Biological Invasions in South Africa’s Urban Ecosystems: Patterns, Processes, Impacts, and Management

Potgieter, Luke J.; Douwes, Errol; Gaertner, Mirijam; Measey, John; Paap, T.; Richardson, David M.

doi:10.1007/978-3-030-32394-3_11

Cited by 33 publications

(30 citation statements)

References 131 publications

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“…Ogden et al 2019). The remaining chapters focus on specific areas that are invaded-freshwater ecosystems (Weyl et al 2020), coastal marine ecosystems (Robinson et al 2020), offshore sub-Antarctic islands (Greve et al 2020), and urban settings (Potgieter et al 2020). Most invasive alien species in South Africa are plants (Table 1.1), and these are consequently best understood.…”

Section: Scope and Arrangement Of This Bookmentioning

confidence: 99%

Biological Invasions in South Africa: An Overview

Wilgen

Measey

Richardson

et al. 2020

Biological Invasions in South Africa

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101

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South Africa has much to offer as a location for the study of biological invasions. It is an ecologically diverse country comprised of nine distinct terrestrial biomes, four recognised marine ecoregions, and two sub-Antarctic Islands. The country has a rich and chequered socio-political history, and a similarly varied history of species introductions. There has been a long tradition of large-scale conservation in the country, and efforts to manage and regulate invasions began in the nineteenth century, with some notable successes, but many setbacks. With the advent of democracy in the early 1990s, South Africa established large alien species control programmes to meet the dual demands of poverty alleviation and conservation, and has since pioneered regulatory approaches to address invasions. In terms of research, South Africa has played an important role in the development of invasion science globally. It continues to have one of the most active communities anywhere in the world, with strengths in theoretical and applied invasion science, and world-leading expertise in specific sub-disciplines (e.g. the classical biological control of invasive plants). In this introductory chapter to the book "Biological Invasions in South Africa", we highlight key events that have affected biological invasions, their management, and the research conducted over the past two centuries. In so doing, we build on earlier reviews-from a national situational review of the state of knowledge in

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Section: Scope and Arrangement Of This Bookmentioning

confidence: 99%

Biological Invasions in South Africa: An Overview

Wilgen

Measey

Richardson

et al. 2020

Biological Invasions in South Africa

Self Cite

101

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“…11). Sus scrofa damages some critically endangered plants in the Western Cape, affecting succession and facilitating alien plant spread (Picker and Griffiths 2011). Capra hircus grazing has reduced the cover and density of endemic geophytes and succulents shrubs in thicket vegetation, and conservation of this endemic-rich flora is seriously threatened (Moolman and Cowling 1994).…”

Section: Mammalsmentioning

confidence: 99%

An Evaluation of the Impacts of Alien Species on Biodiversity in South Africa Using Different Assessment Methods

Zengeya

Kumschick

Weyl

et al. 2020

Biological Invasions in South Africa

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Studies of the impact of alien species on the environment are increasingly being carried out, and there has been ongoing debate about how to standardise the description of these impacts. This chapter evaluates the state of knowledge on the impacts of alien species on biodiversity in South Africa based on different assessment methods. Despite South Africa being one of the most biologically diverse countries in the world, there have been very few studies that formally document the impacts of alien species on biodiversity. Most of what is known is based on expert opinion, and consequently the level of confidence in the estimates of the magnitude of these impacts is low. However, it is clear that a significant number of alien species cause major negative impacts, and that there is cause for serious concern. There is a

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“…A co-ordinated strategy to deal with PSHB in South Africa will require a revision of legislation and the creation of policies pertaining to biological invasions. Currently, there is no co-ordinated management of invaders in urban ecosystems (Potgieter et al 2020), a critical oversight as shown in this study. The governance of IAS in general, and PSHB in particular, would require re-alignment of priorities between various spheres of government and enhanced involvement of private actors.…”

Section: Discussionmentioning

confidence: 90%

“…Given that the invasion in South Africa is at an early stage, very little is known about both its current and possible unmitigated spread and impact. As has been the case in other parts of the world (Gaertner et al 2017), little attention has been paid to assessing the impacts of biological invasions in urban ecosystems of South Africa (Potgieter et al 2020). One source estimates that if all of Johannesburg's 10 million urban trees are affected, it may have an impact of over R50bn if these trees need to be removed, chopped, chipped and replanted with more resistant species (DAFF 2020a).…”

Section: Introductionmentioning

confidence: 99%

Invasion of the Polyphagous Shot Hole Borer Beetle in South Africa A Preliminary Assessment of the Economic Impacts

Crookes

Blignaut

et al. 2021

Preprint

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Few economic assessments have been developed to inform national priorities on the management of high-impact, early-stage invasive alien species (IAS). Economic assessments are biased towards ex post assessments of the costs and benefits of control options and are in need of refinement to deal with potentially vigorous invaders with considerable uncertainty on spread and impact. The Polyphagous Shot Hole Borer (PSHB) beetle represents a potentially high-impact invasion in progress in South Africa. We approached the problem of PSHB invasion in South Africa through (i) interdisciplinary collaboration to reduce uncertainty in economic and biological parameters by defining robust ranges for model parameters and (ii) a simulation model to take account of dynamic mutualistic relations between the beetle and it’s symbiont fungus. We modelled the potential social cost of a PSHB invasion on natural forests, urban trees, commercial forestry and the avocado industry. Our results indicate that the unmitigated baseline present social cost of $27.12bn in the case of a PSHB invasion in South Africa is in the order of 1% of the country’s GDP, or expressed differently at around $50 per year per South African citizen (10-year modelling horizon using a discount rate of 6%). Most of the social costs in our model are for the removal of urban trees that die as a result of the PSHB, a result that corroborates well with findings in other regions where PSHB has invaded. We conclude that an ex ante economic assessment system dynamics model can effectively inform national strategies on IAS management. The disproportionately high impacts of a PSHB invasion on municipalities and private actors demands a revision of legislation and creation of policies pertaining to the management of biological invasions in South Africa.

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Biological Invasions in South Africa’s Urban Ecosystems: Patterns, Processes, Impacts, and Management

Cited by 33 publications

References 131 publications

Biological Invasions in South Africa: An Overview

Biological Invasions in South Africa: An Overview

An Evaluation of the Impacts of Alien Species on Biodiversity in South Africa Using Different Assessment Methods

Invasion of the Polyphagous Shot Hole Borer Beetle in South Africa A Preliminary Assessment of the Economic Impacts

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