Ecological niche modelling and ordination techniques highlight the high invasive potential of pompom weed (Campuloclinium macrocephalum, Asteraceae) in Africa

The assessments of the status of biological invasions and the implementation of mitigation strategies to reduce their detrimental effects on biodiversity represent current challenges for invasion ecology and management. The analysis of niche dynamics provides an effective tool for predicting the invasive potential of alien species, their capacity to thrive and expand and, consequently, for anticipating where they may have detrimental effects. Campuloclinium macrocephalum (Asteraceae) is a perennial herb native to Mexico, Central America, and South America. The species was introduced into South Africa, where it was initially established in disturbed sites such as roadsides. Subsequently, it invaded natural grasslands, open savannahs and wetlands, displacing native species. In this study, we evaluate the consistency between the niche in the native and invaded ranges of C. macrocephalum, considering climatic and edaphic variables, and using two approaches: ordination techniques and ecological niche modelling, including reciprocal niche modelling. The results of the niche equivalency and similarity tests, in conjunction with the high niche stability observed in the invaded range, indicate that C. macrocephalum exhibits niche conservatism. The modelling and the high values of unoccupied niche revealed a significant potential for further expansion in the invaded range, towards new areas especially in the south and southwestern region of South Africa, and the centre of the Republic of Angola. Consequently, it is crucial to focus attention on these areas to anticipate possible future invasions. These findings provide support for the use of ecological niche models to predict the risk of invasion and the responses to climate change of C. macrocephalum.