Alexander S. Flecker

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Michael J. Vanni,* Alexander S. Flecker, James M. Hood and Jenifer L. Headworth Department of Zoology, Miami University, Oxford, OH 45056, USA Department of Ecology and Evolutionary Biology, Cornell University, Ithaca, NY 14853, USA. *Correspondence: E-mail: vannimj@muohio.edu Present address: Department of Ecology, Evolution and Behavior, University of(More)
Theory suggests evolutionary change can significantly influence and act in tandem with ecological forces via ecological-evolutionary feedbacks. This theory assumes that significant evolutionary change occurs over ecologically relevant timescales and that phenotypes have differential effects on the environment. Here we test the hypothesis that local(More)
Ecosystem engineering – the physical modification of habitats by organisms – has been proposed as an important mechanism for maintaining high species richness at the landscape scale by increasing habitat heterogeneity. Dams built by beaver (Castor canadensis) dramatically alter riparian landscapes throughout much of North America. In the central(More)
Rates of biogeochemical processes often vary widely in space and time, and characterizing this variation is critical for understanding ecosystem functioning. In streams, spatial hotspots of nutrient transformations are generally attributed to physical and microbial processes. Here we examine the potential for heterogeneous distributions of fish to generate(More)
Ecologists have long been interested in understanding the strengths of consumer and resource limitation in influencing communities. Here we ask three questions concerning the relative importance of nutrients and grazing fishes to primary producers of a tropical Andean stream: (1) Are stream algae nutrient limited? (2) Are top-down and bottom-up forces of(More)
An experiment was conducted to evaluate the interaction between predation, substrate, and spatial refugia in the organization of a stream insect community (Reeds Creek, Pendleton Co., West Virginia). Patterns of insect colonization were compared between fish exclusion cages and open controls that allowed access to vertebrate predators. Each cage contained 4(More)
The decomposition of plant litter is one of the most important ecosystem processes in the biosphere and is particularly sensitive to climate warming. Aquatic ecosystems are well suited to studying warming effects on decomposition because the otherwise confounding influence of moisture is constant. By using a latitudinal temperature gradient in an(More)
There is increasing evidence that species extinctions jeopardize the functioning of ecosystems. Overfishing and other human influences are reducing the diversity and abundance of fish worldwide, but the ecosystem-level consequences of these changes have not been assessed quantitatively. Recycling of nutrients is one important ecosystem process that is(More)
Stable isotopes are widely used as time-integrating tracers of trophic interactions, but turnover rates of isotopes in animal tissues remain poorly understood. Here, we report nitrogen (N) isotope turnover rates in tissues of four primary consumer species: Ancistrus triradiatus armored catfish (muscle, fins, and whole blood), Tarebia granifera snails(More)
Diverse microbial consortia profoundly influence animal biology, necessitating an understanding of microbiome variation in studies of animal adaptation. Yet, little is known about such variability among fish, in spite of their importance in aquatic ecosystems. The Trinidadian guppy, Poecilia reticulata, is an intriguing candidate to test microbiome-related(More)