Effects of enclosure on vegetation diversity and niche characteristics of different grassland types in Xinjiang

To explore the response of vegetation diversity and enclosure niche, different grassland types (temperate desert, temperate steppe, and temperate montane meadow grasslands) in Xinjiang were the research object. Vegetation diversity and niche characteristics in the study sites were measured and analyzed by combining field sampling and indoor analysis. The enclosure treatment results of the different grassland types revealed that except for temperate desert grassland, most species in temperate steppe and mountain meadow grasslands showed higher niche breadth indices than grazing plots after enclosure treatment. The effect of the enclosure was more obvious in temperate steppe and mountainous meadow grasslands. Compared to freely grazing areas, temperate steppe grassland Shannon-Wiener, Patrick, Pielou, and Simpson indices increased significantly by 31.81%～90.80% (P < 0.05) after enclosure. These results indicated that enclosure treatment had the best effect in temperate steppe grassland. In conclusion, enclosure for 10 years can promote vegetation restoration of steppe and mountain meadow grasslands but inhibits vegetation restoration of desert grassland. Thus, the responses of different grassland types to fencing can differ significantly. The study findings highlight that in the governance and restoration of degraded grassland, reasonable enclosure measures should be formulated in combination with various factors, such as vegetation type and vegetation growth environment, to achieve a better enclosure effect.