PARENT SESSION
Poster Session 23: Ecological Theory.
Wednesday, August 4 Presentations from 5:00 PM to 6:30 PM, Exhibit Hall A 1.
Assessing the importance of initial conditions on community dynamics using long-term manipulations of a Chihuahuan Desert community.
Ernest, Morgan*,1, 1 University of New Mexico, Albuquerque, NM, USA
ABSTRACT- The importance of the initial conditions on the subsequent trajectory of a system has long been discussed, especially with regards to chaos theory. In ecology, our understanding of the ability for the current state of the system to influence its response to perturbation is important for predicting responses to disturbance. Here I examine whether differences in the initial conditions at the inception of a long-term press experiment affect the long-term dynamics of three different taxonomic groups in the Chihuahuan Desert. The experimental site I used in this study has been monitoring the responses of rodents, ants, and plants to continuous experimental manipulations of the rodent and ant community since 1977 (referred to here as long-term treatments). A second set of manipulations, identical to the manipulations initiated in 1977, were implemented in 1989 (short-term treatments). Comparisons of the communities on the long-term and short-term treatments indicate that even after 13 years under identical experimental manipulations the communities have shown important differences in their temporal dynamics. While these communities appear to begin to converge with regards to species composition over the first half of the study, remaining differences in community composition appear to result in different responses to ambient perturbations (e.g. droughts/floods, colonization events) in the second half of the study. These results suggest that while communities receiving the same perturbation but with different initial conditions tend to converge, secondary perturbations can prevent this convergence and send the community down an alternative temporal trajectory.
Key words: Chihuahuan Desert, plants, temporal community dynamics, rodents and ants