Effects of decade-long grazing exclusion and wind erosion reduction on community temporal stability in a semi-arid grassland.
Abstract
1. Ecological restoration can help rehabilitate degraded grasslands and mitigate desertification and wind erosion. Grazing exclusion (GE), a prominent restoration practice, in conjunction with wind erosion reduction (WR) can have profound impacts on the long-term stability of grassland plant communities. However, this area remains underexplored, which poses challenges for developing policies that support sustainable grassland management. 2. This study, part of a decade-long (2010-2019) field experiment, investigated the effects of GE and WR on the temporal stability of plant communities in a semi-arid grassland on the Mongolian Plateau, China. The study also explored the underlying regulatory mechanisms driving these stability dynamics. 3. Over the 10-year period, GE increased total community cover by restoring the cover of tall-stature species, which resulted in sub-canopy light limitation and a reduction in the richness of short-stature species and the overall community. Despite species loss due to GE, species asynchrony remained unaffected. In contrast, GE improved the population stability of tall-stature species, contributing to a marginal increase in community temporal stability (CTS). Wind erosion reduction stimulated total community cover by enhancing the cover of both tall- and short-stature species. However, WR decreased the richness of short-stature species and the overall community. Exacerbated water stress, resulting from increased cover of short-stature species under WR, suppressed CTS. In addition, the elevated soil nitrogen (N) concentration associated with WR further diminished CTS by reducing the temporal stability of short-stature species. 4. Synthesis and applications. Our findings highlight that while GE supports the recovery of dominant tall-stature species and promotes their population stability, grassland communities recovering after WR face challenges such as water deficit and excessive N enrichment, leading to long-term stability loss. Furthermore, the loss of short-stature species under both GE and WR may disrupt grassland trophic relationships and destabilize food webs. Future sustainable management strategies should incorporate periodic or rotational grazing to alleviate sub-canopy light limitation, enhance soil N uptake, and reduce water demands, which could help maintain the temporal stability of temperate grassland communities.