PARENT SESSION
Contributed Oral Session 5: Aquatic Ecology: System Heterogeneity
Monday, August 8, 8:00 AM - 11:30 AM, Meeting Room 515 A, Level 5, Palais des congrès de Montréal

Population dynamic consequences of spatial heterogeneity in animals with complex life histories.

Ellis, Alicia^*,1, McPeek, Mark¹, ¹ Dartmouth College, Hanover, NH, USA

ABSTRACT- While many scientific investigations in population ecology initially make simplifying assumptions about the nature of population dynamics (e.g., no immigration or emigration, no age or stage structure, environmental homogeneity), many, if not most, organisms have complex life histories where adult and juvenile life stages live in two distinct habitats and the landscape in which a population inhabits is heterogeneous at multiple spatial and temporal scales. Thus, to fully understand and predict the distribution and abundance of organisms in nature, it is necessary to understand how spatial heterogeneity at multiple spatial scales influences the demographics of different life stages and the population dynamic consequences of this variability in natural populations. Mosquitoes that inhabit water-filled tree holes provide a unique opportunity to examine how spatial heterogeneity at multiple scales influences the population demographics of different life stages. Like many insects, mosquitoes have a terrestrial adult stage and an aquatic larval stage and experience heterogeneity at two distinct spatial scales. The purpose of this study was to examine how the demographics of larval and adult stages are simultaneously influenced by variability in the tree hole and forest habitats. The first part of this investigation examined the pattern of larval abundance at two spatial scales, the tree hole scale and the forest patch scale, and two temporal scales, within and between years. Results indicated that larval abundance was significantly higher in deciduous forests than in evergreen forests and open fields. The second and third studies in this investigation were designed to test two possible mechanisms generating the observed pattern of larval abundance: differences in oviposition activity among habitats, and habitat specific differences in fitness. Results from these studies suggest that habitat selective behaviors of adults may be responsible for generating the observed pattern of larval abundance. Broadly, this study demonstrates that for some organisms, different life history stages experience different environmental constraints on vastly different spatiotemporal scales and that these differences can have important implications for population dynamics and patterns of distribution and abundance.

Key words: scale, mosquito, life history, heterogeneity