Ecological Effects of Grazing in the Northern Tianshan Mountains

Abstract

Abstract:Identifying the effects of grazing is critical for the conservation, protection and sustainable use of arid grassland ecosystems. However, research regarding the ecological effects of grazing along mountainous elevation gradients is limited in arid areas, particularly at the regional scale. Using the Biome-BGC grazing model, we explored the effects of grazing on grassland net primary productivity (NPP), evapotranspiration (ET) and water use efficiency (WUE) from 1979 to 2012 along an elevation gradient in the northern Tianshan Mountains. The NPP, ET and WUE values were generally lower under the grazing scenario than under the ungrazed scenario; the differences between the grazing and ungrazed scenarios showed increasing trends over time; and distinct spatial heterogeneity in these differences was observed. Distinct decreases in NPP and WUE under the grazing scenario mainly occurred in regions with high livestock consumption. The decrease in ET was greater in mountainous areas with high grazing intensity due to decreased transpiration and increased surface runoff. This study contributes to a better understanding of the ecological effects of grazing along an elevation gradient in the northern Tianshan Mountains and provides data to support the scientific management of grassland ecosystems.

Recent responses of grassland net primary productivity to climatic and anthropogenic factors in Kyrgyzstan

“…Quantifying the spatio‐temporal variation in NPP is extremely important for ecosystem maintenance and related policy‐making in Kyrgyzstan (Huang, Luo, He, Wang, & Amuti, 2017; Sagynbekova, 2017). NPP in terrestrial ecosystems has been widely investigated at both global and regional scales using integrated and advanced techniques (Awaya et al, 2004; Luo et al, 2018; Running et al, 2004).…”

How precipitation and grazing influence the ecological functions of drought-prone grasslands on the northern slopes of the Tianshan Mountains, China?

“…The Tianshan Mountains are located in the hinterland of Eurasia; arid grasslands are widely distributed in this region (Luo et al, 2012;Huang et al, 2017a; and are an important base for animal husbandry production (Liu et al, 2016). They also provide a natural laboratory for studying how precipitation influences the ecological functioning of drought-prone grasslands (Luo et al, 2012).…”

“…Luo et al (2012) used model simulations to show that moderate grazing can increase the ANPP of grasslands under water stress conditions, but their results have not been verified by experimental data. There has been no systematic and explicit investigation into how precipitation and grazing influence AGB, SVWC, and PUE in the Tianshan Mountains, although it is known that precipitation is the most significant factor limiting plant growth in the region (Huang et al, 2017a;Gherardi and Sala, 2019). Moreover, the relatively large interannual variation in precipitation observed in the Tianshan Mountains (Xu et al, 2018) may result in interannual differences in plant growth.…”

“…Moreover, the relatively large interannual variation in precipitation observed in the Tianshan Mountains (Xu et al, 2018) may result in interannual differences in plant growth. The increase in grazing intensity has led to serious degradation of grasslands in this region (Huang et al, 2017a. Thus, there is an urgent need to understand how both precipitation and grazing affect interannual plant growth in drought-prone grasslands of the Tianshan Mountains.…”

Aboveground Biomass Dynamics in the Low-Mountain Dry Grasslands of the Tianshan Mountains

“…The Tianshan Mountains are an important region for animal husbandry, and low-mountain dry grasslands (LMDG) are widely distributed in this area [7]. Because of the influence of the arid climate, these grasslands are ecologically fragile.…”