Alien Species Risk Assessment

Only after detecting an invasive alien species is it possible to intervene, and prevent, manage or stop the invasion. The control measures needed are based on the extent of the invasion, the species invading and in which environment it is invading.

There is a large gap in knowledge and data regarding invasive reptiles (Moffitt et al. 2008), which threatens successful control and eradication (Hoskin 2011). Many of the eradication and control measures utilized in the past are either not shared (Howald et al. 2007), shared in grey literature or only focus on successful programs (Myers 2003, Simberloff 2003;2009). Very little research has focused on the initial dispersal and spread of invasions, adding to the unreliability of risk assessments

There are many forms and methods of risk assessment, and a comprehensive overview of these is given by Hayes and Barry (2008). No one method can be utilized for all species with great accuracy, there is however consensus within literature on risk assessments as to which four factors influence the likelihood of successful invasion the most (Bomford et al. 2005, Hayes and Barry 2008, Bomford et al. 2009, Kraus 2009, Mahoney et al.

2008). However, as the popularity of exotic pets, and subsequent abundance of non-native reptiles in the country grows, the probability of alien reptiles establishing themselves in South Africa increases(Van Wilgen and Richardson 2012). The examples from other countries show the potential threats and should act as a warning. Furthermore, impacts of invasive alien herpetofauna have not been studied to the same extent as other invasions. Partly through lack of focus, but also due to the fact that herpetofauna are hard to study in their natural environments, and that changes brought by these aliens can be too subtle to detect (Kraus 2009).

Following a risk assessment, action can be undertaken to prevent or stop an invasion. If a species has established, the alternatives are to eradicate or accept and control the invasive species. Prevention is by far the most preferable as it is the most cost-effective (Jarrad et al. 2011b), least detrimental to native flora and fauna and most likely to succeed (Genovesi 2005;2007, Bogich et al. 2008, Bomford et al. 2009). The best way to prevent invasion is to keep unwanted aliens outside the country. This requires legislation, sufficient resources and knowledge and data on pathways and the process of