Assembling Stable Ecological Communities Chris Wilmers, Sitabhra Sinha and Markus Brede
Outline
Motivation
PowerPoint Presentation
Slide 5
Slide 6
Slide 7
Slide 8
Slide 9
Definitions
Measures of Stability
Measures of Stability cont.
The Empiricist's View: Biodiversity is essential for maintaining community stability
Experimental evidence: Common garden experiments (e.g. Cedar Creek)
Slide 15
and more resistant
Experimental evidence: Bottle Experiments (e.g. Ecotron)
Slide 18
The Theoretician's View Increasing complexity leads to instability consider a simple community of one predator and one prey.
Robert May (1972) - analyzed the properties of randomly generated community matrices of,
Slide 21
The Model
Model cont.
initial growth is monotonic
Community growth and collapse is more correlated than a random walk.
Slide 26
stability probability density of our model vs. what we would have expected if the system had only one-step memory.
Frequency histograms for communities with different average interaction strength
Slide 29
Comparison to May (1972)
Larger communities are less variable
Extinction cascades: Ratio of large to small cascades increases for decreasing community size
Larger communities are more resilient
Root mean square fluctuations
Comparing food webs to community networks
New rule: if ï¬ > 0, then eliminate the species corresponding to the most negative component of the eigenvector corresponding to the largest eigenvalue of the Jacobian A.
new rule
Provisional results:
Slide 39
Slide 40
Acknowledgements
Author: Sitabhra Sinha
E-mail: sitabhra@imsc.res.in
Homepage: http://www.imsc.res.in/~sitabhra/
Best viewed with
