Non-linear ecological processes, fires, environmental heterogeneity and shrub invasion in northwestern Patagonia |
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Authors: | L. Ghermandi M.I. de Torres Curth J. Franzese S. Gonzalez |
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Affiliation: | Lab. Ecotono, INIBIOMA, CONICET-CRUB-UNCo, Quintral 1250, 8400 Bariloche, Argentina |
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Abstract: | The emergent behaviors of nature are not only the sum of interactions among ecosystem parts but also depend on the organization of these interactions. Fire, climate and vegetation patterns produce non-linear fire propagation across the landscape. Environmental heterogeneity, like outcrop presence and hare density, increases landscape patchiness and makes possible the occupation of fire refuges by plants, like Fabiana imbricata shrubs. We monitored shrub recruitment and cover during nine postfire years in northwestern Patagonia grasslands and we studied the long-term population dynamics under different environmental conditions through a matrix model, exploring different fire frequencies and spring precipitation regimes. Both, the field monitoring and the model seem to confirm the relationships between shrub invasion and fire. The climate change forecast predicts an increase in the frequency of El Niño Southern Oscillation phenomena that could causes more coupled fires—rainy springs in northwestern Patagonia, and consequently, more recruitment windows for shrubs, like F. imbricata. The matrix model also indicates that this scenario would be the most favourable for shrub invasion. Our results contribute to the knowledge of the ecosystem properties and processes, providing useful information to improve the grasslands sustainable use. |
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Keywords: | Climate change El Niñ o Southern Oscillation Elasticity Fabiana imbricata Fire Landscape Megamatrix Patagonia Shrub invasion |
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