WHERE TO AIM: EVALUATING MICONIA MANAGEMENT WITH HERBICIDE BALLISTIC TECHNOLOGY IN MAUI

Abstract

Introduced on Maui in the early 1970’s, Miconia calvescens spread unabated until formally recognized as an invasive species in 1991. In 2012, herbicide ballistic technology (HBT) became the primary treatment method for the inaccessible terrain of east Maui. Eradication efforts have been unsuccessful, and the Maui Invasive Species Council has declared Miconia calvescens as economically beyond eradication. With limited funding and invasion potential increasing, ad hoc prevention strategies are no longer viable and alternative management approaches are needed for miconia. My thesis research developed a bioeconomic model to forecast miconia invasion outcomes under different management scenarios countering the dispersal of incipient populations with explicit spatial and temporal components across decadal timescales. Biological and economic outcomes are evaluated after the culminating time step. In chapter 2, a first iteration was coded on a set of defined management actions: (i) inaction, (ii) containment, and (iii) asset protection, where protection under management and damage without management were calculated as benefit-cost ratios. The model forecasted incipient invasions accruing $295k in present value damages over 20 years without management. Additionally, the benefits of management and the preference between offensive containment and defensive protection were influenced by the value and proximity of the conservation assets. Here, containment strategies were preferred when interventions were spatially closer to the maternal source and with greater distance from assets are further away. In Chapter 3, I tested a second model, management actions were assessed based on return on investment per $1000 of future plants prevented. The results indicated that containing the invasion closer to the maternal source was the most cost-effective approach with the highest return on investment. Overall, in both scenarios the model also demonstrated that aggressive management actions are the most cost-effective approach, with benefit cost ratios and returns on investment better than more permissive approaches in all scenarios.