Competitive Coexistence (competitive + coexistence)

Distribution by Scientific Domains


Selected Abstracts


Competitive coexistence in spatially structured environments: a synthesis

ECOLOGY LETTERS, Issue 12 2003
Priyanga Amarasekare
Abstract Theoretical developments in spatial competitive coexistence are far in advance of empirical investigations. A framework that makes comparative predictions for alternative hypotheses is a crucial element in narrowing this gap. This review attempts to synthesize spatial competition theory into such a framework, with the goal of motivating empirical investigations that adopt the comparative approach. The synthesis presented is based on a major axis, coexistence in spatially homogeneous vs. heterogeneous competitive environments, along which the theory can be organized. The resulting framework integrates such key concepts as niche theory, spatial heterogeneity and spatial scale(s) of coexistence. It yields comparative predictions that can guide empirical investigations. [source]


Park's Tribolium competition experiments: a non-equilibrium species coexistence hypothesis

JOURNAL OF ANIMAL ECOLOGY, Issue 5 2003
Jeffrey Edmunds
Summary 1In this journal 35 years ago, P. H. Leslie, T. Park and D. B. Mertz reported competitive exclusion data for two Tribolium species. It is less well-known that they also reported ,difficult to interpret' coexistence data. We suggest that the species exclusion and the species coexistence are consequences of a stable coexistence two-cycle in the presence of two stable competitive exclusion equilibria. 2A stage-structured insect population model for two interacting species forecasts that as interspecific interaction is increased there occurs a sequence of dynamic changes (bifurcations) in which the classic Lotka,Volterra-type scenario with two stable competitive exclusion equilibria is altered abruptly to a novel scenario with three locally stable entities; namely, two competitive exclusion equilibria and a stable coexistence cycle. This scenario is novel in that it predicts the competitive coexistence of two nearly identical species on a single limiting resource and does so under circumstances of increased interspecific competition. This prediction is in contradiction to classical tenets of competition theory. [source]


Dynamics of regional coexistence for more or less equal competitors

JOURNAL OF ANIMAL ECOLOGY, Issue 1 2003
C. Patrick Doncaster
Summary 1Competition between two species in a metapopulation involves each inhibiting the other's ability firstly to colonize an already occupied area and then to persist in it. Models for regional competition of this kind have 3-D dynamics, from which it has proved difficult to extract useful predictions except for special conditions. We introduce a 2-D general model for species that are equally vigorous at inhibiting the ability of others to remain in an occupied patch as to arrive there. The model covers the full spectrum of competitive interactions, from weak to strong and symmetrical to asymmetrical. Its Lotka,Volterra dynamics extend the general theory of competitive coexistence by generating clear predictions for community structure, amenable to cross-system comparisons and experimental manipulations. 2Previous 2-D models of interactions between dominant and fugitive species are special cases of the 2-D general model. Moderately asymmetrical competition has two outcomes distinctly different from dominant,fugitive interactions, at both the scale of metapopulation and population: (i) slow growing and weak competitors coexist with faster growing superior competitors, albeit at reduced densities; and (b) habitat removal always yields relative gains in abundance for species with higher growth capacity, but the gains are absolute only for species subjected to competitive impacts that exceed within-species impacts. Extinctions of slow growing and weak competitors provide the most sensitive indication of habitat degradation, and their losses also have the least effect on community structure. 3The 2-D general model further predicts that highly productive communities will tolerate differences between species in their capacity for population growth, whereas less productive communities will tolerate stronger competitive interactions between species. This prediction applies equally to a population of resource consumers as to a metapopulation of colonists. The model explicitly links local and regional population dynamics to r,K selection in community structure by predicting a prevalence of growth-orientated species in resource-poor habitats and competition-orientated species in resource-rich habitats. [source]