store them in nests below the soil. The seeds were left on the soil surface, where they
were eaten by vertebrate and invertebrate seed predators. Bond and Slingsby (1983)
estimated that L. humile displacement of native ants could threaten the long-term
survival of approximately 1000 fynbos plant species that were dependent on native
ants for the dispersal and protection of their seeds.
Among the marine invertebrates, Mytilus galloprovincialis (Mediterranean Mussel) has had significant impacts in South African marine environments (Robinson
et al. 2020, Chap. 9). First recorded in South Africa in the late 1970s, it presently
occurs along the whole of the west coast and as far east as East London (approx.
2000 km of coastline) (Robinson et al. 2005). Within its invaded range, it has been
implicated in causing impacts on native species and altering the structure of rocky
shore communities. Along the west coast, M. galloprovincialis competively
excludes native species such as mussels and limpets from prime habitas (Robinson
et al. 2007), while along the south coast it co-exists with the native Perna perna
(Brown Mussel) (Bownes and McQuaid 2006). Interestingly, M. galloprovincialis
forms complex mussel beds that have increased habitat availability leading to an
increase in the diversity and abundance of native fauna on invaded shores
(Sadchatheeswaran et al. 2015).
17.2.2.3 Mammals
Of the 42 alien mammal species that have been recorded in South Africa, 8 species
have been assessed using expert opinion as causing major impacts in South Africa
(van Wilgen and Wilson 2018). Six of these (R. rattus, R. norvegicus, F. catus, M.
musculus, S. scrofa and C. hircus) cause massive impacts in the country, in similar
ways to those identifed by formal global EICAT assessments (see Sect. 17.2.1.6).
For the remainder, Hippotragus equinus koba (Western Roan) has been implicated
in hybridising with local sub-species (Mathee and Robinson 1999; Alpers et al.
2004; van Wyk et al. 2019) and the impacts of Macaca fascicularis (Crab-Eating
Macaque) are not well documented in South Africa, so their potential impacts can
only be inferred from their global invasive range.
17.2.2.4 Fishes
Five fish species were classified by experts as causing major to severe impacts in
invaded catchments in South Africa (Zengeya et al. 2017). Micropterus dolomieu,
M. salmoides, O. mykiss and S. trutta had major impacts through mainly competition
and predation. Oreochromis niloticus was assessed as having severe impacts mainly
through hybridisation with congeneric native species.
502
T. A. Zengeya et al.
were eaten by vertebrate and invertebrate seed predators. Bond and Slingsby (1983)
estimated that L. humile displacement of native ants could threaten the long-term
survival of approximately 1000 fynbos plant species that were dependent on native
ants for the dispersal and protection of their seeds.
Among the marine invertebrates, Mytilus galloprovincialis (Mediterranean Mussel) has had significant impacts in South African marine environments (Robinson
et al. 2020, Chap. 9). First recorded in South Africa in the late 1970s, it presently
occurs along the whole of the west coast and as far east as East London (approx.
2000 km of coastline) (Robinson et al. 2005). Within its invaded range, it has been
implicated in causing impacts on native species and altering the structure of rocky
shore communities. Along the west coast, M. galloprovincialis competively
excludes native species such as mussels and limpets from prime habitas (Robinson
et al. 2007), while along the south coast it co-exists with the native Perna perna
(Brown Mussel) (Bownes and McQuaid 2006). Interestingly, M. galloprovincialis
forms complex mussel beds that have increased habitat availability leading to an
increase in the diversity and abundance of native fauna on invaded shores
(Sadchatheeswaran et al. 2015).
17.2.2.3 Mammals
Of the 42 alien mammal species that have been recorded in South Africa, 8 species
have been assessed using expert opinion as causing major impacts in South Africa
(van Wilgen and Wilson 2018). Six of these (R. rattus, R. norvegicus, F. catus, M.
musculus, S. scrofa and C. hircus) cause massive impacts in the country, in similar
ways to those identifed by formal global EICAT assessments (see Sect. 17.2.1.6).
For the remainder, Hippotragus equinus koba (Western Roan) has been implicated
in hybridising with local sub-species (Mathee and Robinson 1999; Alpers et al.
2004; van Wyk et al. 2019) and the impacts of Macaca fascicularis (Crab-Eating
Macaque) are not well documented in South Africa, so their potential impacts can
only be inferred from their global invasive range.
17.2.2.4 Fishes
Five fish species were classified by experts as causing major to severe impacts in
invaded catchments in South Africa (Zengeya et al. 2017). Micropterus dolomieu,
M. salmoides, O. mykiss and S. trutta had major impacts through mainly competition
and predation. Oreochromis niloticus was assessed as having severe impacts mainly
through hybridisation with congeneric native species.
502
T. A. Zengeya et al.