Spatial distribution characteristics and drivers of throughfall beneath
artificial revegetation shrub canopies in a semi-arid desert steppe
Abstract
The spatial distribution of water is mainly controlled by the vegetation
canopy, which determines the partitioning of rainfall into interception,
throughfall (TF), and stemflow. Spatiotemporal patterns of TF have been
studied in different ecosystems, though the majority of studies focused
on forests. Few reports on small-scale TF variability and drivers in
semi-arid desert steppes have been published. Herein, we investigated
the variability of TF of two morphologically distinct artificial
revegetation shrubs ( Caragana liouana and Salix
psammophila) within a semi-arid desert steppe, synthesized the data,
and analyzed the characteristics of TF distribution and drivers at the
rainfall event scales. We found that: (1) morphological differences were
sufficient to generate significant (P < 0.05) differences in
TF between the two shrub species; (2) Wind speed had a greater effect on
the distribution of TF beneath the shrub structure for C.
liouana, while the distribution of TF beneath the shrub structure for
S. psammophila was more affected by wind direction; and (3)
canopy architecture, in particular the stem angle and canopy base area,
which affected the openness of the canopy and played an important role
in the distribution of TF in the two shrubs. For C. liouana,
larger shrubs had higher TF, while for S. psammophila, smaller
shrubs had higher TF. The results reveal the key factors driving water
use under rainfall during revegetation and the TF utilization mechanism
in semi-arid areas, and highlight the complementary effect of different
species on ecosystem hydrological functions.