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Grantee Research Project Results

NCER Grantee Research Project Results

The Ecological and Evolutionary Impacts of Predation and Density on Life-History and Population Demography of a Model Fish Species

EPA Grant Number: F5E11165
Title: The Ecological and Evolutionary Impacts of Predation and Density on Life-History and Population Demography of a Model Fish Species
Investigators: Kindsvater, Holly K.
Institution: University of Florida
EPA Project Officer: Cobbs-Green, Gladys M.
Project Period: August 1, 2004 through August 1, 2009
Project Amount: $108,000
RFA: STAR Graduate Fellowships (2005)
Research Category: Academic Fellowships

Description:

Objective:

Individual life-history traits and population demography and density are fundamentally linked, but historically have been studied in isolation. Selection pressure from predation acts on individual trade-offs between life-history characters (growth, reproductive effort, and fecundity) and thus has indirect consequences for population size structure. This project will investigate how size-specific mortality risk and density-dependent processes mediate the allocation of resources to growth and reproduction in fish and link them to population demography.

My study will focus on how differential mortality from different predator suites and population density alter individual reproductive traits of the least killifish, Heterandria formosa. Ultimately understanding the processes that determine life-history trade-offs in this model species will provide more general understanding of the evolutionary consequences of size-specific predation pressure on population demography.

The importance of understanding the evolutionary role of ecological processes, such as predation and density, in shaping population structure is recognized but rarely studied in fish populations. Such knowledge will contribute to more effective management and conservation of fish populations. This project examines how the evolutionary response to predation and density changes how individuals balance the energetic demands of growing and reproducing, which in turn affects population demography. My approach uses field and laboratory experiments and theoretical tools to examine individual reproduction and population demography of a model fish species, Heterandria formosa.

Approach:

I will examine how differences in reproductive traits correlate with different predator communities, and with differences in population demography in wild populations of H. formosa. I will conduct selection experiments conducted in mesocosm populations in order to determine the relative importance of different selection pressures in the wild. Additionally I will build a dynamic optimization model to make specific theoretical predictions. The theoretical component of the work will allow me to make general predictions about the evolutionary roles of predation and density in determining population size structure.

Expected Results:

I expect differences in life-history to correlate with differences in population size-structure in my observations of wild populations and in my experimental mesocosm populations. I expect to gain new understanding of the factors governing the allocation of energy to growth and reproduction in female fish, providing more sophisticated knowledge of life-history evolution.

Supplemental Keywords:

life-history trade-offs, reproductive allocation, Heterandria formosa, least killifish, model species, predation, density-dependence,, Scientific Discipline, Ecosystem Protection/Environmental Exposure & Risk, Habitat, Environmental Monitoring, Ecology and Ecosystems, habitat dynamics, fish, habitat use, population demography, animal responses, mortality, predation, breeding habitat

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The perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Conclusions drawn by the principal investigators have not been reviewed by the Agency.

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