Divergent driving mechanisms of community temporal stability in drylands
of China
Abstract
Climate change and human activities are changing the structure and
function of dryland ecosystems at unprecedented rate, thus threatening
the stability of ecosystems. The stability of dryland ecosystems is
vital for ecological security and local livelihoods. However, the
mechanisms that underlie ecosystem stability in drylands remain
uncertain due to limited field data from regional studies. Combined with
transect survey in the drylands of China along the aridity gradient and
remote sensing data, we characterized community temporal stability and
identified its driving mechanisms along the aridity gradient. The
results showed the community temporal stability in drylands of China
revealed a U-shaped curve with increasing aridity and its major driving
mechanisms shifted at an aridity level of ~0.88. In
regions where aridity is below 0.88, increasing precipitation and
species richness resulted in higher community productivity and community
stability. In regions where aridity is above 0.88, however, higher soil
organic carbon content and species richness may lead to higher
variability of community productivity and lower ecosystem stability.
Overall, our findings revealed that there existed an aridity threshold
leading to abrupt changes on community stability in drylands of China.
Our study also suggested divergent driving mechanisms of community
stability above and below the threshold, which should be considered in
policy making regarding the ecosystem management of drylands.