Catastrophic regime shifts in model ecological communities are true phase transitions - Quantitative Biology > Populations and EvolutionReportar como inadecuado




Catastrophic regime shifts in model ecological communities are true phase transitions - Quantitative Biology > Populations and Evolution - Descarga este documento en PDF. Documentación en PDF para descargar gratis. Disponible también para leer online.

Abstract: Ecosystems often undergo abrupt regime shifts in response to gradual externalchanges. These shifts are theoretically understood as a regime switch betweenalternative stable states of the ecosystem dynamical response to smooth changesin external conditions. Usual models introduce nonlinearities in themacroscopic dynamics of the ecosystem that lead to different stable attractorsamong which the shift takes place. Here we propose an alternative explanationof catastrophic regime shifts based on a recent model that pictures ecologicalcommunities as systems in continuous fluctuation, according to certaintransition probabilities, between different micro-states in the phase space ofviable communities. We introduce a spontaneous extinction rate that accountsfor gradual changes in external conditions, and upon variations on this controlparameter the system undergoes a regime shift with similar features to thosepreviously reported. Under our microscopic viewpoint we recover the mainresults obtained in previous theoretical and empirical work anomalousvariance, hysteresis cycles, trophic cascades. The model predicts a gradualloss of species in trophic levels from bottom to top near the transition. Butmore importantly, the spectral analysis of the transition probability matrixallows us to rigorously establish that we are observing the fingerprints, in afinite size system, of a true phase transition driven by backgroundextinctions.



Autor: Jose A. Capitan, Jose A. Cuesta

Fuente: https://arxiv.org/







Documentos relacionados