mammals, 30% invertebrates, 12% reptiles, 9% amphibians and 7% birds: alien prey
items were less than 10% of the total (F Morling unpublished data). Individuals have
a home range of around 30 ha, with animals moving up to 0.85 km in a straight line
(George 2010).
In addition to predation, cats may have a substantial sub-lethal or indirect effect
on avifauna, or facilitate invasion meltdown from third-party predators, such as
corvids (Bonnington et al. 2013). High densities of these predators around the
nesting sites of birds are thought to reduce provisioning to nestlings and result in
reduced fitness. Cats continue to be stocked in many areas as they are perceived as
effectively controlling invasive rodent populations (see below). For example, cats
(together with domestic dogs, Canis lupus familiaris) create a landscape of fear in
rural southern African homesteads, changing the foraging patterns of house rats and
other pest rodents (Themb’alilahlwa et al. 2017). Other impacts in South Africa
include the potential for hybridisation with African wildcats, Felis silvestris lybica.
In a genetic study, le Roux et al. (2015) found evidence of hybridisation linked with
a human population pressure gradient, with pure wildcats in the Kgalagadi
Transfrontier Park, while samples from around Kruger National Park demonstrated
some introgression. Despite their clear MR impacts (Hagen and Kumschick 2018),
control of cats has the potential to cause conflicts thought to include aesthetic and
moral values (Zengeya et al. 2017), hence they are only recognised in the Regulations in specific contexts (on South Africa’s offshore islands: see Chap. 8, Greve
et al. 2020).
5.3.3 Equus asinus (Donkeys)
Donkeys derive from native African wild asses, Equus africanus, which are still
extant in Eritrea and Ethiopia (Moehlman et al. 2015). They, however, arrived in
South Africa via shipping with Europeans in the 1600s (Blench 2004). Little is
known about the extent and impact of feral donkeys in South Africa, although it was
suggested the greatest threat they pose in this region is hybridising with Cape
Mountain Zebra, Equus zebra zebra (Brooke et al. 1986; Fig. 5.1), producing a
‘zonkey’. They are used by various communities and farmers as working animals,
but are often neglected and allowed to roam free, causing competition between
donkeys and other livestock, such as goats and sheep (Cupido and Samuels 2009;
Samuels et al. 2016). A large feral donkey problem was reported from Paulshoek in
the Karoo, where residents complained that donkeys were destructive towards
vegetation (Hoffman et al. 1999). Recent aerial counts around Steinkopf and
Leliefontein estimate that there are as many as 274 donkeys in this area, potentially
consuming ~8% of the grazing available for productive livestock (Muller and
Bourne 2018). Although there are no data to show the effect of donkeys on the
environment in South Africa, they lead to local degradation of the environment, as
occurs in Australia. In Australia, there are an estimated 5 million feral donkeys
(Roots 2007) which are regarded as an invasive pest and have negative impacts on
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J. Measey et al.
items were less than 10% of the total (F Morling unpublished data). Individuals have
a home range of around 30 ha, with animals moving up to 0.85 km in a straight line
(George 2010).
In addition to predation, cats may have a substantial sub-lethal or indirect effect
on avifauna, or facilitate invasion meltdown from third-party predators, such as
corvids (Bonnington et al. 2013). High densities of these predators around the
nesting sites of birds are thought to reduce provisioning to nestlings and result in
reduced fitness. Cats continue to be stocked in many areas as they are perceived as
effectively controlling invasive rodent populations (see below). For example, cats
(together with domestic dogs, Canis lupus familiaris) create a landscape of fear in
rural southern African homesteads, changing the foraging patterns of house rats and
other pest rodents (Themb’alilahlwa et al. 2017). Other impacts in South Africa
include the potential for hybridisation with African wildcats, Felis silvestris lybica.
In a genetic study, le Roux et al. (2015) found evidence of hybridisation linked with
a human population pressure gradient, with pure wildcats in the Kgalagadi
Transfrontier Park, while samples from around Kruger National Park demonstrated
some introgression. Despite their clear MR impacts (Hagen and Kumschick 2018),
control of cats has the potential to cause conflicts thought to include aesthetic and
moral values (Zengeya et al. 2017), hence they are only recognised in the Regulations in specific contexts (on South Africa’s offshore islands: see Chap. 8, Greve
et al. 2020).
5.3.3 Equus asinus (Donkeys)
Donkeys derive from native African wild asses, Equus africanus, which are still
extant in Eritrea and Ethiopia (Moehlman et al. 2015). They, however, arrived in
South Africa via shipping with Europeans in the 1600s (Blench 2004). Little is
known about the extent and impact of feral donkeys in South Africa, although it was
suggested the greatest threat they pose in this region is hybridising with Cape
Mountain Zebra, Equus zebra zebra (Brooke et al. 1986; Fig. 5.1), producing a
‘zonkey’. They are used by various communities and farmers as working animals,
but are often neglected and allowed to roam free, causing competition between
donkeys and other livestock, such as goats and sheep (Cupido and Samuels 2009;
Samuels et al. 2016). A large feral donkey problem was reported from Paulshoek in
the Karoo, where residents complained that donkeys were destructive towards
vegetation (Hoffman et al. 1999). Recent aerial counts around Steinkopf and
Leliefontein estimate that there are as many as 274 donkeys in this area, potentially
consuming ~8% of the grazing available for productive livestock (Muller and
Bourne 2018). Although there are no data to show the effect of donkeys on the
environment in South Africa, they lead to local degradation of the environment, as
occurs in Australia. In Australia, there are an estimated 5 million feral donkeys
(Roots 2007) which are regarded as an invasive pest and have negative impacts on
122
J. Measey et al.