taxa have also been accidentally introduced, or have spread unaided into the country
from neighbouring countries where they have previously been introduced. Similar to
other regions, organisms of different types have been introduced to South Africa
through different pathways, and some pathways have introduced more taxa that have
become invasive than others. Changing socio-economic factors have played an
important role in shaping the pathways of introduction and dispersal for
South Africa. The first known introductions to South Africa were mostly intentional
introductions from Africa for agriculture and medicine. However, as a result of
increasing and geographically expanding trade and transport, the development of
new technologies, and changing human interests and attitudes, over time, new
pathways of introduction and dispersal developed, and the importance of existing
pathways changed. Control measures have been put in place to manage some of the
pathways, but despite these measures introductions continue to occur at an increasing
rate. It is likely that these trends will persist into the future, and in particular, accidental
introductions are likely to increase with increasing trade. Due to new legislation, the
risks posed by legal intentional introductions should be reduced, but technological and
political developments mean that it is becoming increasingly difficult to manage the
pathways and enforce existing regulations. To better inform management, further
research into the pathways of introduction and dispersal is required.
12.1 Introduction
Since the 1500s there has been a dramatic increase in the volume of goods and the
number of people being moved around the world (Harrari 2015). Consequently, there
has been, and continues to be, an increase in the number of organisms being
transported and introduced to regions where they are not native (Hulme 2009; Seebens
et al. 2017). Pathways of introduction are the processes that lead to the movement of
alien taxa from one geographical location to another (Richardson et al. 2011), and
include both the vector on or within which the organism is transported (e.g. ship,
aeroplane) and the route followed (Essl et al. 2015). These pathways not only facilitate
the movement of alien taxa between countries, but also the transportation of taxa
D. L. Saccaggi
Plant Health Diagnostic Services, Directorate: Inspection Services, Department of Agriculture,
Land Reform and Rural Development, Stellenbosch, South Africa
O. L. F. Weyl
DSI-NRF South African Research Chair in Inland Fisheries and Freshwater Ecology,
South African Institute for Aquatic Biodiversity, Makhanda, South Africa
Centre for Invasion Biology, South African Institute for Aquatic Biodiversity, Makhanda,
South Africa
V. L. Williams
School of Animal, Plant and Environmental Sciences, University of the Witwatersrand,
Johannesburg, South Africa
314
K. T. Faulkner et al.
from neighbouring countries where they have previously been introduced. Similar to
other regions, organisms of different types have been introduced to South Africa
through different pathways, and some pathways have introduced more taxa that have
become invasive than others. Changing socio-economic factors have played an
important role in shaping the pathways of introduction and dispersal for
South Africa. The first known introductions to South Africa were mostly intentional
introductions from Africa for agriculture and medicine. However, as a result of
increasing and geographically expanding trade and transport, the development of
new technologies, and changing human interests and attitudes, over time, new
pathways of introduction and dispersal developed, and the importance of existing
pathways changed. Control measures have been put in place to manage some of the
pathways, but despite these measures introductions continue to occur at an increasing
rate. It is likely that these trends will persist into the future, and in particular, accidental
introductions are likely to increase with increasing trade. Due to new legislation, the
risks posed by legal intentional introductions should be reduced, but technological and
political developments mean that it is becoming increasingly difficult to manage the
pathways and enforce existing regulations. To better inform management, further
research into the pathways of introduction and dispersal is required.
12.1 Introduction
Since the 1500s there has been a dramatic increase in the volume of goods and the
number of people being moved around the world (Harrari 2015). Consequently, there
has been, and continues to be, an increase in the number of organisms being
transported and introduced to regions where they are not native (Hulme 2009; Seebens
et al. 2017). Pathways of introduction are the processes that lead to the movement of
alien taxa from one geographical location to another (Richardson et al. 2011), and
include both the vector on or within which the organism is transported (e.g. ship,
aeroplane) and the route followed (Essl et al. 2015). These pathways not only facilitate
the movement of alien taxa between countries, but also the transportation of taxa
D. L. Saccaggi
Plant Health Diagnostic Services, Directorate: Inspection Services, Department of Agriculture,
Land Reform and Rural Development, Stellenbosch, South Africa
O. L. F. Weyl
DSI-NRF South African Research Chair in Inland Fisheries and Freshwater Ecology,
South African Institute for Aquatic Biodiversity, Makhanda, South Africa
Centre for Invasion Biology, South African Institute for Aquatic Biodiversity, Makhanda,
South Africa
V. L. Williams
School of Animal, Plant and Environmental Sciences, University of the Witwatersrand,
Johannesburg, South Africa
314
K. T. Faulkner et al.