Box 17.1 (continued)
EICAT is in the process of being adopted by the IUCN as a standard system
for classifying invasive alien species based on the nature and magnitude of
their impacts (see https://www.iucn.org/theme/species/our-work/invasive-spe
cies/eicat for more details).
17.2.1 Impact-Scoring Schemes
The Environmental Impact Classification for Alien Taxa has been applied to various
taxa that are known to occur as alien species in South Africa including grasses
(Visser et al. 2017; Nkuna et al. 2018; Canavan et al. 2019), amphibians (Kumschick
et al. 2017), birds (Evans et al. 2016), mammals (Hagen and Kumschick 2018), fish
(Marr et al. 2017), gastropods (Kesner and Kumschick 2018), and some other
invertebrates (Nelufule 2018). Most EICAT assessments performed to date have
been done at a global scale, i.e. including all records of impact of a given species in
its global alien range. It is important to note that although global assessments are
comprehensive, there will need to be regularly updated as further assessments are
done at national scales. In South Africa, national-level EICAT assessments have
been done for some alien grasses (Visser et al. 2017) and fishes (Marr et al. 2017)
(Table 17.1).
A global effort is in progress to use EICAT to assess all species in their alien
ranges, and researchers from South Africa have contributed many assessments to
date. Evidence-based assessments are also needed in South Africa for regular
reporting on the status of biological invasions (van Wilgen and Wilson 2018; Wilson
et al. 2018; van Wilgen et al. 2020a, Chap. 1). Moreover, the risk analysis framework currently used as evidence to support listing of alien species in South Africa
(Kumschick et al. 2018) requires impact assessments analogous to EICAT
(Kumschick et al. 2020, Chap. 20). However, while some progress has been made,
there is still a very large number of species that have to be formally assessed in
South Africa.
17.2.1.1 Grasses
There are six grass species that have had EICAT assessments done at a national scale
for South Africa, with Arundo donax (Giant Reed) and Glyceria maxima (Reed
Meadow Grass) evaluated as having major impacts (Visser et al. 2017; Nkuna et al.
2018; VK Nkuna, unpublished data). These two species have been implicated in
competitively displacing native species; A. donax, for example, dominates riparian
areas and can locally exclude native plants (Holmes et al. 2005; Guthrie 2007), while
G. maxima has locally displaced some native wetland species (Mugwedi 2012).
17 An Evaluation of the Impacts of Alien Species on Biodiversity
493
EICAT is in the process of being adopted by the IUCN as a standard system
for classifying invasive alien species based on the nature and magnitude of
their impacts (see https://www.iucn.org/theme/species/our-work/invasive-spe
cies/eicat for more details).
17.2.1 Impact-Scoring Schemes
The Environmental Impact Classification for Alien Taxa has been applied to various
taxa that are known to occur as alien species in South Africa including grasses
(Visser et al. 2017; Nkuna et al. 2018; Canavan et al. 2019), amphibians (Kumschick
et al. 2017), birds (Evans et al. 2016), mammals (Hagen and Kumschick 2018), fish
(Marr et al. 2017), gastropods (Kesner and Kumschick 2018), and some other
invertebrates (Nelufule 2018). Most EICAT assessments performed to date have
been done at a global scale, i.e. including all records of impact of a given species in
its global alien range. It is important to note that although global assessments are
comprehensive, there will need to be regularly updated as further assessments are
done at national scales. In South Africa, national-level EICAT assessments have
been done for some alien grasses (Visser et al. 2017) and fishes (Marr et al. 2017)
(Table 17.1).
A global effort is in progress to use EICAT to assess all species in their alien
ranges, and researchers from South Africa have contributed many assessments to
date. Evidence-based assessments are also needed in South Africa for regular
reporting on the status of biological invasions (van Wilgen and Wilson 2018; Wilson
et al. 2018; van Wilgen et al. 2020a, Chap. 1). Moreover, the risk analysis framework currently used as evidence to support listing of alien species in South Africa
(Kumschick et al. 2018) requires impact assessments analogous to EICAT
(Kumschick et al. 2020, Chap. 20). However, while some progress has been made,
there is still a very large number of species that have to be formally assessed in
South Africa.
17.2.1.1 Grasses
There are six grass species that have had EICAT assessments done at a national scale
for South Africa, with Arundo donax (Giant Reed) and Glyceria maxima (Reed
Meadow Grass) evaluated as having major impacts (Visser et al. 2017; Nkuna et al.
2018; VK Nkuna, unpublished data). These two species have been implicated in
competitively displacing native species; A. donax, for example, dominates riparian
areas and can locally exclude native plants (Holmes et al. 2005; Guthrie 2007), while
G. maxima has locally displaced some native wetland species (Mugwedi 2012).
17 An Evaluation of the Impacts of Alien Species on Biodiversity
493