Bathing birds bias beta-diversity: frequent dispersal by gulls homogenizes fauna in a rock-pool metacommunity.

Metacommunity theory generally predicts that regional dispersal of organisms among local habitat patches should influence spatial patterns of species diversity. In particular, increased dispersal rates are generally expected to increase local (alpha) diversity, yet homogenize local communities across the region (decreasing beta-diversity), resulting in no change in regional (gamma) diversity. Although the effect of dispersal on alpha-diversity has garnered much experimental attention, the influence of dispersal rates on diversity at larger spatial scales (beta and gamma) is poorly understood.

Aquatic bacterial assemblage variability in the supra littoral zone of Appledore Island, Gulf of Maine.

We investigated the abundance and assemblage variability of bacteria in 10 spatially distinct freshwater pools on Appledore Island, Gulf of Maine. Assemblages were strongly heterogeneous between pools separated by even short distances. To gain insight into factors that may lead to the establishment of novel assemblages, we conducted an ecosystem-open choromophoric dissolved organic matter (CDOM) enrichment experiment within mesocosms inoculated with a standardized microbial community and observed patterns of their composition over time.

Resource ecology of virulence in a planktonic host-parasite system: an explanation using dynamic energy budgets.

Parasites steal resources that a host would otherwise direct toward its own growth and reproduction. We use this fundamental notion to explain resource-dependent virulence in a fungal parasite (Metschnikowia)-zooplankton host (Daphnia) system and in a variety of other disease systems with invertebrate hosts. In an experiment, well-fed hosts died faster and produced more parasites than did austerely fed ones.

Friendly competition: evidence for a dilution effect among competitors in a planktonic host-parasite system.

The "dilution effect" concept in disease ecology offers the intriguing possibility that clever manipulation of less competent hosts could reduce disease prevalence in populations of more competent hosts. The basic concept is straightforward: host species vary in suitability (competence) for parasites, and disease transmission decreases when there are more incompetent hosts interacting with vectors or removing free-living stages of a parasite. However, host species also often interact with each other in other ecological ways, e.