Estimating the Costs of Protecting Native Species from Invasive Animal Pests in New South Wales,Australia

Invasive animal pests reduce crop and livestock output, require management and control measures, and threaten native plants, animals and their habitat. The agricultural and management costs are often directly measurable. But the costs to protect threatened native plants and animals are harder to assess. The Rural Lands Protection Boards were the government agency in New South Wales that managed invasive animals. An analysis of their decisions provided the opportunity to estimate the costs of protecting native species. The number of native plants and animals threatened by invasive pests was modelled against the expenditure, area, pest abundance, climate and location of 38 Board districts. There was a strong negative relationship between the number of threatened native species and Board expenditure. This relationship was interpreted to estimate the marginal cost of protecting a threatened native species, the downward shift in the supply curve necessary to protect all threatened native species, and the gains from the shift in the form of cost savings in the continued protection of non-threatened native species. These results value some of the costs that invasive animal pests impose on the environment.     

An options based bioeconomic model for biological and chemical control of invasive species

The management of non-native invasive species is a complex but crucial task given the potential for economic and environmental damages. For many invasions the development of socially optimal control strategies requires more than is offered by the single-species, single-control models that have dominated this area of research. We develop a general stochastic optimal control framework that accommodates multiple interacting species while accounting for uncertainty in the temporal population dynamics. This extension to the current line of bioeconomic control models allows for the design of optimal integrated pest management strategies that utilize both chemical and biological controls in an environment of uncertainty and irreversibility. We demonstrate the benefits of combining chemical and biological controls in long term management strategies through a case study of the hemlock wooly adelgid (Adelges tsugae) infestation in the eastern United States. In this application we find that the introduction of natural predators is usually sufficient to manage the infestation, though chemical insecticides can play an important role when detection of the infestation is delayed or when the biological control agent does not sufficiently increase mortality of the invasive species.     

The economics of biotechnology under ecosystem disruption

Economic analysis of chemical pesticide use has shown that the interactions between plants, pests, damage control technology and state of the ecosystem are important variables to be considered. Hence, a bio-economic model was developed for the assessment of Bt variety and pesticide-based control strategies of the cotton-bollworm in China. The model simulates plant growth, the dynamics of pest populations and of natural enemies. The model predictions are used as major inputs for a stochastic micro-level profit model of alternative control strategies.Results show that: (1) productivity effects of Bt varieties and pesticide use depend on the action of natural control agents, and (2) the profitability of damage control measures increases with the severity of ecosystem disruption. The findings highlight the importance of the choice of the counterfactual scenario in the assessment of the impact of agricultural biotechnology. Also, some doubts are raised whether the high benefits of Bt cotton varieties claimed by previous studies based on cross section comparisons are realistic.     

Coevolution of economic and ecological systems

This paper analyzes a model of economy–environment coevolution in which economic activities induce the genetic evolution of a biological species. This model is applied to the problem of pesticide resistance management. Just as in Munro (Environ Resour Econ, 9:429–449, 1997), we consider three main types of interactions: (1) a large pest population reduces economic revenues, (2) economic activities select for resistant genes and (3) the spread of resistant genes affects the size of the pest population. The model differs from Munro in that it includes evolutionary modeling of economic strategies. Economic agents are assumed to be boundedly rational, i.e they cannot compute the optimal level of pesticide use that minimizes resistance among pests. Economic evolution represents the change in the distribution of pesticide strategies in the population of economic agents and is modeled by a replicator dynamics equation. The interactions between economic evolution of pesticide strategies, pest population dynamics and genetic evolution of resistance of pests are studied in a system of three differential equations. We explore the dynamics and stability properties of the system using numerical simulations.     

WATER BANKING AND RESTORATION OF ENDANGERED SPECIES HABITAT: AN APPLICATION TO THE SNAKE RIVER

Most river basins have experienced development of water projects to promote flood control, recreation, and hydropower and agricultural production. Though the projects helped establish stable economies, there have been adverse impacts to the natural environment and wildlife that reside in these river basins. One of the key policy tools for habitat restoration is management of instream flows. Alternative water banking policies for restoring habitat are compared using a spatial optimization model to identify which policies work best to augment instream flows for habitat restoration. Results indicate that policy goals dictate what type of water bank is preferred.     

The Asian clam Corbicula fluminea in the European freshwater-dependent industry: A latent threat or a friendly enemy?

