aided the invasion of frogs in South Africa (Davies et al. 2013; Measey et al. 2017).
Similarly, the distribution of the invasive bird Acridotheres tristus (Common Myna)
in South Africa is closely tied to large urban areas (Peacock et al. 2007; Measey et al.
2020, Chap. 5). Environmental degradation and land use change also affects invasions (Kueffer 2017). In South Africa, overstocking of domestic livestock helped
Opuntia ficus-indica (Mission Prickly Pear) to become a dominant in the Eastern
Cape—“farmers became increasingly aware of their own hand in the gradual
transformation of the landscape around them, so opuntia intruded from the margins
to the centre” (van Sittert 2002). In the marine context, Carcinus maenas (Green
Crab) has established and become invasive only in human-made harbours and small
bays nearby because the species cannot maintain a grip on rocks under high wave
action (Mabin et al. 2017). In South Africa one of the 26 inter-basin transfer schemes
(i.e. channels or tunnels constructed to link different river systems) has aided the
spread of at least five non-native species (Ellender et al. 2014).
These few examples show that human modifications of species and landscapes
can facilitate invasions, supporting our proposition. This shows some support to the
“passenger” part of the driver vs passenger debate—whereby degradation might
facilitate invasions rather than invasions causing initial degradation. Despite this, a
lot more work can be done on how human modifications facilitate invasions and
maybe incorporating this more into models would be useful (e.g. niche modelling,
Vimercati et al. 2017; Walker et al. 2017).
24.3 People’s Conceptulisation and Perceptions of Invasive
Alien Species
A fast-growing body of literature in the field of invasion science considers how
people view and conceptualise invasive species, both from a theoretical level to more
of a personal and individual level (Kull et al. 2011, 2019; Estévez et al. 2015;
Shackleton et al. 2019b). South Africa provides a fertile testing ground for different
theories within this topic due to its diverse social and ecological contexts.
24.3.1 Proposition 2a: How People Think About, Value
and Study Invasive Species is Strongly Shaped by
Social-ecological Contexts
Historical, geographical, ecological, social and institutional contexts help to determine how people think about invasive species. For instance, attention to biological
invasions is weak in South America (Speziale et al. 2012), whereas in colonial island
landscapes, settings of rapid ecological change caused by the settlers as well as
strong scientific interest by the same people, environmental concerns rose to the fore
(Grove 1995). Such influence is also apparent in South Africa, where concern over
708
R. T. Shackleton et al.
Similarly, the distribution of the invasive bird Acridotheres tristus (Common Myna)
in South Africa is closely tied to large urban areas (Peacock et al. 2007; Measey et al.
2020, Chap. 5). Environmental degradation and land use change also affects invasions (Kueffer 2017). In South Africa, overstocking of domestic livestock helped
Opuntia ficus-indica (Mission Prickly Pear) to become a dominant in the Eastern
Cape—“farmers became increasingly aware of their own hand in the gradual
transformation of the landscape around them, so opuntia intruded from the margins
to the centre” (van Sittert 2002). In the marine context, Carcinus maenas (Green
Crab) has established and become invasive only in human-made harbours and small
bays nearby because the species cannot maintain a grip on rocks under high wave
action (Mabin et al. 2017). In South Africa one of the 26 inter-basin transfer schemes
(i.e. channels or tunnels constructed to link different river systems) has aided the
spread of at least five non-native species (Ellender et al. 2014).
These few examples show that human modifications of species and landscapes
can facilitate invasions, supporting our proposition. This shows some support to the
“passenger” part of the driver vs passenger debate—whereby degradation might
facilitate invasions rather than invasions causing initial degradation. Despite this, a
lot more work can be done on how human modifications facilitate invasions and
maybe incorporating this more into models would be useful (e.g. niche modelling,
Vimercati et al. 2017; Walker et al. 2017).
24.3 People’s Conceptulisation and Perceptions of Invasive
Alien Species
A fast-growing body of literature in the field of invasion science considers how
people view and conceptualise invasive species, both from a theoretical level to more
of a personal and individual level (Kull et al. 2011, 2019; Estévez et al. 2015;
Shackleton et al. 2019b). South Africa provides a fertile testing ground for different
theories within this topic due to its diverse social and ecological contexts.
24.3.1 Proposition 2a: How People Think About, Value
and Study Invasive Species is Strongly Shaped by
Social-ecological Contexts
Historical, geographical, ecological, social and institutional contexts help to determine how people think about invasive species. For instance, attention to biological
invasions is weak in South America (Speziale et al. 2012), whereas in colonial island
landscapes, settings of rapid ecological change caused by the settlers as well as
strong scientific interest by the same people, environmental concerns rose to the fore
(Grove 1995). Such influence is also apparent in South Africa, where concern over
708
R. T. Shackleton et al.