Diversity and Genetic Diversity: Parallel Processes and Correlated Patterns

“…199-215. ᭧ 2005 1972; Antonovics 1976Antonovics , 1992Antonovics , 2003Harper 1977;Van Valen 1982;Huston 1994;Hairston et al 1996;Amarasekare 2000;Jain 2000;Bell 2001;Kassen 2002;Chave 2004). Although population genetics and community ecology share almost nothing in the way of history, they share a virtually identical interest in explaining the numbers and relative frequencies of biological variants found in nature.…”

“…In population genetics, these variants are genotypes or alleles, while in community ecology they are usually species. The strength of these conceptual parallels is illustrated by considering the observation that a haploid genotype is functionally identical to a species, at least from a theoretical viewpoint (e.g., Antonovics 1976;Amarasekare 2000). Since most of the basic tenets of theoretical population genetics hold equally for haploids and diploids (Lewontin 1974;Bell 1997), many population-genetics models can be applied with equal validity to the species composition of a community and to the genetic composition of a population.…”