Synergies between microsites of plant communities and steady-stage alpine meadows on the Qinghai–Tibetan Plateau

Abstract

Background

Due to the effects of climate change and overgrazing in recent decades, alternative stable states in the alpine Kobresia meadow degradation process have coexisted in the same geographical and climatic environment, with variations occurring among microsites.

Methods

We used a space-for-time substitution approach to explore the synergies of microsite variation according to its numerical characteristics and the proportion of each stable state at various stages of succession in alpine Kobresia meadows on the Qinghai–Tibetan Plateau.

Results

(1) The highest average aboveground biomass in summer was 196.2 ± 20.3 g m⁻², with significantly higher levels of biomass in ≤3.65 sheep unit ha⁻¹ than in other levels of grazing intensity, while the parameters showed no significant differences among grazing intensity levels in >3.65 sheep unit ha⁻¹. (2) The importance of plant functional groups, aboveground biomass, and niche breadth of Poaceae and Cyperaceae significantly decreased as the grazing intensity increased. (3) The effects of ≥0°C accumulated temperature, total precipitation, altitude, longitude, and latitude cumulatively contributed less than 20% of the variation in the distribution of functional group characteristics across microsites.

Conclusions

(1) Overgrazing decreases primary production in alpine Kobresia meadows, but ecosystem responses regulate plant community structure and botanical components so as to partially counteract grazing disturbance. (2) Overgrazing changed the proportion of microsites, which in turn led to regime shift in the plant community and subsequent synergies between the microsites of plant communities and their stable states.