Browsing by Author "Carroll, Scott P."

Now showing 1 - 2 of 2
  • Thumbnail Image
    Item
    The ecology, biogeography, history and future of two globally important weeds : Cardiospermum halicacabum Linn. and C. grandiflorum Sw.
    (Pensoft, 2013-10-11) Gildenhuys, Enelge; Ellis, Allan G.; Carroll, Scott P.; Le Roux, Johannes J.
    Members of the balloon vine genus, Cardiospermum, have been extensively moved around the globe as medicinal and horticultural species, two of which are now widespread invasive species; Cardiospermum grandiflorum and Cardiospermum halicacabum. A third species, Cardiospermum corindum, may also have significant invasion potential. However, in some regions the native status of these species is not clear, hampering management. For example, in South Africa it is unknown whether Cardiospermum halicacabum and Cardiospermum corindum are native, and this is a major constraint to on-going biological control programmes against invasive Cardiospermum grandiflorum. We review the geography, biology and ecology of selected members of the genus with an emphasis on the two most widespread invaders, Cardiospermum halicacabum and Cardiospermum grandiflorum. Specifically, we use molecular data to reconstruct a phylogeny of the group in order to shed light on the native ranges of Cardiospermum halicacabum and Cardiospermum corindum in southern Africa. Phylogenetic analyses indicate that southern African accessions of these species are closely related to South American taxa indicating human-mediated introduction and/or natural long distance dispersal. Then, on a global scale we use species distribution modelling to predict potential suitable climate regions where these species are currently absent. Native range data were used to test the accuracy with which bioclimatic modelling can identify the known invasive ranges of these species. Results show that Cardiospermum species have potential to spread further in already invaded or introduced regions in Australia, Africa and Asia, underlining the importance of resolving taxonomic uncertainties for future management efforts. Bioclimatic modelling predicts Australia to have highly favourable environmental conditions for Cardiospermum corindum and therefore vigilance against this species should be high. Species distribution modelling showed that native range data over fit predicted suitable ranges, and that factors other than climate influence establishment potential. This review opens the door to better understand the global biogeography of the genus Cardiospermum, with direct implications for management, while also highlighting gaps in current research.
  • Thumbnail Image
    Item
    The potential evolutionary impact of invasive balloon vines on native soapberry bugs in South Africa
    (Pensoft Publishers, 2019-07-25) Foster, Jarryd D.; Ellis, Allan G.; Foxcroft, Llewellyn C.; Carroll, Scott P.; Le Roux, Johannes
    Following their establishment in new communities, invasive species may cause evolutionary changes in resident native species. This is clearly true for phytophagous insects, which may adapt rapidly when utilising abundant and widespread introduced hosts. The balloon vines Cardiospermum halicacabum and C. grandiflorum were introduced to South Africa approximately 100 years ago and are classified as minor and major weeds, respectively. Here we assess the potential evolutionary impact of these vines on native Leptocoris soapberry bug populations in Kruger National Park (KNP), using phylogenetic and morphometric analyses. We found that soapberry bugs associated with C. halicacabum are genetically and morphologically distinct from those associated with C. grandiflorum. This suggests that native soapberry bugs in KNP exhibit some degree of host preference, indicating that these vines may have had significant evolutionary consequences for these insects. The proboscis length of soapberry bugs feeding on C. halicacabum closely matched fruit size, often being longer than fruit size at the population level. These soapberry bugs are therefore well-suited to feeding on this introduced plant species.