While the biofouler Corbicula fluminea (Müller, 1774) is known to cause great economic losses in North America, studies reporting the problem in Europe are much scarcer. This paper explores the industrial effects of the species in Portugal, the gateway by which the bivalve entered Europe around 30 years ago. National waterworks, major power stations, cement plants, pulp and paper mills and irrigation systems were surveyed. The industrial impacts of the pest were shown to remain relatively mild; irrigation systems are those that seem to be facing more significant economic losses due to infestation. Possible reasons for the apparent discrepancy between this result and the species dispersal in natural ecosystems are discussed, and recommendations on adequate responses to the latent threat are provided. This study may assist the implementation of integrated pest management policies in countries at risk of invasion or recently invaded, and contribute to an understanding of the species’ progression in industrial environments.     

Bang for buck: cost-effective control of invasive species with different life histories

Strategies for controlling invasive species can be aimed at any or all of the stages in the life cycle. In this paper, we show how to combine biological data on population dynamics with simple economic data on control costs options to determine the least costly set of strategies that will prevent an established invader from continuing to increase. Based on biological data alone (elasticities of matrix population models), effective control strategies are sensitive to both life history and rate of population growth. Adding economic considerations, however, can cause the optimal control strategy to shift, unless the costs of intervention are the same across life stages. As an example, we apply our methods to oyster drills (Ocinebrellus inornatus), an economically important aquaculture pest that has been accidentally introduced worldwide. Control efforts are applied to local tidelands through manual removal of adults, although the life history characteristics of the species indicate a low population elasticity for adult survival. Aquaculturists are making bioeconomic decisions to remove adults vs. egg capsules, because of the relative ease of controlling each stage.     

Mitigation and adaptation strategies for the control of biological invasions

Biological invasions are recognised to be a problem of growing severity. Human pathogens, weeds or pests in terrestrial systems and dominant alien species in freshwater or marine aquatic systems all impose significant costs in terms of forgone output or costs of control in every major system. Like many of the other environmental consequences of globalisation, biological invasions require that decisions be taken under uncertainty. Decision-makers in such circumstances have to choose between two main strategies: mitigation and adaptation. This paper characterises invasive species problems in terms of the properties of the stochastic processes they induce. It considers how mitigation and adaptation strategies may be modelled, and identifies the conditions in which each approach may be efficient and effective.     

A real option approach to the protection of a habitat dependent endangered species

We use a real option approach to determine when a social planner has to stop or resume logging in situations where an endangered species relies on forest habitat for its survival. Logging affects the stochastic process followed by the habitat of the endangered species, which disappears irreversibly if its habitat reaches a critical extinction level. As long as the endangered species is still in existence, the social planner manages logging in such a way as to balance the risk of extinction against the benefits from commercial wood exploitation. The model incorporates economic, ecological, and social features. It is solved analytically to characterize the optimal forest management rule. Then it is applied to the case of the Rangifer tarandus caribou, an endangered species in Central Labrador (Canada). The parameters of the habitat process are estimated by Monte Carlo methods. The policy implied by the model – alternatively banning and resuming logging according to appropriate habitat threshold levels – turns out to be quite attractive; it does not require long banning periods while it drastically reduces the extinction risk and increases forest value.     

Preference Heterogeneity in the Structural Estimation of Efficient Pigovian Incentives for Insecticide Spraying to Reduce Malaria

This paper bridges the theoretical and empirical literatures on the role of preference heterogeneity in characterizing externalities related to disease transmission. We use a theoretical structure similar to locational sorting models, which characterize equilibria in terms of marginal individuals who are indifferent between locations. In our case, the ‘locations’ are binary, consisting of whether or not to take a discrete preventative action. Individual heterogeneity arises in this structure due to variation in the costs and disutility associated with prevention. We demonstrate application of this approach in the context of participation in insecticide-based indoor residual spraying programs for malaria control in northern Uganda. We identify the parameters of our theoretical model using a stated preference choice experiment combined with estimates from published epidemiological studies. The model implies that Pigovian subsidies for participation in this context should decrease household malaria risk by 19–25%. Our approach can be applied to other bioeconomic externalities with spillovers from discrete preventative actions, including agricultural pest management and the control of pest infestations and invasive species.     

