areas increasingly hinge on the contributions of invasive species to deliver ES and
EDS (Potgieter et al. 2017; Vaz et al. 2017). Decisions must be made on whether to
manage to enhance ES provision, or to minimise EDS. Such decisions are largely
context-specific, and managers need to consider the knock-on effects when reducing
EDS or enhancing specific ES, as other ES may be indirectly disrupted, or novel
EDS created. Decisions need to be transparent and must consider opinions of a wide
range of stakeholders including the public and those involved in urban land-use and
ecosystem management decisions (Novoa et al. 2018). Furthermore, a variety of
approaches (e.g. citizen science, remote sensing, and active surveillance) are needed
to determine the distribution patterns of native and alien species (as influenced by
environmental factors) and to assist in quantifying the impact of invasive species
at broad scales based on responses on a finer scale (Odindi et al. 2016; Mavimbela
et al. 2018).
11.4.1 Conflicts of Interest
Invasive species that provide both ES and EDS often generate conflicts around their
use and management. Aesthetic and recreational opportunities provided by invasive
alien tree species are highly valued in urban areas through their provision of shade,
and plantings for green spaces, street plantings or gardens around urban centres
(Dickie et al. 2014). For example, attempts to regulate and remove planted individuals of Jacaranda mimosifolia in Pretoria (planted in gardens and along streets for
aesthetic purposes) to eliminate seed sources driving invasion of savanna areas,
resulted in massive public resistance (Dickie et al. 2014).
Conflicts of interest are most obvious in urban areas with a steep urban-rural
gradient, as epitomised by Cape Town (Alston and Richardson 2006; Dickie et al.
2014). For example, Eucalyptus and Pinus species, historically grown in plantations
along the urban edge of Cape Town, are utilised for recreation by the city’s residents,
many of whom regard the trees as attractive and ecologically beneficial (van Wilgen
and Richardson 2012). As a result, control programs have been controversial.
Managing invasive animals is often controversial and residents frequently challenge the ethics of killing or removing animals, highlighting the perceived cruelty of
these operations. For example, a decision to control Mallards (Anas platyrhynchos)
due to their impacts on native waterfowl was met with substantial public resistance
(Gaertner et al. 2016). Management efforts were effectively halted because the
arguments for the campaign (genetic contamination of a single native species)
were less convincing to the public than arguments for the widespread ecological
impacts of more damaging invasive species (Gaertner et al. 2017a).
There is increasing recognition of the importance of engaging stakeholders
affected by alien species or by their management (Novoa et al. 2018). Consideration
of stakeholder views and the social consequences of management actions are needed
to supplement traditional management approaches (Gaertner et al. 2016). Novoa
et al. (2018) developed a step-by-step approach to engaging stakeholders in the
management of alien species, and Gaertner et al. (2017a) developed a framework
which groups species into three management approaches (control priority, active
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L. J. Potgieter et al.
EDS (Potgieter et al. 2017; Vaz et al. 2017). Decisions must be made on whether to
manage to enhance ES provision, or to minimise EDS. Such decisions are largely
context-specific, and managers need to consider the knock-on effects when reducing
EDS or enhancing specific ES, as other ES may be indirectly disrupted, or novel
EDS created. Decisions need to be transparent and must consider opinions of a wide
range of stakeholders including the public and those involved in urban land-use and
ecosystem management decisions (Novoa et al. 2018). Furthermore, a variety of
approaches (e.g. citizen science, remote sensing, and active surveillance) are needed
to determine the distribution patterns of native and alien species (as influenced by
environmental factors) and to assist in quantifying the impact of invasive species
at broad scales based on responses on a finer scale (Odindi et al. 2016; Mavimbela
et al. 2018).
11.4.1 Conflicts of Interest
Invasive species that provide both ES and EDS often generate conflicts around their
use and management. Aesthetic and recreational opportunities provided by invasive
alien tree species are highly valued in urban areas through their provision of shade,
and plantings for green spaces, street plantings or gardens around urban centres
(Dickie et al. 2014). For example, attempts to regulate and remove planted individuals of Jacaranda mimosifolia in Pretoria (planted in gardens and along streets for
aesthetic purposes) to eliminate seed sources driving invasion of savanna areas,
resulted in massive public resistance (Dickie et al. 2014).
Conflicts of interest are most obvious in urban areas with a steep urban-rural
gradient, as epitomised by Cape Town (Alston and Richardson 2006; Dickie et al.
2014). For example, Eucalyptus and Pinus species, historically grown in plantations
along the urban edge of Cape Town, are utilised for recreation by the city’s residents,
many of whom regard the trees as attractive and ecologically beneficial (van Wilgen
and Richardson 2012). As a result, control programs have been controversial.
Managing invasive animals is often controversial and residents frequently challenge the ethics of killing or removing animals, highlighting the perceived cruelty of
these operations. For example, a decision to control Mallards (Anas platyrhynchos)
due to their impacts on native waterfowl was met with substantial public resistance
(Gaertner et al. 2016). Management efforts were effectively halted because the
arguments for the campaign (genetic contamination of a single native species)
were less convincing to the public than arguments for the widespread ecological
impacts of more damaging invasive species (Gaertner et al. 2017a).
There is increasing recognition of the importance of engaging stakeholders
affected by alien species or by their management (Novoa et al. 2018). Consideration
of stakeholder views and the social consequences of management actions are needed
to supplement traditional management approaches (Gaertner et al. 2016). Novoa
et al. (2018) developed a step-by-step approach to engaging stakeholders in the
management of alien species, and Gaertner et al. (2017a) developed a framework
which groups species into three management approaches (control priority, active
298
L. J. Potgieter et al.