Date of Award

8-2011

Level of Access

Campus-Only Thesis

Degree Name

Master of Science (MS)

Department

Resource Economics and Policy

Advisor

Kathleen P. Bell

Second Committee Member

Mario F. Teisl

Third Committee Member

Jessica E. Leahy

Abstract

These empirical papers explore economic decision-making at several scales of lake and watershed management, including a state-wide environmental trend analysis and a focused study of individual behavior in select watersheds. Two nationally-relevant topics in lake management entailing significant interplay between economic and environmental systems are discussed: the spread of invasive species and the role of individual households in polluted runoff. While the following analyses address different ecological issues, they are linked by a shared goal of advancing the use of economic tools in addressing efficient environmental policy design. The first paper draws on a substantial invasive aquatic plant modeling literature to describe patterns of invasive aquatic plants across a lake-rich landscape. We contribute to a body of this literature which systematically addresses a natural resource manager's strategy in developing an invasive plant control strategy that efficiently allocates resources across two competing alternatives: those which mitigate risk of the invasion (e.g., prevention) and those which improve preparedness for post-invasion control. Conceptually, information about relative risks of invasion can improve lake managers' ability to weight relative costs and benefits of alternative control strategies. As invasive aquatic watermilfoil is of particular concern in Maine, this paper contributes an empirical perspective on Maine lakes' relative risk of invasion by this species. The analysis also provides an empirical update of prior work which ranked Maine lakes' vulnerability to any invasive aquatic plant. Given this and other prior work, we describe invasive aquatic watermilfoil presence using lake and landscape characteristics such as lakes' volume of use, proximity to nearby invasions, colonization potential and watershed land use. Results of our logistic regression suggest the most reliable predictors of presence in Maine lakes are exposure-based. Growth-mediating variables impact establishment but may not be consistent predictors of detectable invasions in Maine. Our results support current policy choices in Maine and suggest new opportunities for regional invasive aquatic plant management. The second paper develops and tests a model of household decisions to adopt conservation practices that reduce residential storm water pollution. This research draws upon a line of inquiry combining economic and psychological insights to model pro-environmental behavior. We investigate the roles of social norms, positional status and additional social-psychological determinants in revealing cognitive and economic motivations related to household use of shoreline buffers of vegetation and regular septic system maintenance. We estimate discrete choice models of both past and intended future behavior using data from a mixed-mode survey of Maine lakefront property owners. Our results highlight payoffs in blending multi-disciplinary insights and suggest the relative importance of economic and psychological motivations varies across practices providing different proportions of public and private returns. Implications are discussed for lake water quality protection programs employing social rewards to motivate lake stewardship.

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