21. Study area
The study area (214,100 km2) is the Great Taihang
Region (34° 34′ ~ 40° 47′ N, 110° 14′ ~
116° 34′ E),located in the north of China and covers the entire
territory of Shanxi province, as well as some districts and counties in
Beijing, Hebei and Henan provinces, accounting for about 2.2% of
China’s terrestrial area (Fig. 1). In the study area, cropland covers
37% of this area, forest 35%, and Grassland 21%. There are various
geomorphic types, including mountains, hills, platforms and plains. The
eastern part is a massive mountain formed by the Taihang Mountain, and
the western part is the Loess Plateau with Lvliang Mountain as the trunk
(Fig. 2). The altitude ranges between 24 m to 3091 m. The climate in
this region is temperate continental monsoon climate and
the four seasons is distinct, with mean annual temperature between 8 and
13°C, and average annual precipitation between 400 and 1000 mm. Rainfall
is concentrated from July to September. Deciduous broad-leaved forest is
the most widely distributed plant community in the study area. Deciduous
broad-leaved forest and secondary deciduous shrub are mainly distributed
in the South, while temperate shrub and semi-arid grassland located in
the northern part. The study area is mainly mountainous area, and the
diversity of geographical environment leads to a good variety of flora
and fauna.