Richness, not evenness, of invasive plant species promotes invasion success into native plant communities via selection effects

Increasing plant diversity enhances soil organic carbon storage in typical wetlands of northern China

Soil organic carbon plays an important role in climate change mitigation, and can be strongly affected by plant diversity. Although a positive effect of plant diversity on soil organic carbon storage has been confirmed in grasslands and forests, it remains unclear whether this effect exists in wetlands. In this study, we investigated plant diversity, soil properties and soil organic carbon across five typical wetlands of northern China, to test the effect of plant diversity on soil organic carbon and clarified the regulators. Increasing plant diversity significantly increased belowground biomass of wetland plant communities, and both soil organic carbon content and storage were significantly positively related to wetland plant diversity. The positive effect of plant diversity was influenced by belowground biomass of wetland plant communities, soil microbial biomass carbon, and soil properties, especially soil water content and bulk density. The structural equation model showed that soil organic carbon storage was dominantly affected by microbial biomass carbon, plant diversity and biomass, with standardized total effects of 0.66 and 0.47, respectively, and there was a significant positive relationship between soil organic carbon and microbial biomass carbon. These results suggest that increasing plant diversity can potentially promote the ability of wetlands to store organic carbon in soils. The findings highlight the importance of plant diversity on soil organic carbon in wetland ecosystems, and have implications for managing wetlands to increase carbon sinks and to mitigate global climate change.

Effects of alligator weed invasion on wetlands in protected areas: A case study of Lishui Jiulong National Wetland Park

Wetlands are one of the ecosystems most easily and severely invaded by alien species. Biological invasions can have significant impacts on local plant communities and ecosystem functioning. While numerous studies have assessed the impacts of biological invasions on wetlands, relatively few have been conducted in protected areas such as national wetland parks. We conducted a field survey to investigate the effects of the invasive herb Alternanthera philoxeroides (alligator weed) on the productivity and structure of plant communities and soil microbial communities in the Lishui Jiulong National Wetland Park in Zhejiang, China. We also examined the potential influence of the distance to the river edge on the impact of the alligator weed invasion. The alligator weed invasion significantly altered the plant community structure. It reduced the coverage of co-occurring plant species, including native (-31.2 %), invasive (-70.1 %), and non-invasive alien plants (-58.4 %). However, it increased species richness by 50 %, Pielou's evenness by 20 %, and Simpson's diversity index by 29.1 % for the overall plant community. Furthermore, within the community not invaded by alligator weed, increasing the distance to the river edge decreased the number of native plants by 57.0 % and the aboveground biomass of other invasive plants by 78.6 %. Contrary to expectations, no effects of the alligator weed invasion were observed on soil fungal and bacterial communities. Therefore, the impacts of the alligator weed invasion varied with spatial context and plant category, emphasizing the need to consider multiple scales and environmental factors when assessing the effects of invasive species on plant biodiversity. These insights enhance our understanding of plant invasions in wetlands and can guide the development of effective management strategies for these important ecosystems.

Unveiling the resistance of native weed communities: insights for managing invasive weed species in disturbed environments

Weed communities influence the dynamics of ecosystems, particularly in disturbed environments where anthropogenic activities often result in higher pollution. Understanding the dynamics existing between native weed communities and invasive species in disturbed environments is crucial for effective management and normal ecosystem functioning. Recognising the potential resistance of native weed communities to invasion in disturbed environments can help identify suitable native plants for restoration operations. This review aims to investigate the adaptations exhibited by native and non-native weeds that may affect invasions within disturbed environments. Factors such as ecological characteristics, altered soil conditions, and adaptations of native weed communities that potentially confer a competitive advantage relative to non-native or invasive weeds in disturbed environments are analysed. Moreover, the roles of biotic interactions such as competition, mutualistic relationships, and allelopathy in shaping the invasion resistance of native weed communities are described. Emphasis is given to the consideration of the resistance of native weeds as a key factor in invasion dynamics that provides insights for conservation and restoration efforts in disturbed environments. Additionally, this review underscores the need for further research to unravel the underlying mechanisms and to devise targeted management strategies. These strategies aim to promote the resistance of native weed communities and mitigate the negative effects of invasive weed species in disturbed environments. By delving deeper into these insights, we can gain an understanding of the ecological dynamics within disturbed ecosystems and develop valuable insights for the management of invasive species, and to restore long-term ecosystem sustainability.