Functional trait sorting increases over succession in metacommunity mosaics of fish assemblages.

Metacommunity theory predicts that the relative importance of regional and local processes structuring communities will change over time since initiation of community assembly. Determining effects of these processes on species and trait diversity over succession remains largely unaddressed in metacommunity ecology to date, yet could confer an improved mechanistic understanding of community assembly. To test theoretical predictions of the increasing importance of local processes in structuring communities over successional stages in metacommunities, we evaluated fish species and trait diversity in three pond metacommunities undergoing secondary succession from beaver (Castor canadensis) disturbance.

Native species dispersal reduces community invasibility by increasing species richness and biotic resistance.

Recent studies indicate that diversity-invasibility relationships can depend on spatial scale, but the contributing role of native species dispersal among local communities in mediating these relationships remains unaddressed. Metacommunity ecology highlights the effects of species dispersal rates on local diversity, thereby suggesting that native species dispersal may influence local biotic resistance to invasion by non-native species. However, the effects of native species dispersal rates on local native diversity and invasibility could depend on any intraspecific differences of the invader that may alter establishment success.

Emergence of a novel prey life history promotes contemporary sympatric diversification in a top predator.

Intraspecific phenotypic variation can strongly impact community and ecosystem dynamics. Effects of intraspecific variation in keystone species have been shown to propagate down through the food web by altering the adaptive landscape for other species and creating a cascade of ecological and evolutionary change. However, similar bottom-up eco-evolutionary effects are poorly described.

Intraspecific phenotypic variation among alewife populations drives parallel phenotypic shifts in bluegill.

Evolutionary diversification within consumer species may generate selection on local ecological communities, affecting prey community structure. However, the extent to which this niche construction can propagate across food webs and shape trait variation in competing species is unknown. Here, we tested whether niche construction by different life-history variants of the planktivorous fish alewife (Alosa pseudoharengus) can drive phenotypic divergence and resource use in the competing species bluegill (Lepomis macrochirus).

Intraspecific phenotypic variation in a fish predator affects multitrophic lake metacommunity structure.

Contemporary insights from evolutionary ecology suggest that population divergence in ecologically important traits within predators can generate diversifying ecological selection on local community structure. Many studies acknowledging these effects of intraspecific variation assume that local populations are situated in communities that are unconnected to similar communities within a shared region. Recent work from metacommunity ecology suggests that species dispersal among communities can also influence species diversity and composition but can depend upon the relative importance of the local environment.

Predation inhibits the positive effect of dispersal on intraspecific and interspecific synchrony in pond metacommunities.

Recent interest in the ecological drivers of compensatory and synchronous population dynamics has provided an improved yet incomplete understanding of local and regional population oscillations in response to variable environments. Here, we evaluate the effect of dispersal rate and spatiotemporal heterogeneity in predation by the selective planktivore, bluegill sunfish (Lepomis macrochirus), on local and regional dynamics of zooplankton in pond metacommunities. A metacommunity consisted of three pond mesocosm communities, one with constant presence of predators, one without predators, and one with alternating presence-absence of predators.

Species dispersal rates alter diversity and ecosystem stability in pond metacommunities.

Metacommunity theory suggests that relationships between diversity and ecosystem stability can be determined by the rate of species dispersal among local communities. The predicted relationships, however, may depend upon the relative strength of local environmental processes and disturbance. Here we evaluate the role of dispersal frequency and local predation perturbations in affecting patterns of diversity and stability in pond plankton metacommunities.

Prey dispersal rate affects prey species composition and trait diversity in response to multiple predators in metacommunities.

1. Recent studies indicate that large-scale spatial processes can alter local community structuring mechanisms to determine local and regional assemblages of predators and their prey. In metacommunities, this may occur when the functional diversity represented in the regional predator species pool interacts with the rate of prey dispersal among local communities to affect prey species diversity and trait composition at multiple scales.

Contrasting demographic and genetic estimates of dispersal in the endangered Coahuilan box turtle: a contemporary approach to conservation.

The evolutionary viability of an endangered species depends upon gene flow among subpopulations and the degree of habitat patch connectivity. Contrasting population connectivity over ecological and evolutionary timescales may provide novel insight into what maintains genetic diversity within threatened species. We employed this integrative approach to evaluating dispersal in the critically endangered Coahuilan box turtle (Terrapene coahuila) that inhabits isolated wetlands in the desert-spring ecosystem of Cuatro Ciénegas, Mexico.

Planktonic dispersal dampens temporal trophic cascades in pond metacommunities.

Trophic cascades, in which changes in predation affect the biomass of lower trophic levels, vary substantially in strength and incidence. Most work to explain this variation has focused on local factors and has ignored larger regional effects. To study how metacommunity dynamics can alter trophic cascades, we constructed mesocosm metacommunities consisting of three pond communities with heterogeneous levels of fish predation and examined how planktonic dispersal rate (5-140% per week) affected biomass partitioning.