The response of 6 alien invasive plant species to spatiotemporal variations in water availability in Hluhluwe iMfolozi park

Abstract

Humans are one of the largest contributors to current global biological invasions, spreading species across the globe. Biological invasions are characterized by species being transported from their native range to new locations, where they start to spread uncontrollably due to both biotic and abiotic drivers. The impacts of biological invasions in South Africa are not limited to issues regarding ecological degradation, but also inflict economic implications and water scarcity problems. In HiP 6 species are identified as the most widely spread alien invasive species: Chromolaena odorata, Parthenium hysterophorus, Lantana camara, Tagetes minuta Opuntia ficus-indica, and Opuntia aurantiaca. The invasive species have different strategies when it comes to coping with water availability. The aim of this study is to monitor the distribution and density of 6 alien invasive plant species in HiP, and to increase our understanding on how climate change affects the alien invasive plants in regard to their strategy, in terms of variability in spatial and temporal water availability. We found that all the observerd alien invasive species have significantly increased in 2019. Also, that most of the invasive species are found in Manzibomvu, the section with the most rainfall. These findings seem to agree with the trends in spatial and temporal water availability. They also seem to relate to the practises of the WfW programme, notably the hold up of it in 2016, especially for C. odorata. C. odorata has increased the most in 2019 and is still the most abundant invasive species in HiP.