Wilson JRU
Permanent URI for this collection
Browse
Browsing Wilson JRU by browse.metadata.type "Book Chapter"
Now showing 1 - 3 of 3
Results Per Page
Sort Options
- ItemThe biogeography of South African terrestrial plant invasions(Springer, Cham, 2020) Richardson, David M.; Foxcroft, Llewellyn C.; Latombe, Guillaume; Le Maitre, D.C.; Rouget, Mathieu; Wilson, John R.Thousands of plant species have been introduced, intentionally and accidentally, to South Africa from many parts of the world. Alien plants are now conspicuous features of many South African landscapes and hundreds of species have naturalised (i.e. reproduce regularly without human intervention), many of which are also invasive (i.e. have spread over long distances). There is no comprehensive inventory of alien, naturalised, and invasive plants for South Africa, but 327 plant taxa, most of which are invasive, are listed in national legislation. We collated records of 759 plant taxa in 126 families and 418 genera that have naturalised in natural and semi-natural ecosystems. Over half of these naturalised taxa are trees or shrubs, just under a tenth are in the families Fabaceae (73 taxa) and Asteraceae (64); genera with the most species are Eucalyptus, Acacia, and Opuntia. The southern African Plant Invaders Atlas (SAPIA) provides the best data for assessing the extent of invasions at the national scale. SAPIA data show that naturalised plants occur in 83% of quarter-degree grid cells in the country. While SAPIA data highlight general distribution patterns (high alien plant species richness in areas with high native plant species richness and around the main human settlements), an accurate, repeatable method for estimating the area invaded by plants is lacking. Introductions and dissemination of alien plants over more than three centuries, and invasions over at least 120 years (and especially in the last 50 years) have shaped the distribution of alien plants in South Africa. Distribution patterns of naturalised and invasive plants define four ecologically-meaningful clusters or “alien plant species assemblage zones”, each with signature alien plant taxa for which trait-environment interactions can be postulated as strong determinants of success. Some widespread invasive taxa occur in high frequencies across multiple zones; these taxa occur mainly in riparian zones and other azonal habitats, or depend on human-mediated disturbance, which weakens or overcomes the factors that determine specificity to any biogeographical region.
- ItemThe role of environmental factors in promoting and limiting biological invasions in South Africa(Springer, Cham., 2020) Wilson, John R.; Foxcroft, Llewellyn C.; Geerts, Sjirk; Hoffmann, M. Timm; MacFadyen, Sandra; Measey, John; Mills, Anthony; Richardson, David M.; Robertson, Mark P.; van Wilgen, Brian W.This chapter provides an overview of the researchers and research initiatives relevant to invasion science in South Africa over the past 130 years, profiling some of the more recent personalities, particularly those who are today regarded as international leaders in the field. A number of key points arise from this review. Since 1913, South Africa has been one of a few countries that have investigated and implemented alien plant biological control on a large scale, and is regarded as a leader in this field. South Africa was also prominent in the conceptualisation and execution of the international SCOPE project on the ecology of biological invasions in the 1980s, during which South African scientists established themselves as valuable contributors to the field. The development of invasion science benefitted from a deliberate strategy to promote multi-organisational, interdisciplinary research in the 1980s. Since 1995, the Working for Water programme has provided funding for research and a host of practical questions that required research solutions. Finally, the establishment of a national centre of excellence with a focus on biological invasions has made a considerable contribution to building human capacity in the field, resulting in advances in all aspects of invasion science—primarily in terms of biology and ecology, but also in history, sociology, economics and management. South Africa has punched well above its weight in developing the field of invasion science, possibly because of the remarkable biodiversity that provided a rich template on which to carry out research, and a small, well-connected research community that was encouraged to operate in a collaborative manner.
- ItemSouth Africa as a donor of naturalised and invasive plants to other parts of the world(SpringerOpen, 2020) Pysek, Petr; Pergl, Jan; van Kleunen, Mark; Dawson, Wayne; Essl, Franz; Kreft, Holger; Weigelt, Patrick; Wilson, John R.; Winter, Marten; Richardson, David M.This chapter provides the first assessment of South African native vascular plants as naturalised and invasive species in other parts of the world. For naturalised species, Global Naturalized Alien Flora (GloNAF) data were used, while for invasive species an assessment was made using the peer-reviewed literature, experience of the authors, and correspondence with authorities in many parts of the world. Results show that 1093 South African native plant taxa have been recorded as naturalised, but for only 79 of these is there strong and unequivocal evidence of invasiveness in natural or semi-natural ecosystems (another 132 taxa have been listed as invasive, but do not fulfil all criteria for listing as such). Thirty-five taxa have naturalised in more than 100 regions (countries, states, provinces, districts, or individual islands), and six taxa (all grasses—family Poaceae) are naturalised in more than 200 regions. However, of these, only 12 (34.2%) are recorded as invasive, and only nine fulfil the more conservative definition of invasive. These figures indicate that to be widely distributed does not automatically translate into being a strong invader, and that taxa that are extremely successful as invaders in some regions only succeed in specific environmental and geographic settings, and many of them are not widespread alien plants. Grasses are over-represented among both naturalised and invasive South African plant exports: 15% of naturalised species and 23% of invasive species are grasses. Temperate Asia and Europe are net donors of naturalised plants to South Africa, but Australasia and the Pacific Islands have received many more naturalised plants than they have donated to South Africa. Of taxa native to South Africa recorded as unequivocally invasive outside of cultivation elsewhere, 65% occur in Australia.