Vegetation Productivity in Natural vs. Cultivated Systems along Water Availability Gradients in the Dry Subtropics

• Published in: PloS one Vol. 11; no. 12; p. e0168168
• Main Authors: Baldi, Germán, Texeira, Marcos, Murray, Francisco, Jobbágy, Esteban G.
• Format: Journal Article
• Language: English
• Published: United States Public Library of Science 22.12.2016; Public Library of Science (PLoS)
• Subjects: Agricultural productivity; Agriculture; Analysis; Annual variations; Aridity; Availability; Biology and Life Sciences; Climate Change; Climate models; Climatology; Continents; Crops; Crops, Agricultural - growth & development; Cultivation; Cultivation (Land); Deforestation; Deforestation effects; Earth Sciences; Ecological effects; Ecology and Environmental Sciences; Ecosystem; Efficiency; Environmental aspects; Genetic transformation; Global climate; Growing season; Interannual variability; Pasture; People and Places; Physical Sciences; Plant Development; Plant Physiological Phenomena; Precipitation; Productivity; Remote sensing; Savannahs; Seasonal variability; Subtropical climates; Topography; Transformation; Tropical Climate; Variability; Vegetation; Vegetation index; Water - metabolism; Water availability; Woodlands; Argentina; Pakistan; Queensland Australia; Australia; India
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0168168

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 (>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.