Title

Population response to spatial heterogeneity: Hemilepistus reaumuri as a case study

Date of Completion

January 2004

Keywords

Biology, Ecology

Degree

Ph.D.

Abstract

Spatial heterogeneity is seen as an important factor in many ecological systems. The kind and degree of heterogeneity in a system is highly dependent on the spatial scale at which it is analyzed. Accounting for the spatial structure of heterogeneity in field studies is essential for estimating the importance of various ecological processes. My dissertation focuses on a simple organism, the terrestrial isopod Hemilepistus reaumuri, in a simple system, the Negev desert of Israel, to elucidate the measurement and analysis of spatial heterogeneity and its impact on population dynamics. I will begin with a preliminary analysis of the pattern of isopod settlement. Then I will focus on measuring dispersal behavior at multiple spatial and organization scales. Explicit rules for scaling between the different levels will be presented. Finally, I will cover approaches to measuring and modeling spatial pattern. Along with data on the isopod, appropriate case studies will be used to illustrate specific ideas. I show the possibilities of moving beyond just characterizing spatial pattern to modeling the interaction of individuals and their environment. For the isopods, we found a strong response to amount of shrub, rock, and dew availability with regards to site selection. Given that water is the limiting factor in the Negev and that these factors control water availability, our results help to show how heterogeneity controlling limiting resources producing clear and consistent signals. ^