important for local livelihoods in the high-altitude communal grasslands in
South Africa, where other trees are rare. Acacia species provide fuelwood, which
is a primary source of heating and cooking fuel for almost all rural households
(de Neergaard et al. 2005; Shackleton et al. 2007; Aitken et al. 2009). Despite
increases in access to electricity in South Africa, Acacia dealbata (Silver Wattle)
is still highly important for livelihoods today with almost no change in use levels in
the past decade (Ngorima and Shackleton 2019). A number of households also earn
incomes from selling the wood. However, when they reach high densities, Acacia
species also have negative implications for water resources (Le Maitre et al. 2020,
Chap. 15), grazing (O’Connor and van Wilgen 2020, Chap. 16) and people’s health
and safety (Shackleton et al. 2018). In the relatively treeless Fynbos Biome, invasive
tree species are also an important source of fuelwood and income for rural villagers
and foresters (Kull et al. 2011). However, this is a fire-prone biome and Pinus
species can greatly increase the risk and negative implications of wild fires (Kraaij
et al. 2018), highlighting how ecological contexts can result in this unique disservice
(Comaroff and Comaroff 2001; Pooley 2014). Shackleton et al. (2015b) show that
most local stakeholders from the Karoo and Savanna Biomes prefer to use native
trees instead of the invasive Prosopis for fuelwood. In these areas, overall use of
Prosopis for fuelwood is declining with increasing access to and use of electricity,
unlike in the high-altitude Grassland Biome.
Research on Opuntia ficus-indica invasions in South Africa has provided insights
into the complex interaction between invasions and human wellbeing and how benefits
and costs are not static in time and space (Novoa et al. 2015a, b; Hill et al. 2020, Sect.
19.3; O’Connor and van Wilgen 2020, Sect. 16.5.5). Opuntia ficus-indica was promoted in arid areas to improve agricultural production (Beinart and Wotshela 2012),
and at first it greatly benefited commercial farmers and rural villagers (Beinart and
Wotshela 2003). Over time, it became invasive and spread over large areas, and its
negative impacts started to outweigh its benefits, leading to control measures to reduce
its spread, densities and negative impacts. Biological control was highly successful
and reduced its spread and population densities, leading to the lowering of costs and
the increase of benefits (Zimmermann and Moran 1991). Currently, with lower
densities, O. ficus-indica has been adopted into society and provides a number of
benefits for poor rural people, particularly through the collection and sale of fruits
(Shackleton et al. 2007, 2011), showing the important role of spatial and temporal
contexts.
Evidence from South Africa therefore supports this proposition and suggests that
the effects of biological invasions on people are influenced by specific social and
ecological contexts and can be highly dynamic in space and time. It highlights that in
some cases some actors benefit more than others or some impacts are more external
to people directly in contact with invasions (such as loss of water for cities
downstream).
24 The Social Dimensions of Biological Invasions in South Africa
713
South Africa, where other trees are rare. Acacia species provide fuelwood, which
is a primary source of heating and cooking fuel for almost all rural households
(de Neergaard et al. 2005; Shackleton et al. 2007; Aitken et al. 2009). Despite
increases in access to electricity in South Africa, Acacia dealbata (Silver Wattle)
is still highly important for livelihoods today with almost no change in use levels in
the past decade (Ngorima and Shackleton 2019). A number of households also earn
incomes from selling the wood. However, when they reach high densities, Acacia
species also have negative implications for water resources (Le Maitre et al. 2020,
Chap. 15), grazing (O’Connor and van Wilgen 2020, Chap. 16) and people’s health
and safety (Shackleton et al. 2018). In the relatively treeless Fynbos Biome, invasive
tree species are also an important source of fuelwood and income for rural villagers
and foresters (Kull et al. 2011). However, this is a fire-prone biome and Pinus
species can greatly increase the risk and negative implications of wild fires (Kraaij
et al. 2018), highlighting how ecological contexts can result in this unique disservice
(Comaroff and Comaroff 2001; Pooley 2014). Shackleton et al. (2015b) show that
most local stakeholders from the Karoo and Savanna Biomes prefer to use native
trees instead of the invasive Prosopis for fuelwood. In these areas, overall use of
Prosopis for fuelwood is declining with increasing access to and use of electricity,
unlike in the high-altitude Grassland Biome.
Research on Opuntia ficus-indica invasions in South Africa has provided insights
into the complex interaction between invasions and human wellbeing and how benefits
and costs are not static in time and space (Novoa et al. 2015a, b; Hill et al. 2020, Sect.
19.3; O’Connor and van Wilgen 2020, Sect. 16.5.5). Opuntia ficus-indica was promoted in arid areas to improve agricultural production (Beinart and Wotshela 2012),
and at first it greatly benefited commercial farmers and rural villagers (Beinart and
Wotshela 2003). Over time, it became invasive and spread over large areas, and its
negative impacts started to outweigh its benefits, leading to control measures to reduce
its spread, densities and negative impacts. Biological control was highly successful
and reduced its spread and population densities, leading to the lowering of costs and
the increase of benefits (Zimmermann and Moran 1991). Currently, with lower
densities, O. ficus-indica has been adopted into society and provides a number of
benefits for poor rural people, particularly through the collection and sale of fruits
(Shackleton et al. 2007, 2011), showing the important role of spatial and temporal
contexts.
Evidence from South Africa therefore supports this proposition and suggests that
the effects of biological invasions on people are influenced by specific social and
ecological contexts and can be highly dynamic in space and time. It highlights that in
some cases some actors benefit more than others or some impacts are more external
to people directly in contact with invasions (such as loss of water for cities
downstream).
24 The Social Dimensions of Biological Invasions in South Africa
713