Dynamics of Grassland Vegetation Composition across different Land-use Types on the Qinghai Tibet Plateau: Implications to Combat Grassland Degradation

Abstract

The constant biotic and abiotic interventions on the Qinghai Tibet Plateau (QTP) are seriously degrading the grasslands and, at the same time, restricting the active ecosystem function and grassland vegetation distribution on the plateau. This research analyses the dynamics of grassland vegetation composition across three land uses and counties. The degree of grassland degradation was divided into four land-use types based, i.e., healthy grassland (HG), restored grassland (RG), moderately degraded (MD) grassland, and severely degraded (SD) grassland. About 32 plant species were recorded in Tiebujia county, 28 in Maqin county, and 18 in Maduo county. Results showed Poa crymophila, Polygonum sibiricum, Leontopodium nanum and Oxytropis falcatabunge as the most abundant grassland species in all land-uses and counties. The richness of species ranged from 8 to 12 species per land-use, suggesting low richness and diversity in restored and degraded grassland. A positive non-significantly mean change (p<0.05) was detected for richness and evenness indices while a negative mean change (p<0.05) was detected for Simpson and Shannon indices in the alpine meadow and steppe in both Maqin and Maduo county. The results imply that degradation affects grassland vegetation, health, and distribution across the QTP. Plant total cover for the healthy grassland covered far more areas than other land-uses. Urgent mitigation measures to halt grassland degradation and decline in plant vegetation composition on the plateau should be adopted.