PARENT SESSION
Symposium 21: Miniature Worlds? Natural Microcosms as Model Ecological Systems
Organized by: D Srivastava and J Kolasa
Thursday, August 7. 1:30 PM to 5:00 PM, SITCC Chatham Ballroom C.

Testing metacommunity concepts with density manipulations of Pen shell (Atrina rigida) communities.

Munguia, Pablo^*,1, ¹ Deartment of Biological Sciences, Tallahassee, Florida, United States

ABSTRACT- Mechanisms acting on different spatial scales have not been easy to understand because of difficulties in conducting large-scale experiments. Further, species vary in their perception of space (related to behavior) and time (related to life history), making it difficult to interpret patterns of diversity and richness. Therefore, a community must be understood as a mélange of species, where forces acting at the community level will have different effects depending on the individual and combined responses of component species. Here I present a model benthic system used to address community-level mechanisms acting at different spatial scales. At St. Joe Bay, Florida, the pen shell (Atrina rigida) is one of the few sources of hard substrate, serving as a habitat for both sessile and mobile invertebrates, as well as fish. Habitat was constructed at different scales by anchoring empty shells in arrays of varying density. Treatments included age of the community, distance from the nearest community, as well as simulated destruction of communities. The effects of these treatments varied depending on the group of species present on a pen shell. Pen shell communities exhibit species successional patterns that affect the relationship between spatial scales. Furthermore, these patterns seem to differ depending on the life history of the group of species. In order to understand how mechanisms that produce patterns of relative abundance and species richness change with scale, we must take into account the natural history of the component species.

Key words: species diversty, habitat isolation, benthic system, spatial scale