Vegetation productivity in natural vs.cultivated systems along water availability gradients in the dry subtropics

• Autores: Baldi, Germán; Texeira, Marcos; Murray, Francisco; Jobbágy, Esteban G.
• Año de publicación: 2016
• Idioma: inglés
• Tipo de recurso: artículo
• Fuente: Plos One; Vol.11, no.12; e0168168; http://www.journals.plos.org
• Materia: VEGETATION; CLIMATE; DATA BASE DEFORESTATION; ECOSYSTEM; GROWING SEASON; HUMAN; HUMAN CELL; MODEL PRODUCTIVITY; SAMPLING; GROWTH, DEVELOPMENT AND AGING; SUMMER VEGETATION; WATER AVAILABILITY; PLANT DEVELOPMENT; CLIMATE CHANGE; COMPARATIVE STUDY CROP; METABOLISM; PLANT PHYSIOLOGY; TROPIC CLIMATE; WATER; CLIMATE CHANGE; CROPS AGRICULTURAL; ECOSYSTEM
• Institución: Universidad de Buenos Aires. Facultad de Agronomía

Fil: Baldi, Germán. Universidad Nacional de San Luis. Grupo de Estudios Ambientales (IMASL). San Luis, Argentina.
Fil: Texeira, Marcos. Universidad de Buenos Aires. Facultad de Agronomía. Departamento de Métodos Cuantitativos y Sistemas de Información. Buenos Aires, Argentina.
Fil: Murray, Francisco. Universidad Nacional de San Luis. Grupo de Estudios Ambientales (IMASL). San Luis, Argentina.
Fil: Jobbágy, Esteban G. Universidad Nacional de San Luis. Grupo de Estudios Ambientales (IMASL). San Luis, Argentina.
The dry subtropics are subject to a rapid expansion of crops and pastures over vast areas of natural woodlands and savannas. In this paper, we explored the effect of this transformation on vegetation productivity (magnitude, and seasonal and long-term variability) along aridity gradients which span from semiarid to subhumid conditions, considering exclusively those areas with summer rains (minor to 66%). Vegetation productivity was characterized with the proxy metric Enhanced Vegetation Index (EVI) (2000 to 2012 period), on 6186 natural and cultivated sampling points on five continents, and combined with a global climatology database by means of additive models for quantile regressions. Globally and regionally, cultivation amplified the seasonal and inter-annual variability of EVI without affecting its magnitude. Natural and cultivated systems maintained a similar and continuous increase of EVI with increasing water availability, yet achieved through contrasting ways. In natural systems, the productivity peak and the growing season length displayed concurrent steady increases with water availability, while in cultivated systems the productivity peak increased from semiarid to dry-subhumid conditions, and stabilized thereafter giving place to an increase in the growing season length towards wetter conditions. Our results help to understand and predict the ecological impacts of deforestation on vegetation productivity, a key ecosystem process linked to a broad range of services.
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