Modeling the eradication of invasive mammals using the sterile male technique

Abstract

Large vertebrates, like the domestic goat (Capra hircus), have been transported all over the world and are an ecological disaster to numerous island and mainland ecosystems. Eradication measures for such species are generally centered on lethal methods of removing individuals, an increasingly difficult process as populations become smaller and individual animals become much more difficult to detect. In addition, methods of lethal removal are becoming less desirable in the public eye, prompting the necessity to explore alternatives. Here we investigate the use of the sterile males technique as an effective strategy in the eradication of large mammals. The results of our simulations suggest that the use of sterile males as a single strategy would only be an effective measure to eradicate relatively small (no more than 100 individuals) isolated feral vertebrate populations. However, our results indicate that the technique could be employed as a successful and potentially cost-effective end-point complement to lethal control and/or as a preventative measure against re-invasion.

Feral rabbit populations in a peri-urban area: insights about invasion dynamics and potential management strategies

“…Communication campaigns were found to be effective at increasing human acceptance of invasive alien species management, at least when people are interested about biological invasions (Sol Hart and Larson 2014), and we believe that this might be the case for our study area. To date, control of invasive mammal species throughout sterilization has been achieved only on islands or at urban parks (Da Silva et al 2010;Scapin et al 2019), and our case study might contribute to broaden evidence about the effectiveness of nonlethal management of invasive alien species.…”

Modelling the population control of the domestic cat: an example from an island in Brazil

“…Gonçalves da Silva et al (2009) carried out a modelling study on the effects of castration on large exotic mammals on islands. Using a model (Leslie's matrix type II) to simulate population decrease, they evaluated three eradication scenarios: hunting, castration, and both.…”

Towards the genetic control of invasive species

“…hunting, fishing or trapping) (Thresher 2007) and classical biocontrol (Thresher et al 2014). The combination of sterile male goat releases (analogous to a bisex-lethal system) and targeted hunting is predicted to decrease the hunting pressure (by c. 40%) and release ratio (by c. 93%) required to control invasive goat populations compared to either method used separately (da Silva et al 2010). …”

“…Similarly, barrier zones could be used to prevent invasion in the first instance, by releasing GPM individuals into high-risk transport areas such as airports or docks without the risk of these individuals establishing (Thresher et al 2014; Lee et al 2013). Models representing island goat invasions suggest that the presence of as few as 20 sterile (bisex-lethal) males could provide such an effective “sentry system” against future invasion (da Silva et al 2010). …”