Research Themes: (D) Managing introduced species and genotypes and post-removal strategies: development of effective and environmentally sound responses

While the previous three research foci concern strategies to prevent invasions, the fourth emphasizes responses to invasions that have already occurred. Research to improve management of invasives is germane both to species that have invaded new environments and to GEOs that have escaped the habitats into which they were released.

Management options for invasive species and genotypes range from eradication and suppression to post-removal recovery and adaptive management designs. Some control strategies have been used to selectively eradicate insect and plant species, but selective eradication is rare for vertebrates. In many instances, the need for new approaches is pressing, both because nonselective toxicants are often the only available option and more generally, because new approaches could reinforce integrated pest management (IPM) strategies. Moreover, in some systems, complications arise because removal of introduced species can have adverse consequences. Successful management of invasives can also hinge upon cooperation of the public. For instance, in areas where boaters are more willing to clean boats between lakes, invasive aquatics such as Eurasian water milfoil spread more slowly than in other areas. Further, local eradication of the invasive Asian longhorned beetle was achieved in Chicago but not New York, which differed in a combination of factors including local policy, funding, and behavior of the public. Such cases highlight the fact that a comprehensive approach to managing invasives incorporates human behavior as a factor in understanding management efficacy.

Research of our IGERT faculty addresses four general issues of management: (1) new techniques for controlling and removing invasive species (Sorensen, Newman, Kapuscinski, Heimpel), as well as their ecological risks and feasibility, including the impact of human behavior and choice on control potential, (2) selective control methods (e.g., pheromones and exotic natural enemies) to minimize risk to non-target organisms, as well as inadvertent impacts of invasive species removal on non-target organisms (e.g., mortality from control agents or transfer of poisons through food chains), (3) the transition from removal to recovery, and (4) adaptive management systems for invasives. Managing the risks of control measures is an essential component of ERA, and IGERT faculty study selective control from the perspective of both controlling invasives and minimizing non-target risks.

Table 1. Current research of IGERT faculty on invasive species management. Management techniques include biological control, genetic modifications and pheremone release.

Many of our research activities concerning risk management will employ an adaptive management framework. Adaptive management involves repeated cycles of program design, implementation, and evaluation, in a deliberate ‘learn-as-you-go’ approach. IGERT faculty currently employ this mode of applied research. Andow and Ives (2002) have outlined an adaptive system for managing the evolution of resistance to GE Bt crops, but these ideas have not yet been implemented. In another context, Jordan et al. (2005) have facilitated ‘learning groups’ for adaptive implementation of invasive management techniques in agroecosystems. Adaptive management has also been advocated for biological control, but has been implemented only rarely. Our IGERT faculty and students will synergistically develop adaptive management systems for diverse situations and determine the feasibility of their implementation. Dynamic management will serve as a common framework for addressing important management questions, including: Which species or genotypes of biological control agents provide the best control? What are the implications of differing spread rates and patterns for optimal management of invasive species or genotypes? How can evolution of resistance to a novel control measure be slowed? How will human behavior and preference influence the effectiveness of the control measures and be incorporated into management adaptation? Thus, IGERT students could participate in developing best management practices that maximize efficacy while minimizing risk to non-target organisms. Table 1 lists systems available for this kind of research within our IGERT.

Problems of system recovery after removal or suppression of invasives are also of mutual concern. Several of our IGERT faculty (Galatowitsch, Hobbie, Jordan, Larson, Newman) work on post-removal restoration of ecosystems in which invasives have disrupted food-webs or altered soil microbial and nutrient dynamics. We will predict when post-removal restoration is likely to be necessary and determine the underlying mechanisms for different responses to removal. Major issues of common interest include roles of anthropogenic disturbance and forcing factors such as eutrophication, dispersal limitation, propagule depletion, and biotic-abiotic feedbacks that may operate in community assembly after removal, as well as feedbacks between human behavior and environment. We will develop modeling approaches for identifying appropriate removal strategies and post-removal management. In particular, we will address how the rate of removal affects restoration outcomes and how landscape context affects restoration success.

In this Section

A) Evaluating effectiveness of regulation using retrospective analysis

B) Improving theory and models for ecological risk assessment

C) Addressing uncertainty in risk assessments

D) Managing introduced species and genotypes and post-removal strategies