Stability of natural communities: Loop analysis and computer simulation approach

• Published in: Ecological modelling 1988, Vol.40 (2), p.131-143
• Main Authors: Giavelli, Giovanni, Rossi, Orazio, Siri, Enzo
• Format: Article
• Language: English
• Subjects: Animal and plant ecology; Animal, plant and microbial ecology; Biological and medical sciences; competition; ecology; ecosystem stability; Fundamental and applied biological sciences. Psychology; General aspects; mathematical models; predation; simulation; Synecology
• ISSN: 0304-3800; 1872-7026
• DOI: 10.1016/0304-3800(88)90107-X

The stability analysis of a natural community gives rise to conceptual and methodological problems for the ecologist. It is indeed often difficult to state or recognize when a community is stable, i.e. when it is able to return to a steady state after a displacement from equilibrium due to environmental disturbances. The evaluation of stability, based on the computation of the eigenvalues obtained from the interaction coefficients matrix, requires that one quantifies ecological processes like predation, competition etc., and these phenomena are by no means easily measured in field experiments. This study combines loop analysis and computer simulation to calculate the conditions of stability for a series of simple models of hypothetical or real communities. The simulation generates all the possible combinations of values for the coefficients related to the various models, and the stable configurations, evaluated with the loop analysis, are defined as a percentage over the total amount of cases. The results highlight in quantitative form the stabilizing role of terminal predators and the potentially destabilizing effect of competitive interactions.