Bayesian Decision Networks


A support tool for State Wildlife Action Plans

Research Summary

A STRUCTURED DECSION MAKING APPROACH TO SUPPORT A DEVELOPING STATE WILDLIFE ACTION PLAN: CONSERVATION OF PLAINS TOPMINNOW IN NEBRASKA
Investigators: David A. Schumann and Michael E. Colvin

Plains Topminnow Fundulus sciadicus are endemic to the Great Plains, and because of declines in their geographic range and local abundance are granted protection throughout their native range. A team of managers in Nebraska are developing a State Wildlife Action Plan, the first for an aquatic taxon in the state, to inform the species’ conservation. In support of this conservation initiative, we developed a Bayesian decision network model to help decision makers identify appropriate and cost-effective methods to manage stream reaches to maximize topminnow persistence. Our model predicts the relative influence of competing management alternatives (e.g. reintroduction, riparian management, barrier removal, etc.) on future topminnow occupancy using biological, chemical, and physical criteria thought to influence the species. Model nodes are informed by empirical data, published reports, and expert judgement. This decision support tool integrates the collective effects of these criteria and uncertainty on Plains Topminnow occupancy and evaluates tradeoffs among management alternatives at each stream reach a biologist visits. Biologists can now promptly identify optimal management actions and best allocate limited resources to maximize topminnow persistence. We have mobilized a conservation plan to reach transparent and defensible management decisions; a process relevant to diverse taxa of conservation significance.

Click the button for a video turtorial that introduces the structure decision making process and describes the Bayesian decision network developed to support this conservation initiative.

PTM Decision Network Video

BAYESIAN DECISION NETWORK

Figure 1. The alpha level Bayesian decision network model developed in coordination with the Plains Topminnow working group (Nebraska Game and Parks Commission). This model estimates the probability that Plains Topminnow will persist at the managed stream reach given the conservation alternatives (i.e. reintroduction, riparian rehabilitation, etc.) and the current condition of the stream reach. Numerous factors thought to influence the species (i.e. turbidity, presence of invasive species, sinuousity, etc.) are accounted for, but the model also considers the relative cost of each management alternative. Descriptions of the node states and conservation alternatives can be found below.

Objective: To maximize local population persistence of Plains Topminnow throughout Nebraska by applying cost-effective management strategies

Status: Alpha model
Collaborators: Mississippi State University & Nebraska Game and Parks Commission

Bayes Net (Alpha model)

PROBLEM STATEMENT
Plains Topminnow, a species of greatest conservation need in Nebraska, has declined dramatically throughout its native range; however, the reasons for decline are poorly understood. This species is a priority for management by the Nebraska Game and Parks Commission (NGPC), but currently lacks an organized management plan to inform decisions. A method is needed to decide where conservation should be conducted and the specific management actions to use. This framework will provide a standardized template for conservation planning and the development of SMART objectives for other at-risk species. Although NGPC has a responsibility for stewardship of natural resources in the state and controls management of some land, it has limited legal authority to allocate water. This agency and other related stakeholders (landowners, irrigation districts, etc.) will use this template plan to inform opportunistic management of Plains Topminnow at individual stream reaches throughout the historical range of the species in Nebraska.

Status: Draft

ALTERNATIVE MANAGEMENT STRATEGIES
The proposed conservation strategies to support the persistence of Plains Topminnow in individual stream reaches throughout the State of Nebraska.

Conservation Action Relative Cost Definition
Riparian Rehabilitation Moderate Restoration of riparian habitats to indirectly improve instream abiotic conditions
Channel Alteration High Instream alterations to increase the avilablity of habitats important to topminnow survival/reproduction
Biotic Renovation Moderate Renovation to physically remove or deter the introduction of species that influence topminnow survival
Reintroduction Low Addition of adult topminnow to influence future site occupancy
Add/Remove Barriers Very High Removal of barriers that fragment topminnow populations or addition to deter the establishment of negative species
No Action Very Low No individual management action stands out given the current stream conditions

Click the button for a video turtorial that introduces the structure decision making process and describes the Bayesian decision network developed to support this conservation initiative.

PTM Decision Network Video