Restoration recovers plant diversity but changes species composition and biomass allocation in an alpine peatland

Abstract

Background: The Zoige Plateau hosts the largest alpine peatland in the world, playing a crucial role in carbon sequestration and biodiversity conservation. However, this valuable ecosystem has been significantly impacted by anthropogenic drainage for various purposes, prompting increased interests in ecological restoration efforts. This study evaluates changes in plant diversity, community composition, and biomass allocation across natural, drained, and rewetted peatlands, with a particular focus on variations in microtopography, including hollows and hummocks. Results: Restoration showed significantly higher soil water content, which was 11.6% higher in hollows (to 88.5 ± 0.09%) and 14.4% higher in hummocks (to 81.1 ± 1.6%) of rewetted peatlands compared to natural peatlands (p < 0.001). However, the water table depth did not differ significantly from that of natural peatlands (p = 0.61). While peatland management did not significantly affect plant diversity, microtopography had a considerable impact on plant species richness, dominance, the Shannon–Wiener index, and evenness. Conversely, plant community composition exhibited significant differences among natural, drained, and rewetted peatlands at both hollow and hummock microsites. Aboveground biomass was significantly higher in drained and rewetted peatlands compared to natural peatlands at both microsites, whereas belowground biomass was significantly lower in drained and rewetted peatlands, particularly in hummocks. Conclusions: Rewetting raises water table depth but does not fully restore the original plant community composition or biomass. Microtopography plays a vital role in influencing plant diversity and community composition, with hummocks showing greater resilience to drainage impacts. Our findings emphasize ecological consequences of peatland management practices and highlight the need for targeted restoration strategies to strengthen the resilience of these vital ecosystems.