Terrestrial Vertebrate Invasions in South Africa

Abstract

In this chapter we review the current knowledge on terrestrial vertebrate invasions in South Africa. Thirty species of mammals, birds, reptiles and amphibians are considered to have arrived over the last 10,000 years, with two thirds having become invasive in the last 150 years. Half of the species are mammals, a third birds, with three reptiles and two amphibians. Although there are multiple pathways, there appears to be a trend from species that were deliberately introduced in the past, to accidental introductions in the last~100 years, which are a by-product of increasing trade, both internationally and within South Africa. Few invasive terrestrial vertebrate species have had their impacts formally assessed within South Africa, but international assessments suggest that many can have Moderate or Major environmental and socioeconomic impacts. Of particular concern is the growing demand for alien pets within the region, with increasing amounts of escapees being encountered in the wild. We consider the importance that the NEM: BA Alien and Invasive Species Regulations have had on the research of invasive terrestrial vertebrates in South Africa, and emphasise the importance of regulations for domestic exotics.

Biological Invasions in South Africa: An Overview

“…For example, Picker and Griffiths (2017) documented that South Africa had 41 naturalised alien vertebrate species that had their origins outside the geopolitical borders of the country. Van Wilgen and included all alien vertebrate species, and so had a much higher number (283), although they also provided a number of naturalised species as 45; and in this book, Measey et al (2020a) lists 30 terrestrial vertebrate species in Chap. 5, and Weyl et al 2020 lists 21 fish species in Chap.…”

“…3-11) deals with the current situation. The first chapters focus on specific taxa-terrestrial plants (Richardson et al 2020b), aquatic plants (Hill et al 2020a), terrestrial vertebrates (Measey et al 2020a), terrestrial invertebrates (Janion-Scheepers and Griffiths 2020), and pathogens that affect mammals, including humans (van Helden et al 2020). The ecology of diseases, such as those covered by van Helden et al (2020), has not yet been integrated within the invasion science agenda in South Africa.…”

Assessing the potential impacts of non-native small mammals in the South African pet trade

“…material 2, Table S2. An asterisk indicates species established in South Africa (see Picker andGriffiths 2017, andMeasey et al 2020). (Table 1).…”

“…The latter has gained considerable attention over the past decades as the global trade in live animals increases (Keller and Lodge 2007;Faulkner et al 2016;Ng et al 2016;Lockwood et al 2019). Some of the nonnative pet species may establish self-sustaining populations through accidental escapes and intentional releases (Gaertner et al 2015;da Rosa et al 2017); for example, European rabbit Oryctolagus cuniculus, eastern grey squirrel Sciurus carolinensis, common marmoset Callithrix jacchus and the black tufted-ear marmoset Callithrix penicillata (Huynh et al 2010;da Rosa et al 2017;Measey et al 2020).…”

The implications of the reclassification of South African wildlife species as farm animals

“…For instance, rabbits can cause massive environmental impacts. 13 Due to the lack of transparency and details, we do not know how these species will be managed and, therefore, what the ecological implications will be. A logical endpoint of this legislation is that we will have two populations of each species: one wild and one domesticated.…”