Structural assemblages of plant species in the Owabi Ramsar Wetland in the Ashanti Region of Ghana

Abstract

Anthropogenic activities as predictors of species assemblages in the Owabi Ramsar Wetland were investigated between May and September 2019. Data were collected in 154 plots at five different sites. The prevalence index method was used to categorise the species into wetland and non-wetland indicators. Log series and Hill number models were applied to quantify community assemblages, whereas the CCA technique was used to examine the relationship between anthropogenic activities and species presence or absence. In all, 2 185 individuals, belonging to 32 families and 68 species were recorded. Paspalum orbiculare and Persicaria lanigera were the most abundant, indicating their wide distribution. Mean number of individuals were highest at Atafua and lowest at Owabi. An abundance of terrestrial species (41.2%; i.e. plant species not listed as obligate wetland plants) and facultative species (30.9%), compared with obligate wetland species (27.9%), suggests a dominance of species from dryland habitats into the wetland. Farming activities, increased levels of NH₄⁺, PO₄³⁺ and NO₃–N, were the predictors that explained 72.01% of the overall variability in community assemblages. The results revealed the impact of the anthropogenic activities on the ecological integrity of the Owabi Ramsar Wetland and the need to institute conservation measures outlined in this study.