The ecohydrology of ecosystem transitions: a meta‐analysis

• Autores: Viglizzo, Ernesto Francisco; Nosetto, Marcelo Daniel; Jobbagy Gampel, Esteban Gabriel; Ricard, Maria Florencia; Frank, Federico Carlos
• Año de publicación: 2015
• Idioma: inglés
• Tipo de recurso: artículo
• Fuente: Ecohydrology 8 (5) : 911-921. (July 2015)
• Materia: Hydrology; Ecosystems; Evapotranspiration; Resilience; Anthropogenic Factors; Woody Plants; Hidrología; Ecosistema; Evapotranspiración; Resiliencia Frente a Impactos y Crisis; Factores Antropogénicos; Plantas Leñosas; Ecosystems Conversion
• Institución: Instituto Nacional de Tecnología Agropecuaria

A vast body of literature demonstrated that anthropogenic disturbances such as overgrazing and fire are key drivers of abrupt transition between vegetation types in ecosystems. In this study, we propose that the hydrological context (described in terms of rainfall, evapotranspiration and water yield) is a first‐order, primordial determinant of the propensity of ecosystems to undergo transition. This implies that the anthropogenic disturbance is a second‐order determinant that is strongly conditioned by the first one. Through the meta‐analysis of existing studies, a collection of 685 geo‐referenced study cases was organized to study the hydrological characteristics of three climatic regions and three ecosystems that vary in their relation between woody and grassy plants. Thus, humid, sub‐humid and dry climatic regions, respectively, receiving >1000, 500–1000 and <500 mm year−1, were studied, and possible transition mechanisms among grasslands/savannas, shrublands and forests were analysed. The results showed that the ecohydrological context determines the probabilities of ecosystems transitions in different climatic regions and the prevalence of alternative transition mechanisms. We showed that transition of forests into other ecosystems is highly improbable in high‐precipitation regions, more probable and likely subject to a bi‐stable and reversible regime in sub‐humid regions, and highly probable and irreversible in dry regions. Factors such as runoff, deep‐water drainage, fire, flammable/nonflammable biomass and overgrazing were considered as hypothetical transition mechanisms. As a novel finding, we demonstrate that ecohydrology, as a determinant of transition, is a factor that operates at a hierarchical level higher than that of the human‐driven disturbance. A synthetic graphical model was proposed to characterize resilience (the capacity of ecosystems to withstand transition) in the three study climatic regions.
EEA Anguil
Fil: Viglizzo, Ernesto Francisco. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Anguil; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Ciencias de la Tierra y Ambientales de La Pampa. Universidad Nacional de La Pampa. Facultad de Ciencias Exactas y Naturales. Instituto de Ciencias de la Tierra y Ambientales de La Pampa; Argentina. Universidad Nacional de La Pampa. Facultad de Ciencias Exactas y Naturales; Argentina
Fil: Nosetto, Marcelo Daniel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico San Luis. Instituto de Matemática Aplicada de San Luis; Argentina
Fil: Jobbagy Gampel, Esteban Gabriel. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Matemática Aplicada de San Luis "Prof. Ezio Marchi". Universidad Nacional de San Luis. Facultad de Ciencias Físico, Matemáticas y Naturales. Instituto de Matemática Aplicada de San Luis; Argentina
Fil: Ricard, Maria Florencia. Consejo Nacional de Investigaciones Cientificas y Tecnicas. Instituto de Ciencias de la Tierra y Ambientales de la Pampa; Argentina
Fil: Frank, Federico Carlos. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Anguil; Argentina. Universidad Nacional de La Pampa. Facultad de Ciencias Exactas y Naturales; Argentina