PARENT SESSION
Contributed Oral Session 43: Landscape Ecology
Tuesday, August 9, 8:00 AM - 11:30 AM, Meeting Room 518 A, Level 5, Palais des congrès de Montréal

Determining the interactions between an insect and its environment across spatial scales; from host plants to landscapes.

Talley, Theresa^*,1, ¹ Department of Environmental Science & Policy, Davis, CA, USA

ABSTRACT- Metapopulation frameworks are often used for studying patchily distributed populations. The role that the environment plays in metapopulation dynamics is also widely recognized as is evidenced by various source-sink and habitat quality studies. The metapopulation approach is useful because it requires consideration of entire networks of local patches, which occur over landscape scales. However, this approach does not require an examination of landscape-level relationships; the focus is still largely on within patch dynamics. Researchers often address landscape influence by studying small-scale interactions at multiple locations or examining the relationship between within patch populations and the land use or vegetation of the surrounding areas (landscape context). Another approach, which acknowledges the environmental connectivity (spatial relationships) between patches, is to determine the spatial extent of species-environment interactions (e.g., by averaging variables across scales or comparing spatial patterns of variables). Determining the spatial extent of interactions discloses the factors acting on within-patch dynamics (extinction, abundance) and reveals whether these same factors may influence between-patch dynamics (i.e., movement, colonization). In the case of a rare riparian beetle in the Central Valley of California, occupancy of a particular host shrub was correlated with several variables representing host plant size and the presence of an exotic tree, traditionally considered a within-patch traits, as well as landscape-associated variables of proximity to the river and the width of the riparian corridor where the shrub occurred. However, a comparison of spatial distributions of the beetle and environmental variables along 20 km of river revealed a strong correspondence only to host plant distributions. These results suggest that landscape properties may mostly affect within-patch dynamics of the beetle, while the characteristics of the host plant patches may affect beetle distributions.

Key words: scaling up, elderberry longhorn beetle, metapopulation dynamics, spatial relationships