Dynamical phase coexistence: A simple solution to the "savanna problem"

Details Dynamical phase coexistence: A simple solution to the "savanna problem" Dynamical phase coexistence: A simple solution to the "savanna problem"

2010-03-08

arxiv.org/abs/1003.1711v1

Physics

Biological Physics

8 pages, 7 figures. Accepted for publication in Journal of Theoretical Biology

Scientific paper

10.1016/j.jtbi.2010.02.011

We introduce the concept of 'dynamical phase coexistence' to provide a simple solution for a long-standing problem in theoretical ecology, the so-called "savanna problem". The challenge is to understand why in savanna ecosystems trees and grasses coexist in a robust way with large spatio-temporal variability. We propose a simple model, a variant of the Contact Process (CP), which includes two key extra features: varying external (environmental/rainfall) conditions and tree age. The system fluctuates locally between a woodland and a grassland phase, corresponding to the active and absorbing phases of the underlying pure contact process. This leads to a highly variable stable phase characterized by patches of the woodland and grassland phases coexisting dynamically. We show that the mean time to tree extinction under this model increases as a power-law of system size and can be of the order of 10,000,000 years in even moderately sized savannas. Finally, we demonstrate that while local interactions among trees may influence tree spatial distribution and the order of the transition between woodland and grassland phases, they do not affect dynamical coexistence. We expect dynamical coexistence to be relevant in other contexts in physics, biology or the social sciences.

Affiliated with

Also associated with

No associations

Rating

Dynamical phase coexistence: A simple solution to the "savanna problem" does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.

If you have personal experience with Dynamical phase coexistence: A simple solution to the "savanna problem", we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Dynamical phase coexistence: A simple solution to the "savanna problem" will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFWR-SCP-O-453935