INVESTIGADORES
BALDI German
artículos
Título:
The imprint of humans on landscape patterns and vegetation functioning in the dry subtropics
Autor/es:
BALDI, GERMÁN; VERÓN, SANTIAGO R.; JOBBÁGY, ESTEBAN G.
Revista:
GLOBAL CHANGE BIOLOGY
Editorial:
WILEY-BLACKWELL PUBLISHING, INC
Referencias:
Lugar: Londres; Año: 2013 vol. 19 p. 441 - 458
ISSN:
1354-1013
Resumen:
Dry subtropical
regions, originally hosting woodlands and savannas, are subject to contrasting human
pressures and land uses and different degrees of water limitation. We quantified how this variable context
influences landscape
pattern and vegetation functioning, by exploring
the associations between three groups of variables describing (i) human pressures (population
density, poverty, and market isolation) and climate (water availability), (ii)
landscape pattern (woody cover, infrastructure, paddock size, etc.), and (iii) vegetation functioning (magnitude and stability
of primary productivity), in regions of Asia, Africa, Australia, and America. We
collected data from global socioeconomic databases and remote sensing products for 4525 samples (representing uncultivated and cultivated conditions), located along 35 transects spanning
semiarid to subhumid conditions. A Reciprocal
Averaging ordination of uncultivated samples revealed a dominant gradient of
declining woody cover accompanied by lower and less stable productivity. This
gradient, likely capturing increasing vegetation degradation, had a negative
relationship with poverty (characterized by infant mortality) and with market isolation
(measured by travel time to large cities). With partial overlaps, regions
displayed an increasing degradation ranking from Africa to South America, to Australia, to North America, and to Asia. A similar analysis of cultivated samples, showed a dominant
gradient of increasing paddock size accompanied by decreasing primary
productivity stability, which included all regions except Asia.
This gradient was negatively associated with poverty and population density. A
unique combination of small paddocks and high infrastructure differentiated Asian
cultivated samples. While water availability gradients were related to
productivity trends, they were unrelated to landscape pattern. Our comparative
approach suggests that, in dry subtropical regions, human pressures have an
overwhelming role driving landscape patterns and one shared with water
availability shaping vegetation functioning.