Distribution of land-use types and dynamics of environmental
factors
PCoA biplots show that the land-use types of the Weihe River were
markedly different from those of the Hanjiang River and Qinling
tributaries,
with the first axis explaining 87.88% of the variation in land-use type
(Fig. 2a). In Weihe River, agricultural land was the primary land-use
type, accounting for
61.22±12.58%
of total land area. In addition, the area proportion of urbanized land
in Weihe River was significantly higher than those in the other two
regions (Fig. 2b). Forest was the main land-use type in the Hanjiang
River and Qinling tributaries, accounting for 60.88±5.85% and
64.91±12.48% of total land area, respectively. According to the
distributions of different land-use types, the river areas were
dominated by agricultural or forest land. Specifically, the Weihe River
area mainly comprised agricultural land, grassland, and urbanized land;
the Hanjiang River area mainly hosted forest, agricultural, and shrub
land; and the Qinling tributary area was dominated by forest and shrub
land.