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Hawai'i Forestry Extension

Economics of Managing Invasive Species in Tropical and Subtropical Areas of the US-Hawai‘i

Carol A Ferguson, Department of Natural Resources and Environmental Management, UH-CTAHR

The specific problem addressed by this project is the absence of a comprehensive pest risk management system that combines economics and scientific analyses into a single decision-making framework. Although the problem of invasives has as much to do with economics as with ecology, the decision-making framework on introduction and spread of pests has traditionally been the domain of the biological scientific community. However, as present management systems have become overwhelmed by the increase in introductions, the scientific community is now calling for input by economics and other social science disciplines to answer questions and identify strategic actions to address the problems. This project will develop and test a comprehensive modeling framework and risk management computer software to manage invasive species, plus establish a collaborative interdisciplinary network for invasive species management.

Economics of Managing Invasive Species Project Website

Dr. Carol Ferguson (cafergus@hawaii.edu)
Phone: 808-956-8864
Fax: 808-956-6539

FUNDING has been provided to CTAHR for this research from the USDA Cooperative State Research, Education, and Extension Service Project HAW00107-05G.


1) Develop a comprehensive risk management system for invasive species that incorporates biological science with probabilities and economic impacts into a single decision-making framework.
2) Develop a collaborative interdisciplinary network of institutions and persons involved with invasive species management.


Conceptual framework/modeling system: The first phase of the project developed a preliminary framework that incorporates the biological characteristics of an introduced species, including the probability of occurrence and economic impacts, differences in regions. The framework is providing methodological guidance for applications to regional case studies.

Case studies: Four invasive species have been selected by Hawaii to test and demonstrate the modeling framework. These include strawberry guava, miconia, apple snails, and (with Guam) brown tree snakes. Each case study will estimate the economic effects from species introduction and outcomes of likely management scenarios.

Pest risk management software: The project will develop computer software that will integrate the information requested for pest risk assessment into a standardized tool that can be used by operational managers. The software will use the above conceptual framework and be tested with data from the case studies. Software programming will use Business Unified Modeling Language (BUML) with user-specified long-term goal and process controls (pest control resources and impacts). The case studies will demonstrate different analytical approaches in using the software. Interdisciplinary network: the project will continue sponsoring inter- and intra-regional workshops to discuss invasive species research and management. The pest risk management software will be demonstrated to prospective users in the Pacific in a satellite transmission. Other activities are extending project outputs on university websites and publication of final results.


2005/09 TO 2006/09

In-depth interviews of taro farmers in Hawaii indicate significant damages from apple snails, specifically Pomecea canaliculata. Farm-level damages (control costs and corm yield loss) averaged $5,028/ac/year. A simulation model for a prototype two-island system found that an interisland quarantine could have reduced snail damages by almost $2 million over a 50-year period (net present value at 5% discount rate). Costs for controlling strawberry guava (Psidium cattleianum) were estimated for two sites in Hawaii. Herbicide treatments at Kokee (Kauai) were relatively inexpensive ($520/ac over 105 ac) but provided only good short-term control (89% foliar reduction vs. 38% for stem count). In an Army experiment at Schofield Barracks (Oahu), costs of mechanical removal combined with herbicide were much higher at ~$9,000-44,000/ac due to small scale (130sq.m plots), airlifting equipment to the remote mountain site, indifference to expenses. A case study on white spot syndrome virus compared 2004 outbreaks at a shrimp farm in Guam (SCOAP) and one in Kauai, Hawaii (Ceatech). Production losses were estimated (annual basis) at $405,000 for the Guam farm (11 ponds) and $2 million for the Hawaii farm (hatchery with 40 growout ponds). Both producers lacked financial resources to recover from the outbreak and closed their businesses. Hawaii residents were surveyed (N=356) about controlling Miconia calvescens, a highly invasive plant species. The survey found that loss of biodiversity and soil erosion impacts were more important than miconia control costs, and that residents (taxpayers) were willing to pay an average $12-14 per year to prevent the loss of 50 native species. Annual economic losses from the establishment of the brown tree snake (Boiga irregularis) in Hawaii were estimated at ~$350,000 for medical costs, and $335-454 million in power outages (damaged equipment and lost productivity). Ongoing interviews of wildlife managers and researchers indicate that the loss of native birds in Hawaii from BTS would be more extensive and costly than in Guam. In two hypothetical scenarios, Baseline protection would be needed for 10 bird species, while an additional 11 species would be covered in an Expanded scenario.


2005/09 TO 2006/09

In the National Invasive Species Council's most recent (FY06) plan, brown tree snake has been retained as one of six targeted species with a 12% increase in budget over the previous year. In Hawaii, the state legislature has renewed a $4 million special program for invasive species management. The problem of apple snails was featured in the spring 2006 newsletter of the Kauai Invasive Species Committee. The latest (April-June 2006) activity report by the Maui Invasive Species Committee showed that more than half of field crew time was spent in miconia control.

PUBLICATIONS (not previously reported): 2005/09 TO 2006/09

1. Levin, P. et al., 2006 (in press), Apple snail invasions and the slow road to control: ecological, economic, agricultural and cultural perspectives in Hawaii, in R.C. Joshi (ed.), Global Advances in Ecology and Management of Golden Apple Snails, Philippine Rice Research Institute.

2. Chan-Halbrendt et al., 2006, Willingness to pay for Miconia management program, paper presented at 2006 Hawaii Conservation Conference, Honolulu, July 26-28.

Last Updated On 5/23/2007
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