Introduction
Vegetation communities in arid and semi-arid regions are vulnerable to
the effects of global climate change (Peters et al., 2012; Na et
al., 2021; Li et al., 2021). Vegetation is the most important
condition to maintain the ecosystem function in arid and semi-arid
areas. Therefore, it is very important to maintain the diversity and
stability of vegetation communities in these areas. (Jin et al.,2019). The dry-semi-arid regions in northwestern China have the world’s
important pasture and the distribution area of the world’s important
grass ecosystem. Due to the grassland vegetation protection system
attributed to the Chinese government, most of these grass ecosystems
facing artificial interference are limited to grazing activities. Some
studies have pointed out that the climate model in northwestern China
has undergone significant warm and humidization changes in recent
decades. Therefore, it is necessary to study the mechanism of changes in
the diversity of grassland vegetation in the northwest of China and semi
-arid regions under the dual pressure of grazing and climate change.
Climate change and grazing are important stressors affecting grassland
ecosystem stability (Li et al., 2015; Jiang et al., 2017).
Precipitation is almost the only water source for inland grassland.
Long-term precipitation changes will lead to obvious succession of
vegetation communities, and some arid plants are more sensitive to
precipitation changes (Vicente-Serrano et al., 2012). Temperature
is also considered to be an important factor affecting vegetation growth
and water cycle (Fensholt et al., 2012; Na et al., 2021).
In addition, there is an interaction between surface vegetation and
local climate. Low temperature, high biomass and high coverage
vegetation can maintain a humid climate. The stability of the
interaction between vegetation and climate may be weakened by the
destruction of vegetation and the rise of temperature caused by external
disturbances (Claussen et al., 2013). Overgrazing resulted in the
loss of vegetation diversity and the reduction of community stability,
resulting in the collapse of grassland ecosystem and promoting
desertification。Continuous grazing activity will change the vegetation
species composition of grassland, resulting in the disappearance of
wet-loving vegetation and the replacement of grassland by
drought-tolerant shrubland, resulting in the decline of grassland
productivity and pasture carrying capacity (Vicente-Serrano et
al., 2012). However, the interaction between climate change and human
grazing activities on vegetation is currently unclear (He et al.,2022).
In the grassland areas in northwestern China, the local government
proposed a series of strict management systems in order to avoid the
irreversible damage of vegetation in arid areas. Therefore, in these
areas, grazing is a controlled behavior that is constrained, while the
effects of climate change on vegetation are uncontrollable and
unavoidable. The role of climate in influencing vegetation diversity and
maintaining vegetation-climate stability in the context of grazing
intensity changes needs to be reexamined. In addition, under the global
trend of long-term climate change, the ability of vegetation communities
in arid areas to maintain vegetation-climate stability in response to
grazing disturbance also needs more understanding. Therefore, the
interaction analysis of climate and grazing activities on vegetation is
needed to develop more scientific and economic grazing management
strategies, and to better understand the impacts of climate change on
vegetation in arid areas.
Vegetation survey was carried out on five grasslands with distinct
climatic differences in arid and semi-arid regions of northwest China.
The relationship between Simpson, Shannon and Pielou index of vegetation
and grazing intensity, temperature and precipitation were analyzed. The
effects of grazing activities and climate differences on vegetation
diversity and stability were discussed. In addition, the variation
trends of dominant species and individual height under the dual effects
of grazing intensity and climate were analyzed, and the reasons for the
interaction were explained from the species structure. Our results
contribute to the understanding of vegetation change mechanisms in arid
and semi-arid regions in the context of climate change and grazing
management system reform.