Quantifying responses of net primary productivity to individual
agricultural land transitions in drylands
Abstract
There is limited understanding about agricultural land dynamic across
global drylands and the impacts of different agricultural land
transitions on ecosystem productivity changes. This study attempted to
fill this gap by examining the agricultural land changes and net primary
productivity responses in drylands. A data-driven assessment of the
effects on the ecosystem productivity of individual agricultural land
displacement was carried out using three methods: the mean difference
method, a newly introduced ridge-regression method, and a proposed
method based on actual change excluding climate impact. Increases in
productivity were accompanied by agricultural land transitions from
natural land covers, expected forests. The agriculture expansion mainly
replaced sparse vegetation and grassland, and increased the overall
productivity of the dryland ecosystem. Mean difference method and
ridge-regression method over overestimated the NPP increase caused by
agricultural land expansion. Land use change contributed more than 70%
to increase in net primary productivity in new agricultural area. But
land use change effects less on total productivity in drylands than
climate change. Monitoring agricultural land dynamics and distinguishing
productivity changes caused by different agricultural land transitions
is helpful to the targeted management and sustainable development of
agriculture in drylands.