Variation in Plant Functional Composition of the Afromontane Palustrine Wetlands Along an Altitudinal Gradient in Lesotho

Abstract

Understanding montane wetlands and their functioning is essential for biodiversity conservation and sustainable provision of ecosystem services. Plant functional traits represent species adaptations to specific environments and are considered the key mechanism by which individual species contribute to the functioning and subsequent provision of ecosystem services. This study characterises the Afromontane palustrine wetlands along the altitudinal gradient in Lesotho in terms of plant functional traits and composition. Wetland plant species are classified into functional types (PFTs) using their functional traits. Relationships of plant functional traits and PFTs with environmental factors are also explored. Plant species composition was assessed using the Braun-Blanquet method, while functional traits and environmental factors were assessed using protocols recommended in the literature. The data were analysed using clustering and ordination techniques. Eight PFTs were obtained from the functional classification of the species. The PFTs were dominated by C3 plants, particularly in high-altitude wetlands. The wetland plant communities in Lesotho exhibited the coexistence of species from different PFTs, highlighting functional differentiation to exploit microhabitat heterogeneity. Both functional traits and functional composition of communities were mainly influenced by altitude, longitude, slope and several edaphic factors. Because montane regions display greater sensitivity to changes in climate, alterations in wetland plant functional traits, PFTs and composition will possibly occur in the face of climate change. These alterations will result in modifications in montane wetland ecosystem functioning that include primary productivity and nutrient cycling, with subsequent changes in the delivery of ecosystem services.