Effect of Food Availability and Predation on the Population Dynamics and Spacing Behavior of Prairie Voles

Microtine rodent (lemmings and voles) populations often undergo seasonal or multi-annual fluctuations in density. Although a number of single factors have been proposed as the causal agent of these fluctuations, no one has demonstrated convincingly that a single-factor mechanism is responsible. Recent studies indicate that three factors, nutrition, predation, and spacing behavior, may act jointly to influence fluctuations in microtine populations. Field studies of microtine populations in which two or more extrinsic factors were experimentally manipulated simultaneously are few. Furthermore, none used a factorial design with replicates to determine individual and interactive effects. In this study, I manipulated food availability and predation and used a factorial design with replicates. I tested the hypothesis that food availability, predation, and spacing behavior interact to limit densities of prairie voles. My results show that supplemental, high-quality food significantly affected density, recruitment, reproductive activity, and body growth rates of voles. In addition, voles in food-supplemented populations were significantly less aggressive towards one another than voles in non-supplemented populations. Predation significantly affected density, recruitment, and on some occasions, adult survival. The only significant food-predator interaction was for body growth rates when presence of predators inhibited the growth response. In conclusion, I demonstrated that both predation and food operate simultaneously, and in an additive manner, to limit densities of prairie voles in east central Illinois. Such interactions should be expected and considerd when analyzing population dynamics of voles.

Name thesis:degree_name

Ph.D.

Level thesis:degree_level

Dissertation

Discipline thesis:degree_discipline

Ecology, Evolution, and Conservation Biology

Grantor

University of Illinois at Urbana-Champaign

Year dc:date

2015

Author dc:creator

• Desy, Elizabeth Anne

• Biology, Ecology

Language dc:language

eng

Identifier

(UMI)AAI8803016

OAI identifier oai:identifier

oai:www.ideals.illinois.edu:2142/77626