PARENT SESSION
Poster Session: Qualitative Relationships Between Landscape Processes and Patterns

Importance of movement varies in static and dynamic landscapes. ^*NAGY, LAURA R. and SCHUMAKER, NATHAN , ¹ U.S. Environmental Protection Agency, Corvallis, OR , USA

ABSTRACT- The relative sensitivity of spatially explicit population models (SEPMs) to movement parameters is a topic of ongoing debate among theoretical ecologists. In this study, we add additional realism to this debate by examining a SEPM's sensitivity to dispersal ability in static vs. dynamic landscapes, and in the presence or absence of environmental stochasticity. We hypothesized that individuals should be forced to relocate more frequently in a dynamic landscape because they will be displaced when high quality areas are lost. Thus the additional need to relocate should make a SEPM more sensitive to movement parameters in a dynamic landscape. To test this prediction, we used a spatially-explicit, individually-based model (PATCH) to evaluate the relationship between population size and movement distance in both static and dynamic landscapes. We modeled a population of vesper sparrows residing in a hypothetical agricultural landscape that was either static or subject to continual habitat change. In the dynamic landscape, the arrangement of crops was altered every 10 years. In contrast to our prediction, we found movement ability had a greater effect in static landscapes. Our results show that that the sensitivity of models to uncertainty in movement parameters vary as a function of how realistically models treat the stochasticity of the landscape.

KEY WORDS: dispersal, PATCH, movement, dynamic