Valuing bioeconomic impacts of regulation on nutrient loads mediated by invasive mussels in Lake Michigan.

Current calls to correct the perturbed ecosystems and nutrient imbalances of the Laurentian Great Lakes focus on setting target nutrient levels that will be met by environmental and economic regulations to reduce the flow of excess nutrients into the lakes. While these standard types of regulations have been successful in the past, it is unclear whether they will achieve similar ecological and economic successes now amid possible ecosystem regime shifts triggered by invasive mussels. We compute the bioeconomic costs and benefits of hypothetical regulations designed to target nutrient loads in present-day Lake Michigan through agricultural operations, which are known to be nonpoint source polluters of the aquatic ecosystem network.

A Best Practices Case Study for Scientific Collaboration between Researchers and Managers.

Effective engagement among scientists, government agency staff, and policymakers is necessary for solving fisheries challenges, but remains challenging for a variety of reasons. We present seven practices learned from a collaborative project focused on invasive species in the Great Lakes region (USA-CAN). These practices were based on a researcher-manager model composed of a research team, a management advisory board, and a bridging organization.

Potential establishment and ecological effects of bighead and silver carp in a productive embayment of the Laurentian Great Lakes.

Bighead carp . and silver carp (collectively bigheaded carps, BHC) are invasive planktivorous fishes that threaten to enter the Laurentian Great Lakes and disrupt food webs. To assess the likelihood of BHC establishment and their likely effects on the food web of Saginaw Bay, Lake Huron, we developed a multi-species individual-based bioenergetics model that tracks individual bighead and silver carp, four key fish species, and seven prey biomass groups over 50 years.

The geometry of reaction norms yields insights on classical fitness functions for Great Lakes salmon.

Life history theory examines how characteristics of organisms, such as age and size at maturity, may vary through natural selection as evolutionary responses that optimize fitness. Here we ask how predictions of age and size at maturity differ for the three classical fitness functions-intrinsic rate of natural increase r, net reproductive rate R0, and reproductive value Vx-for semelparous species. We show that different choices of fitness functions can lead to very different predictions of species behavior.

Rating impacts in a multi-stressor world: a quantitative assessment of 50 stressors affecting the Great Lakes.

Ecosystems often experience multiple environmental stressors simultaneously that can differ widely in their pathways and strengths of impact. Differences in the relative impact of environmental stressors can guide restoration and management prioritization, but few studies have empirically assessed a comprehensive suite of stressors acting on a given ecosystem. To fill this gap in the Laurentian Great Lakes, where considerable restoration investments are currently underway, we used expert elicitation via a detailed online survey to develop ratings of the relative impacts of 50 potential stressors.

Use of structured expert judgment to forecast invasions by bighead and silver carp in Lake Erie.

Identifying which nonindigenous species will become invasive and forecasting the damage they will cause is difficult and presents a significant problem for natural resource management. Often, the data or resources necessary for ecological risk assessment are incomplete or absent, leaving environmental decision makers ill equipped to effectively manage valuable natural resources. Structured expert judgment (SEJ) is a mathematical and performance-based method of eliciting, weighting, and aggregating expert judgments.

Out-of-sample validation for structured expert judgment of Asian carp establishment in Lake Erie.

Structured expert judgment (SEJ) is used to quantify the uncertainty of nonindigenous fish (bighead carp [Hypophthalmichthys nobilis] and silver carp [H. molitrix]) establishment in Lake Erie. The classical model for structured expert judgment model is applied.

Joint analysis of stressors and ecosystem services to enhance restoration effectiveness.

With increasing pressure placed on natural systems by growing human populations, both scientists and resource managers need a better understanding of the relationships between cumulative stress from human activities and valued ecosystem services. Societies often seek to mitigate threats to these services through large-scale, costly restoration projects, such as the over one billion dollar Great Lakes Restoration Initiative currently underway. To help inform these efforts, we merged high-resolution spatial analyses of environmental stressors with mapping of ecosystem services for all five Great Lakes.