Use of GIS to Assess the Impact of the Endangered Species Act on Pesticide Use

Background

About 65 percent of native mussel populations, such as Curtis pearly mussel and Pink mucket pearly mussel in the Little Black River of Missouri, have disappeared since 1980. Factors contributing these losses include channelization, water pollution, sedimentation, removal of stream gravel, declining fish populations and use of agricultural pesticides. In an effort to reduce adverse effects of agricultural pesticides on mussels, the U.S. Environmental Protection Agency (EPA) restricted the use of thiobencarb in the vicinity of the Little Black River and Current River in Ripley county, Missouri. Thiobencarb is an important herbicide for controlling barnyardgrass in rice production. EPA restrictions on thiobencarb can have a negative effect on the profitability of rice production.

Objectives

1. Develop maps showing the area within Missouri counties where pesticide use should be banned or limited to protect endangered or threatened species as determined by EPA.
2. Evaluate the economic feasibility of alternative weed management strategies designed to offset the potential negative effects on rice production in Ripley county, Missouri of EPA restrictions on thiobencarb.

Methods

• Objective 1. Paper maps developed by EPA and reviewed by the Missouri Department of Agriculture were used as a template to develop custom geographic information system (GIS) layers. These layers were then used to create maps which identified areas with endangered or threatened species by a shaded pattern.
• Objective 2. Stochastic dominance with respect to a function (SDWF) was used to evaluate the profitability of five alternative weed management strategies which utilize substitutes for thiobencarb. The SDWF analysis identified the efficient weed management strategies and ranked the strategies for different risk preferences.

Major Findings

• The 32 counties in Missouri which are affected by EPA's pesticide restrictions contain one or more of the following species: fat pocketbook mussel, Pink mucket pearly mussel, Curtis pearly mussel, Niangua darter, Missouri bladderpod and Ozark cavefish.
• The SDWF results indicated that applying only propanil after an economic weed threshold is exceeded dominates all other strategies for all three risk preferences because it has the highest average net return and a low variance. Net return per acre was actually higher with the dominant weed management strategy (propanil alone) than in the baseline (without restrictions on thiobencarb). Strategies with an economic threshold always dominated the corresponding strategies without a threshold. Therefore, IPM strategies using a threshold are dominant.
• Overall, the EPA policy of restricting thiobencarb to protect endangered mussels in Ripley county does not appear to have an adverse economic effect on rice production because using propanil alone with an economic threshold dominates weed management strategies that use thiobencarb. Propanil alone provides even greater net returns than using Thiobencarb. A possible negative short-run effect of the EPA restriction on thiobencarb is that it might lead to 'overuse' of propanil.

Major Products

A set of 32 8.5" x 11" black and white maps were developed which illustrate the habitat for the six endangered species in Missouri.

Publications

Lin, Cho-Min and Tony Prato. Evaluation of Economic Impacts of Endangered Species Protection on Rice Production in Ripley County, Missouri. Research Report No. 18, Center for Agricultural, Resource and Environmental Systems, University of Missouri-Columbia, October 1995.

Lin, Cho-Min. Economic Analysis of Weed Management Strategies under Uncertainty - A Decision Making Framework. PhD dissertation, Department of Agricultural Economics, University of Missouri-Columbia, Columbia, MO, 1995.

Investigators: Cho-Min Lin, Tony Prato and Steve Vance

Funding Amount: $20,451

Funding Source: U.S. Department of Agriculture

Project Duration: July 1993 - June 1995