EFFECT OF ECOSYSTEM SIZE AND POPULATION PRODUCTIVITY ON FEASIBILITY OF GENETIC BIOCONTROL FOR INVASIVE SPECIES

Population resistance and resilience to disturbance are typically considered beneficial attributes, yet present substantial challenges to invasive species control efforts. The use of Trojan Y Chromosomes (TYC) is increasingly being considered for invasive species control, but has largely been limited to small ecosystems with small-bodied and short-lived species. Controlling large-bodied and long-lived species in large ecosystems presents a greater challenge. Here, we use a simulation modeling approach to characterize the effectiveness of TYC stocking for biocontrol across a range of ecosystem sizes and population productivities, representing a range of population resistance and resilience conditions. Our results indicate that more productive populations are able to persist longer than less productive populations under the same YY stocking intensity, and that this relationship intensifies with increasing ecosystem size. We identify threshold levels of stocking intensity below which control efforts are ineffective, and find that stocking YY- females is generally more effective than stocking YY-males. Finally, coupling TYC stocking with concurrent mechanical removal efforts increases control program efficacy. Given increasing interest in using TYC to control invasive species, it is imperative to recognize the ecological conditions under which TYC strategies are likely to be effective. The thresholds identified herein can help managers determine whether TYC stocking represents a feasible approach given their specific system, population productivity, and available resources.

Primary Presenter: Ellie Wallace, Utah State University (ellie.wallace@usu.edu)

Authors:

Ellie Wallace, Utah State University  (ellie.wallace@usu.edu)

Kevin Landom, Utah State University  (kevin.landom@usu.edu)

Timothy E. Walsworth, Utah State University  (timothy.walsworth@usu.edu)