Toward an understanding of broad-scale patterns of the habitat suitability of fountain grass (Cenchrus setaceus (Forssk.) Morrone, Poaceae)

Understanding the factors contributing to the introduction and spread of invasive species is crucial to help develop management strategies to control and eradicate them in sensitive areas. Our goals were to investigate (1) the association between habitat suitability of fountain grass (Cenchrus setaceus), human footprint, and environmental variables; (2) the biogeographical distribution of habitat suitability of fountain grass, an aggressive invasive species that has altered native ecosystems across multiple continents; (3) what kind of habitats are most likely to be invaded by fountain grass; and (4) the potential impact of climate change on the range of fountain grass. We showed that areas with the highest suitability are in desertic and xeric areas of the Mediterranean, and dry tropical, and subtropical bioclimates. The global biogeographic pattern of the suitability of fountain grass generally increases from the equator toward subtropical areas and then decreases at the north and south portions of the globe. Areas with the highest suitability occur along broad ecotonal zones between deserts and Mediterranean regions. Models indicated human footprint and annual mean temperature most contributed to explaining the global suitability patterns of fountain grass. Climate change analysis showed a high potential contraction of the potential range of fountain grass in the Mediterranean and tropical areas of the southwest USA, northern Mexico, northeast Brazil, and South Africa. Results also indicated a potential moderate expansion of its range, mainly in tropical areas of the southwest USA and East Africa. Our results give support for the tenet that anthropogenic factors and climate dynamics might be a strong explanation of the spatial distribution of fountain grass over broad-extent areas. Managers and stakeholders may apply our results to identify high-priority areas that can be used to prevent future invasions into areas of high suitability.