24.4.2 Proposition 3b: Social Science Research on Invasive
Species Primarily Focuses on Negative Effects
of Invasive Alien Species for People
Traditionally, ecological research on biological invasions has focussed on negative
effects and ignored benefits of invasive species (Tassin and Kull 2015), and therefore
we expect that to be similar in the social sciences and humanities.
Unlike ecological studies, two studies in South Africa discussed only the positive
aspects of invasive species for local livelihoods and ignored any negative effects.
Shackleton et al. (2011) showed the importance of selling O. ficus-indica fruits in
rural areas of the Eastern Cape. In the same region the invasive fish Cyprinus carpio
(Common Carp) benefits livelihoods, as a source of both food and cash income from
the sale of fish (Ellender et al. 2010)—as yet no negative livelihood effects have been
investigated from this introduction.
Most other studies acknowledge a suite of benefits and costs and often weigh
them against each other. For example, the benefits of O. ficus-indica and Australian
Acacia species were viewed as greater than the costs to rural communal land
villagers (de Neergaard et al. 2005; Shackleton et al. 2007; Beinart and Wotshela
2012)—although some costs were highlighted as well. For Prosopis, both benefits
and costs were assessed, and findings indicated that negative impacts outweighed
benefits (Wise et al. 2012; Shackleton et al. 2015a). Potgieter et al. (2019) showed
that many urban invasives provide both ecosystem services and disservices to
people, as is the case for small rural villages in the Kalahari (Shackleton and
Shackleton 2018). Harris et al. (2016) argued that work on Columba spp. (Pigeons)
has traditionally focused on negative issues and control, but their research actually
showed the opposite—that people on the University of South Africa’s Muckleneuk
campus would rather encourage Pigeons.
On a commercial level, the invasive Mediterranean Mussel (Mytilus
galloprovincialis) is an important aquaculture species in South Africa and benefits
are acknowledged (Hecht 1992). Similarly, invasive trees used in forestry provide
financial benefits and employment (Tewari 2001; Louw 2004; Bennett and Kruger
2015). At the same time, they have negative implications for other livelihood
activities and broader society (Le Maitre et al. 2011). For these kinds of species,
economic research commonly applies cost-benefit analyses to estimate both positive
and negative impacts (de Wit et al. 2001) and better understand conflicts and tradeoffs (van Wilgen and Richardson 2014; Zengeya et al. 2017).
Research that has examined the social effects of invasive species in South Africa
is fairly balanced and reports on both positive and negative impacts. This is contrary
to our proposition. This also differs substantially from ecological research that tends
to focus only on the negative implications (Tassin and Kull 2015). There are many
invasive species globally that have mostly negative impacts and a lot of work
elsewhere focuses on reporting and quantifying just these negative social effects as
opposed to more balanced views (Shackleton et al. 2019c).
714
R. T. Shackleton et al.
Species Primarily Focuses on Negative Effects
of Invasive Alien Species for People
Traditionally, ecological research on biological invasions has focussed on negative
effects and ignored benefits of invasive species (Tassin and Kull 2015), and therefore
we expect that to be similar in the social sciences and humanities.
Unlike ecological studies, two studies in South Africa discussed only the positive
aspects of invasive species for local livelihoods and ignored any negative effects.
Shackleton et al. (2011) showed the importance of selling O. ficus-indica fruits in
rural areas of the Eastern Cape. In the same region the invasive fish Cyprinus carpio
(Common Carp) benefits livelihoods, as a source of both food and cash income from
the sale of fish (Ellender et al. 2010)—as yet no negative livelihood effects have been
investigated from this introduction.
Most other studies acknowledge a suite of benefits and costs and often weigh
them against each other. For example, the benefits of O. ficus-indica and Australian
Acacia species were viewed as greater than the costs to rural communal land
villagers (de Neergaard et al. 2005; Shackleton et al. 2007; Beinart and Wotshela
2012)—although some costs were highlighted as well. For Prosopis, both benefits
and costs were assessed, and findings indicated that negative impacts outweighed
benefits (Wise et al. 2012; Shackleton et al. 2015a). Potgieter et al. (2019) showed
that many urban invasives provide both ecosystem services and disservices to
people, as is the case for small rural villages in the Kalahari (Shackleton and
Shackleton 2018). Harris et al. (2016) argued that work on Columba spp. (Pigeons)
has traditionally focused on negative issues and control, but their research actually
showed the opposite—that people on the University of South Africa’s Muckleneuk
campus would rather encourage Pigeons.
On a commercial level, the invasive Mediterranean Mussel (Mytilus
galloprovincialis) is an important aquaculture species in South Africa and benefits
are acknowledged (Hecht 1992). Similarly, invasive trees used in forestry provide
financial benefits and employment (Tewari 2001; Louw 2004; Bennett and Kruger
2015). At the same time, they have negative implications for other livelihood
activities and broader society (Le Maitre et al. 2011). For these kinds of species,
economic research commonly applies cost-benefit analyses to estimate both positive
and negative impacts (de Wit et al. 2001) and better understand conflicts and tradeoffs (van Wilgen and Richardson 2014; Zengeya et al. 2017).
Research that has examined the social effects of invasive species in South Africa
is fairly balanced and reports on both positive and negative impacts. This is contrary
to our proposition. This also differs substantially from ecological research that tends
to focus only on the negative implications (Tassin and Kull 2015). There are many
invasive species globally that have mostly negative impacts and a lot of work
elsewhere focuses on reporting and quantifying just these negative social effects as
opposed to more balanced views (Shackleton et al. 2019c).
714
R. T. Shackleton et al.