Robert G. Haight

Economic Impacts of Non-Native Forest Insects in the Continental United States

Reliable estimates of the impacts and costs of biological invasions are critical to developing credible management, trade and regulatory policies. Worldwide, forests and urban trees provide important ecosystem services as well as economic and social benefits, but are threatened by non-native insects. More than 450 non-native forest insects are established in the United States but estimates of broad-scale economic impacts associated with these species are largely unavailable. We developed a novel modeling approach that maximizes the use of available data, accounts for multiple sources of uncertainty, and provides cost estimates for three major feeding guilds of non-native forest insects. For each guild, we calculated the economic damages for five cost categories and we estimated the probability of future introductions of damaging pests. We found that costs are largely borne by homeowners and municipal governments. Wood- and phloem-boring insects are anticipated to cause the largest economic impacts by annually inducing nearly

An Integer Optimization Approach to a Probabilistic Reserve Site Selection Problem

1.7 billion in local government expenditures and approximately

Optimal surveillance and eradication of invasive species in heterogeneous landscapes.

830 million in lost residential property values. Given observations of new species, there is a 32% chance that another highly destructive borer species will invade the U.S. in the next 10 years. Our damage estimates provide a crucial but previously missing component of cost-benefit analyses to evaluate policies and management options intended to reduce species introductions. The modeling approach we developed is highly flexible and could be similarly employed to estimate damages in other countries or natural resource sectors.

Causes and Implications of Species Restoration in Altered Ecosystems

Interest in protecting natural areas is increasing as development pressures and conflicting land uses threaten and fragment ecosystems. A variety of quantitative approaches have been developed to help managers select sites for biodiversity protection. The problem is often formulated to select the set of reserve sites that maximizes the number of species or ecological communities that are represented, subject to an upper bound on the number or area of selected sites. Most formulations assume that information about the presence or absence of species in the candidate sites is known with certainty. Because complete information typically is lacking, we developed a reserve selection formulation that incorporates probabilistic presence-absence data. The formulation was a discrete 0/1 optimization model that maximized the number of represented vegetation communities subject to a budget constraint, where a community was considered represented if its probability of occurrence in the set of selected sites exceeded a specified minimum reliability threshold. Although the formulation was nonlinear, a log transformation allowed us to represent the problem in a linear format that could be solved using exact optimization methods. The formulation was tested using a moderately sized reserve selection problem based on data from the Superior National Forest in Minnesota.

Not Getting Burned: The Importance of Fire Prevention in Forest Management

Cost-effective surveillance strategies are needed for efficient responses to biological invasions and must account for the trade-offs between surveillance effort and management costs. Less surveillance may allow greater population growth and spread prior to detection, thereby increasing the costs of damages and control. In addition, surveillance strategies are usually applied in environments under continual invasion pressure where the number, size and location of established populations are unknown prior to detection. We develop a novel modeling framework that accounts for these features of the decision and invasion environment and determines the long term sampling effort that minimises the total expected costs of new invasions. The optimal solution depends on population establishment and growth rates, sample sensitivity, and sample, eradication, and damage costs. We demonstrate how to optimise surveillance systems under budgetary constraints and find that accounting for spatial heterogeneity in sampling costs and establishment rates can greatly reduce management costs.

WEIGHING CONSERVATION OBJECTIVES: MAXIMUM EXPECTED COVERAGE VERSUS ENDANGERED SPECIES PROTECTION

gered Species Act of 1973 one year after passage. Since that time, natural recolonization and population recovery of wolves in the western Great Lakes region of the United States (the Lake States-Minnesota, Wisconsin, and Michigan) has been a notable success of the Act (Refsnider 1994). At the time of listing, the wolf was extirpated throughout the United States outside Alaska except for remnant populations in northeast Minnesota and on Isle Royale, in Lake Superior (Mech 1970). Since protection under the Act, the wolf population has in-

The influence of satellite populations of emerald ash borer on projected economic costs in U.S. communities, 2010-2020.

We extend existing stand-level models of forest landowner behavior in the presence of fire risk to include the level and timing of fuel management activities. These activities reduce losses if a stand ignites. Based on simulations, we find the standard result that fire risk reduces the optimal rotation age does not hold when landowners use fuel management. Instead, the optimal rotation age rises as fire risk increases. The optimal planting density decreases. The level of intermediate fuel treatment, but not its timing, is sensitive to the magnitude of fire risk. Cost-sharing is shown to be an effective instrument for encouraging fuel treatment. (JEL Q23)

Comparing extinction risk and economic cost in wildlife conservation planning

Decision makers involved in land acquisition and protection often have mul- tiple conservation objectives and are uncertain about the occurrence of species or other features in candidate sites. Models informing decisions on selection of sites for reserves need to provide information about cost-efficient trade-offs between objectives and account for incidence uncertainty. We describe a site selection model with two important conser- vation objectives: maximize expected number of species represented, and maximize the likelihood that a subset of endangered species is represented. The model uses probabilistic species occurrence data in a linear-integer formulation solvable with commercial software. The model is illustrated using probabilistic occurrence data for 403 terrestrial vertebrates in 147 candidate sites in western Oregon, USA. The trade-offs between objectives are explicitly measured by incrementally varying the threshold probability for endangered species representation and recording the change in expected number of species represented. For instance, in the example presented here, we found that under most budget constraints, the probability of representing three endangered species can be increased from 0.00 (i.e., no guaranteed protection) to 0.90 while reducing expected species representation ;2%. However, further increasing the probability of endangered species representation from 0.90 to 0.99 results in a much larger reduction in species representation of ;14%. Although the numerical results from our analysis are specific to the species and area studied, the meth- odology is general and applicable elsewhere.

Deploying wildland fire suppression resources with a scenario-based standard response model

The invasion spread of the emerald ash borer (Agrilus planipennis Fairmaire) (Coleoptera: Buprestidae) is characterized by the formation of satellite populations that expand and coalesce with the continuously invading population front. As of January 2010, satellite infestations have been detected in 13 states and two Canadian provinces. Understanding how newly established satellite populations may affect economic costs can help program managers to justify and design prevention and control strategies. We estimate the economic costs caused by EAB for the 10-yr period from 2010 to 2020 for scenarios of fewer EAB satellite populations than those found from 2005 to 2010 and slower expansion of satellite populations found in 2009. We measure the projected discounted cost of treatment, removal, and replacement of ash trees (Fraxinus spp.) growing in managed landscapes in U.S. communities. Estimated costs for the base scenario with the full complement of satellites in 2005-2010 and no program to mitigate spread is

Estimating the economic value of cultural ecosystem services in an urbanizing area using hedonic pricing

12.5 billion. Fewer EAB satellites from 2005 to 2010 delay economic costs of