Combining natal range distributions and phylogeny to resolve biogeographic uncertainties in balloon vines (Cardiospermum, Sapindaceae)

Abstract

Aim A key aspect of effective invasive plant management is a clear understanding of natal ranges. In the balloon vine genus, Cardiospermum, uncertain native biogeographic ranges are hampering ongoing biological control efforts against invasive taxa in southern Africa. With the objective of minimizing non-target impacts, which are a major concern for conservation, we combine phylogenetic analyses with known native range distributions of selected Cardiospermum species to resolve unknown natal ranges for globally widespread balloon vines which occur in southern Africa.

Cardiospermum grandiflorum

“…Eight of these insects displayed wider host ranges, capable of feeding and developing on other cosmopolitan Cardiospermum species in South Africa, in particular C. halicacabum and C. corindum . This is problematic for the region because, while both C. grandiflorum and C. halicacabum are non‐native in South Africa, C. corindum is considered native (Gildenhuys et al ., ,b). Of those potential biological control agents tested to date, most were largely restricted to its taxonomic family (Sapindaceae) or genus, but not necessarily to the species Cardiospermum grandiflorum .…”

From the Neotropics to the Namib: evidence for rapid ecological divergence following extreme long-distance dispersal

“…Some New World C. corindum populations are also found in arid regions such as the Sonoran Desert (S Carroll, personal observation). African C. corindum from southern Africa appears phylogenetically more closely related to the Namib Desert endemic, C. pechuelii Kuntze, than to South American C. corindum , despite its morphological resemblance to the latter (Gildenhuys et al ., ). This paraphyletic grouping of C. corindum is peculiar given that C. pechuelii is distinct from African C. corindum based on morphology and habitat requirements (Fig.…”

“…The genus Cardiospermum (17 species), commonly known as balloon vines, are mostly restricted to the Neotropics with a few exceptions (Gildenhuys et al ., ). Numerous species have also been introduced globally to areas where they are now considered invasive (Gildenhuys et al ., , ). For example, in southern Africa C. grandiflorum Sw. and C. halicacabum L. are thought to be introduced from South America and invasive, whereas C. corindum L. is regarded as native to both southern Africa and South America (Gildenhuys et al ., ).…”

“…Numerous species have also been introduced globally to areas where they are now considered invasive (Gildenhuys et al ., , ). For example, in southern Africa C. grandiflorum Sw. and C. halicacabum L. are thought to be introduced from South America and invasive, whereas C. corindum L. is regarded as native to both southern Africa and South America (Gildenhuys et al ., ). A phylogenetic treatment of the group suggests that the latter represents an extreme long‐distance dispersal event from South America to southern Africa, which occurred between 5.9 and 15.1 Ma (Gildenhuys et al ., ).…”

“…Here, expanding on a previous study on the biogeography of selected Cardiospermum spp. (Gildenhuys et al ., ), we aim to better understand the historic relationships between C. pechuelii and C. corindum using phylogenetic and population genetic approaches. This will allow us to elucidate the dynamics of diversification following intercontinental long‐distance dispersal.…”