1986, culminating most recently with a comprehensive report on the status of
biological invasions and their management at a national level in 2018.
Our book comprises 31 chapters (including this one), divided into seven parts that
examine where we have come from, where we are, how we got here, why the issue is
important, what we are doing about it, what we have learnt, and where we may be headed.
The book lists over 1400 alien species that have established outside of captivity or
cultivation. These species cost the country at least US$1 billion per year (~ZAR
15 billion), and threaten South Africa’s unique biodiversity. The introduction and
spread of alien species, the impacts that they have had, the benefits that they have
brought, and the attempts to manage them have provided many opportunities for
research. Documenting what we have learned from this unplanned experiment is a
primary goal of this book. We hope this book will allow readers to better understand
biological invasions in South Africa, and thereby assist them in responding to the
challenge of addressing the problem.
1.1 Why South Africa Is an Interesting Place for Biological
Invasions?
South Africa has a rich and varied biodiversity, and a long history of alien species
introductions that took place within the context of a complex socio-political environment. South Africa also has a long history of conservation management, as well
as a history of regulating and managing biological invasions. Research specifically
on biological invasions goes back at least five decades. In this section we review
these factors, and argue that, as a result of them, South Africa is a particularly
interesting place to study the phenomenon of biological invasions (Fig. 1.1).
1.1.1 A Rich and Varied Biodiversity
South Africa, covering only 0.8% of the earth’s terrestrial area, is one of the planet’s
18 “megadiverse countries”, defined by Conservation International as nations that
harbour the majority of Earth’s species and high numbers of endemic species. It is
home to 23,420 described terrestrial plant species (~6% of the global total; Willis
2017), ~60,000 terrestrial and freshwater invertebrate species (~1% of the global
total), 3107 vertebrate species (~6.5% of the global total), 12,000 coastal marine
species (~15% of the global total; Le Roux 2002; Griffiths et al. 2010), and ~1.8% of
the world’s described soil species (Janion-Scheepers et al. 2016)]. 60% of
South Africa’s terrestrial plants and 70% of its terrestrial and freshwater invertebrates are endemic (Le Roux 2002).
This diversity is partly due to the wide variety of environmental conditions
(Wilson et al. 2020a, Chap. 13) that have resulted in continental South Africa’s
nine terrestrial biomes, ranging from desert to rainforest (Mucina and Rutherford
2006; Fig. 1.2). There are also four recognised marine ecoregions in South Africa
4
B. W. van Wilgen et al.
biological invasions and their management at a national level in 2018.
Our book comprises 31 chapters (including this one), divided into seven parts that
examine where we have come from, where we are, how we got here, why the issue is
important, what we are doing about it, what we have learnt, and where we may be headed.
The book lists over 1400 alien species that have established outside of captivity or
cultivation. These species cost the country at least US$1 billion per year (~ZAR
15 billion), and threaten South Africa’s unique biodiversity. The introduction and
spread of alien species, the impacts that they have had, the benefits that they have
brought, and the attempts to manage them have provided many opportunities for
research. Documenting what we have learned from this unplanned experiment is a
primary goal of this book. We hope this book will allow readers to better understand
biological invasions in South Africa, and thereby assist them in responding to the
challenge of addressing the problem.
1.1 Why South Africa Is an Interesting Place for Biological
Invasions?
South Africa has a rich and varied biodiversity, and a long history of alien species
introductions that took place within the context of a complex socio-political environment. South Africa also has a long history of conservation management, as well
as a history of regulating and managing biological invasions. Research specifically
on biological invasions goes back at least five decades. In this section we review
these factors, and argue that, as a result of them, South Africa is a particularly
interesting place to study the phenomenon of biological invasions (Fig. 1.1).
1.1.1 A Rich and Varied Biodiversity
South Africa, covering only 0.8% of the earth’s terrestrial area, is one of the planet’s
18 “megadiverse countries”, defined by Conservation International as nations that
harbour the majority of Earth’s species and high numbers of endemic species. It is
home to 23,420 described terrestrial plant species (~6% of the global total; Willis
2017), ~60,000 terrestrial and freshwater invertebrate species (~1% of the global
total), 3107 vertebrate species (~6.5% of the global total), 12,000 coastal marine
species (~15% of the global total; Le Roux 2002; Griffiths et al. 2010), and ~1.8% of
the world’s described soil species (Janion-Scheepers et al. 2016)]. 60% of
South Africa’s terrestrial plants and 70% of its terrestrial and freshwater invertebrates are endemic (Le Roux 2002).
This diversity is partly due to the wide variety of environmental conditions
(Wilson et al. 2020a, Chap. 13) that have resulted in continental South Africa’s
nine terrestrial biomes, ranging from desert to rainforest (Mucina and Rutherford
2006; Fig. 1.2). There are also four recognised marine ecoregions in South Africa
4
B. W. van Wilgen et al.