Spatial considerations in the economics of prevention and control of biological invasions.

摘要

Introductions of biological invaders are often a consequence of economic activity or human action. Invasive species and pathogens pose significant threats to both the environment and society. Preventing and managing invaders is an interdisciplinary problem; it cannot be achieved solely through use of economic analysis nor just consideration of system biology or ecology. Human action and the environmental responses are interconnected and should be studied as such. Proper specification of models to address prevention and management require an understanding of species biology and system ecology, which are both influenced by human and environmental factors.;This dissertation presents three essays on the economics of prevention and management of biological invasions with an emphasis on how space plays a role in introduction drivers and damage magnitudes. The questions addressed herein require consideration of biological, ecological, and economic processes to inform prevention and control policy. The first two essays explore the consequences of ignoring health risks resulting from land use change over time and space. The third essay addresses producer response to heterogeneous contamination risk in live animal input markets.;The concept that a number of infectious diseases such as malaria, Ebola, and Zika virus are linked to changes in anthropogenic land use is becoming widely known and accepted. However, infectious disease is rarely considered as a cost in land use decision-making. Chapter 1 develops a model that includes the health consequences of land conversion decisions. A dynamic harvest model is used to determine an optimal rate and area of land conversion that accounts for the benefits and consequences of environmental conversion, including increased prevalence of malaria. Simulations indicate the cost of ignoring the change in malaria prevalence as a consequence of land use change can create significant welfare losses and that this ignored cost of conversion should be factored into policy making.;The second chapter builds on the results of Chapter 1; health consequences arising from land use change are great enough to alter the net benefits of land conversion. Chapter 2 addresses whether risk of infectious disease modifies the optimal patterns and timing of land conversion. The dynamic model developed in this chapter allows for different time paths and areas of conversion across land units or regions, where any differences in conversion patterns are driven by spatial orientation of the land units. When the costs of infectious disease are correlated with patterns of land conversion, the optimal sites of land conversion are altered. Location of conversion can be used as a first step in mitigating health risks of altered landscapes and the patterns are dependent on magnitude of the disease costs. The results of this chapter are consistent with recommendations of ecologists and epidemiologists to strategically select conversion patterns by considering the ecological impacts of land use decisions.;Chapter 3 models producer response to information about contamination risk in live animal import markets. Trade and movement of live animals and animal products drive the introduction and spread of a number of zoonotic and livestock diseases. Existing trade policies are geared toward minimizing the risk of introducing a pest or pathogen by banning imports from specific sources. Understanding how agents behave in a decentralized environment can give insight into how to create targeted policies for minimizing risk. The model examines the trade-offs faced by importers when choosing where to source live and risky inputs to production. Simulations using data from the live cattle trade industry give insight into how and when importers substitute away from high-risk sources. The magnitude of substitution varies by the amount of information the importer uses in its risk estimation. The value to risk trade-off can be measured as an elasticity, detailing how individual producers respond to risk. Simulations indicate providing producers with more detailed information sets to determine the expected damages of import decisions reduces system costs and improves welfare over strict bans on trade.