Harvesting in an integrated general equilibrium model

Harvesting of prey biomass is analyzed in an integrated ecological-economic system whose submodels, a predator–prey ecosystem and a simple economy, are microfounded dynamic general equilibrium models. These submodels are interdependent because the ecosystem responds to harvesting—through the reactions of optimizing individual organisms—by changing the provision of public ecosystem services to consumers. General analytical results are derived regarding the impact of harvesting policies on short-run equilibria of both submodels, on population dynamics, and on stationary states of the integrated model. A key insight is that prey biomass carries a positive ecosystem price which needs to be added as a tax mark-up to the economic price of harvested biomass to attain allocative efficiency. Further information on the dynamics is gained by resorting to numerical analysis of the policy regimes of zero harvesting, laissez-faire harvesting and efficient harvesting.

It “... is a matter of weighing costs and benefits of taking action, whether the action is the “inert” one of leaving resources alone in order to conserve them, or whether it involves exploiting a resource ... for so-called material ends”. Pearce (1976, p. 320)

Helpful comments from an anonymous referee are gratefully acknowledged. Remaining errors are the authors’ sole responsibility.     

Governmental Control of Externalities,or the Prey Eats the Predator

This paper argues that Gunnar Myrdal's theory of the state fruitfully elucidates which set of factors contributed to the transformation of the Welfare State into what James K. Galbraith has described as the modern Predator State. Myrdal employs the circular cumulative causation hypothesis (Berger forthcoming; 2008; Berger and Eisner 2007) to explain the evolution of the state as the result of multiple interrelated factors. Myrdal's evolutionary-institutional analysis of the state is found to be compatible with Galbraith's (2008) recent Veblenian approach in that it highlights the role of corruption (pecuniary considerations) in the relationship between big business (the "organized sector") and government.     

Effectiveness and cost-effectiveness of yellow-eyed penguin recovery

Although an estimated US$6 billion is invested annually in our planet's biological diversity, little research has been conducted on which conservation treatments work best or provide best value for money. Where controlled experiments are not possible, econometric techniques can be used to determine the effectiveness of conservation treatments. We use a long-running yellow-eyed penguin (Megadyptes antipodes) nest count in New Zealand to compare the effectiveness and cost-effectiveness of three commonly used endangered species recovery treatments—trapping of introduced predators, revegetation, and intensive management. Following ecological theory, we specify a density-dependent population growth rate. We control for year effects and site characteristics such as land cover, slope, and elevation. The possibility of selection bias in treatment is confronted with site fixed effects and with an instrumental variable based on site accessibility. Of the three treatments that we analyze, only intensive management is significantly correlated with increases in annual site-level yellow-eyed penguin population growth rate. We estimate that intensive management increased the yellow-eyed penguin population by 9% above the counterfactual, and that the average cost of producing an additional yellow-eyed penguin nest through intensive management is NZ$68,600.     

Predator–prey dynamics in general equilibrium and the role of trade

We examine the implications of trade in an economy with two interrelated natural resources, focusing on the case of a simple predator–prey relationship. We derive a three-sector general equilibrium model where production functions are linked via the ecological dynamics of the natural system. Under autarky, this economy exhibits a steady-state equilibrium that overexploits the prey stock, reducing the linked predator population and overall welfare in the absence of harvesting controls. When two economies engage in trade, differences in the dynamics of the two resource systems can become the basis for comparative advantage. In this case, the predator–prey relationship leads to a source of comparative advantage in harvesting prey for a country with a lower autarky steady-state proportion of predators to prey. This feature has not been noticed in the literature and leads to a counterintuitive implication: free trade can help conserve predator and prey stocks in the country with the higher autarkic steady-state proportion of predators to prey. To illustrate the relevance of our analytic findings, we present the stylized empirical example of the effect of Chinook salmon imports on killer whale populations.