由单一走向多样：平原农业区生物多样性 保护的规划途径——以辽宁省黑山县为例

平原农业区的生产和土地利用方式严重影响区域的 生物多样性,利用融合多学科的景观空间规划构建有效的评价 方法和格局优化模式以实现多样化的生境保护和恢复,提升生 物多样性具有重要的作用。以辽宁省黑山县为例,首先梳理了 平原农业区对于生物多样性威胁的机制和研究的框架;其次识 别平原农业区的特殊生境类型,使用景观格局指数和InVEST 模型的生境质量评价构建多尺度生境质量评价机制;同时使用 基于图论和电路理论的Linkage Mapper软件,识别和分级 空间中的重要生态源地、潜在廊道及廊道上的关键夹点区域。 结果显示,农业景观中空间异质性和连接性影响生物多样性; 研究区有主要生境23类,整体生境质量较差,农田面积较大 是造成该问题的主要原因;识别出核心斑块33个,重要廊道 34条,通过与卫星图比照,廊道位置与线性生境重合;关键 夹点区域位于靠近农村居民点的自然生境上,故营造人类干扰 与生态平衡农村居住区是空间规划的重点;同时根据以上研究 提出了多尺度的空间规划途径,为平原农业区生境优化和生物 多样性保护提供了一定的理论参考。     

Managing invasive alien species with professional and hobby farmers: Insights from ecological-economic modelling

Biosecurity is a great challenge to policy-makers globally. Biosecurity policies aim to either prevent invasions before they occur or to eradicate and/or effectively manage the invasive species and diseases once an invasion has occurred. Such policies have traditionally been directed towards professional producers in natural resource based sectors, including agriculture. Given the wide scope of issues threatened by invasive species and diseases, it is important to account for several types of stakeholders that are involved. We investigate the problem of an invasive insect pest feeding on an agricultural crop with heterogeneous producers: profit-oriented professional farmers and utility-oriented hobby farmers. We start from an ecological-economic model conceptually similar to the one developed by Eiswerth and Johnson [Eiswerth, M.E. and Johnson, W.S., 2002. Managing nonindigenous invasive species: insights from dynamic analysis. Environmental and Resource Economics 23, 319-342.] and extend it in three ways. First, we make explicit the relationship between the invaded state carrying capacity and farmers' planting decisions. Second, we add another producer type into the framework and hence account for the existence of both professional and hobby farmers. Third, we provide a theoretical contribution by discussing two alternative types of equilibria. We also apply the model to an empirical case to extract a number of stylised facts and in particular to assess: a) under which circumstances the invasion is likely to be not controllable; and b) how extending control policies to hobby farmers could affect both types of producers.     

A bioeconomic model for determining the optimal response strategies for a new weed incursion

Invasions by non-indigenous plant species pose serious economic threats to Australian agricultural industries. When a new invader is identified a rapid response is critical, particularly if the invasive species has the ability to spread rapidly. An early decision is required whether to attempt to eradicate or contain the infestation, or do nothing and leave it to landholders to manage. These decisions should be based on economic considerations that account for long term benefits and costs. This paper describes a bioeconomic simulation framework with a mathematical model representing weed spread linked to a dynamic programming model to provide a means of determining the economically optimal weed management strategies over time, from the government’s perspective. The modelling framework is used to evaluate hypothetical case study invasive weed control scenarios in the Australian cropping systems. The benefit–cost ratios of invasion control are shown to be generally very high and clearly, there are significant benefits to be achieved by controlling highly invasive weeds when initial infestations are at a low level. Even if the invasion cannot be eradicated due to its high invasiveness or budget constraints, it still pays to maintain invasions at low levels.     

How trade politics affect invasive species control

Trade has become the main mode of transport for many invasive species, including diseases and agricultural pests. Most species are brought to their new homes unintentionally, which constitutes a market failure rooted in international trade. Unless it is practical to drive invasion risk to zero, the external costs may justify a tariff. In this paper, we analyze the political process likely to govern the formation of tariffs so justified using a straightforward incorporation of an invasive species externality into Grossman and Helpman's (GH) well-known political economy model. We show that our measure of disguised protectionism—the gap between the optimal tariff and that set in the equilibrium of the political economy game—is equal to the tariff that would be set if there were no invasive species and no international disciplines on trade policy. The informational needs required to distinguish disguised protectionism from legitimate public-goods protection are formidable.     

Economic modeling approaches for wildlife and species conservation

This paper presents modeling approaches for wildlife and species conservation with a special emphasis on large mammals in a developing country setting. In such countries there are frequently conflicts over land use and species conservation, and institutions for managing conflicts are often weak or even lacking. In addition, most of the world species and biodiversity are found in developing countries. Two main issues are discussed. First, we study a situation where the wildlife is valuable, but is considered a pest by the local people living close to the wildlife. Second, we consider models with a discrepancy between management geography and biological geography, and where the species flows between a conservation area with no harvesting and a neighboring area with harvesting and possible habitat degradation.     

