Clonal trait diversity in relation to invasiveness of alien macrophytes in two Himalayan Ramsar sites

Questions In view of the predominance of clonality in aquatic plants and its likely role in plant fitness, we specifically asked whether or not clonality contributes to invasiveness of macrophytes. We also aimed to explore clonal trait diversity in alien aquatic plants and evaluate its implications in the context of species invasiveness. Location Two Ramsar sites: Hokersar Wetland and Lake Wular, Kashmir Himalaya, India. Methods Extensive field surveys were carried out in the two target Ramsar sites. The clonal growth form categorization was done using the CLO-PLA 3 (clonal plant) database of clonal growth in plants, and the relationship between clonality and invasiveness was examined. We used a stage-based hierarchical model to categorize the investigated species into different stages of invasion (Stages II, III, IVa, IVb, V) and examine proportion of clonality at various stages of invasion. Results A total of 62 wetland plant species were recorded, most of which (58) were alien invasives. We characterized the clonal growth organ (CGO) spectra in the target plant species and categorized them into four space occupancy strategies (i.e. spreading, non-spreading, splitters and integrators). More than 90% of the studied plants were clonal with a tendency of increasing clonality in plants belonging to higher stages of invasion (Stage V). Conclusions The present study revealed a significant positive correlation between clonality and species invasiveness, thereby indicating the likely contribution of clonality to invasion success. Given the paucity of studies on the contribution of clonality in invasiveness of alien species, our results have significant implications for invasion management in wetland systems.