Land use intensification affects the relative importance of climate
variation and active land degradation: convergence of six regions around
the world
Abstract
We explored the relative importance of climate oscillations and
human-driven disturbances on the change of vegetation biomass in
agroecosystems, and whether it is associated with land use. The study
was carried out in the drylands of the Iberian Peninsula, NW Maghreb,
Palestinian West Bank, Mozambique, China and NE Brazil, using satellite
time-series and the corresponding climate fields, at ten-year
observation periods with spatial and temporal resolutions of 1000 m (250
m in Palestine) and one year, respectively. For each region, we
separated the relative weights of climate and time by fitting
multiple-stepwise regressions to a vegetation index as the dependent
variable, and annual aridity (Aridity) and year number (Time) as
predictors. The relative strength of the resulting standard partial
regression coefficients was then compared by the Wilcoxon Signed Ranks
test, and their combined associations with land uses were determined
using chi-square tests. Some points of convergence are: 1. The relative
weights of Aridity and Time depend on particular regional conditions and
can be determined. 2. Such weights are associated with land use
intensification, such that if vegetation increases over Time, Aridity
increases its relative importance with intensification; if vegetation is
degrading, Aridity is always more important than Time. 3. Aridity is an
indicator of vulnerability to climate warming. Resilience can be
improved by reducing land use intensification. 4. Vulnerability may
worsen under constant climate if agriculture is intensified. These
patterns enhance an integrated understanding of Sustainable Development
Goals Indicator 15.3.1, particularly its land cover and productivity
trend components.