Comparison of the floodplain forest floristic composition of two riparian corridors: species richness, alien species and the effect of water regime changes

Abstract

AbstractFloodplain forests are sensitive to changes within the surrounding environment and contain the most highly invaded habitats. The overall aim of this study was to characterise floristic composition of floodplain forest along two different riparian corridors. The studied river ecosystems were influenced by human disturbances, but they have historically different hydrological management practices (e.g., damming and water regime management). We hypothesised that different hydrological management practices affect the composition and diversity of vegetation and influence multiple ecosystem functions and services in floodplain forests. A detailed study of the vascular plant species diversity of floodplain forests in the lower parts of two riparian corridors of the Thaya and Morava Rivers (South Moravia) was conducted. Altogether, 853 species of vascular plants were recorded, including 121 species of woody plants. We found 111 species that are protected by law or threatened according to the Czech Red List. We found 230 alien species, out of which 125 are archaeophytes and 105 are neophytes. Thirty-nine species are invasive; however, the most frequent group comprises naturalised archaeophytes (78). Differences in the effects of environmental factors on species richness and the proportions of alien and endangered species were tested using generalised linear models (GLMs). Differences in species composition in the two distinct riparian corridors were examined using non-metric multidimensional scaling (NMDS). Although only small differences were observed in the vegetation composition, we observed some differences in species richness and species composition between the riparian corridors. The most obvious difference was a higher proportion of alien species in the Morava River corridor than in the Thaya River corridor. In contrast, the proportion of endangered species richness was higher in the Thaya River corridor. We assume that the most probable explanation of the differences is the unique water management history for each river corridor.