The Control of Invasive Species on Private Property with Neighbor-to-Neighbor Spillovers

Invasive pests cross property boundaries. Property managers may have private incentives to control invasive species despite not having sufficient incentive to fully internalize the external costs of their role in spreading the invasion. Each property manager has a right to future use of his own property, but his property may abut others’ properties enabling spread of an invasive species. The incentives for a foresighted property manager to control invasive species have received little attention. We consider the efforts of a foresighted property manager who has rights to future use of a property and has the ability to engage in repeated, discrete control activities. We find that higher rates of dispersal, associated with proximity to neighboring properties, reduce the private incentives for control. Controlling species at one location provides incentives to control at a neighboring location. Control at neighboring locations are strategic complements and coupled with spatial heterogeneity lead to a weaker-link public good problem, in which each property owner is unable to fully appropriate the benefits of his own control activity. Future-use rights and private costs suggest that there is scope for a series of Coase-like exchanges to internalize much of the costs associated with species invasion. Pigouvian taxes on invasive species potentially have qualitatively perverse behavioral effects. A tax with a strong income effect (e.g., failure of effective revenue recycling) can reduce the value of property assets and diminish the incentive to manage insects on one’s own property.     

Identifying cost-effective hotspots for restoring natural capital and enhancing landscape multifunctionality

Much effort is expended toward planning for conservation, natural resource management and sustainable land use in agricultural landscapes. Although often not explicitly stated, the aims of these efforts are often to restore natural capital for the provision of ecosystem services and stimulate multifunctionality in landscapes. However, the scarcity of resources for, and the potential economic impact of, ameliorative actions that restore natural capital necessitates the identification of cost-effective geographic priorities, or hotspots, which provide multiple ecosystem goods and services. This requires the integrated spatial modelling of multiple environmental and economic processes accompanied by clear goals and performance indicators. Identification of hotspots provides guidance for highly targeted land use change that cost-effectively adds to the stocks of natural capital in a landscape. Additionally, the multifunctionality of the landscape can be increased through the provision of multiple ecosystem goods and services. This paper begins by examining data requirements for identifying geographic hotspots for land use change. This study integrates traditionally disparate landscape-scale biophysical and economic data and models. The elements of natural capital considered here are species and ecosystems, soil and water resources, and the atmosphere. It is demonstrated that locating ameliorative actions towards hotspots will be more cost-effective at restoring natural capital and stimulating landscape multifunctionality than a random targeting approach. We calculate these efficiencies using a small set of indicators for assessing aspects of multifunctionality. The focus of this study is the agricultural landscapes of the Lower Murray region of south-eastern Australia.     

Managing exotic pests under uncertainty: optimal control actions and bioeconomic investigations

Using a real options framework in continuous time, we examine two problems associated with the management of exotic pests under uncertainty. First, we analyze the optimal timing of investing in a control action. Given fixed control costs, we obtain a closed-form solution for when to control an exotic pest whose density varies randomly. Second, we define an analytical framework for finding the optimal expenditures for obtaining the relevant bioeconomic data. Our numerical results, based on a wide range of bioeconomic parameters, highlight the importance of accounting for uncertainty and irreversibility when developing simple rules to manage exotic pests.     

Farming system modelling for agri-environmental policy design: The case of a spatially non-aggregated allocation of conservation measures

This paper addresses the issue of designing policies for habitat conservation on agricultural land. The case under study requires a non-aggregated spatial distribution of the fields to be enrolled in an agri-environmental programme. A spatially explicit mathematical programming farm-based model, which accounts for three spatial levels (field, farm and landscape), is coupled with a relevant spatial pattern index (the Ripley L-function) to analyse the design and implementation of an agri-environmental programme aimed to preserve the Tetrax tetrax in the Plaine de Niort, France. The model is run using a stylised map with heterogeneous soil types and both crop growing and mixed dairy farms. Results show that valuable insights into agri-environmental programme design are gained through a detailed representation of farming system management. The suitable, non-aggregated spatial pattern for T. tetrax conservation is more costly than less-suitable, more aggregated patterns, because it tends to require equal participation of all farms. The policy simulations reveal that the various spatial patterns can be obtained through relatively simple uniform contract structures. An effective contract structure entails a set of two degressive payments which encourages all farms to enrol at least a small share of their land in the program.     

Spatial Management of Invasive Species: Pathways and Policy Options

In addressing the problem of invasive species, decision makers have a variety of options, each targeting different aspects as it evolves over time and space. We develop a 2-region bioeconomic model that includes several transmission pathways that spread the invader. Within each region, inspections, removal efforts, and sustainable land management practices, including habitat restoration and less damaging production activities, are available to the regulator. We investigate the implications of different transmission pathways and second-best policies on the control patterns and invasive populations. Second-best settings where certain controls are not available to the regulator result in large distortions on the optimal use of the land. Overall, we find that non-linear interactions between regions, pathways, and controls are significant determinants of the optimal management of invasive species.