Managing Woody Plant Encroachment to Restore Grassland Productivity in South Dakota

Commodities

Practices

Woody Plant Encroachment (WPE) was once believed to be confined to the Southern Great Plains, yet recent evidence shows that it is quickly spreading north and west. South Dakota is directly on the path of this expansion. Although the scale of WPE in South Dakota is currently lower than that in the Southern Plains, it is expanding at an accelerated rate due to factors such as fire suppression and favorable climatic conditions. The increase in woody plant cover reduces forage production and jeopardizes the survival of most grassland birds, and if not controlled, further raises wildfire risks, decreases water infiltration, and contributes to long-term rangeland degradation.

Strategic and proactive control measures at an early stage are necessary to achieve desirable effects in controlling the spread of woody species. To effectively suppress WPE in South Dakota, it is critical for ranchers to understand the WPE problem and different control strategies before it progresses to the heavily infested stage. While different control strategies have been proposed, it remains largely unknown how these strategies promote vegetation and forage recovery. Furthermore, the cost effectiveness of WPE control strategies has not been evaluated, leaving ranchers without the necessary guidance needed to make informed management decisions.

The proposed research intends to achieve the goal of reviving productive grassland production in South Dakota through interdisciplinary efforts in ecosystem measurement and economic analysis. Utilizing both data from field experiments and a producer survey, our project will achieve three objectives: 1) assess the post-treatment effects of different control strategies, namely herbaceous vegetation re-establishment, forage production change, and optimal grazing timelines; 2) understand the profitability change associated with different WPE control strategies; and 3) identify factors that affect adoption of WPE control practices.

This project seeks to generate timely, region-specific scientific evidence that will support proactive management strategies among grassland operators in South Dakota. Through this project, producers will gain practical knowledge of WPE control strategies, including how to implement them, what outcomes to expect, and how to evaluate their net financial impacts using partial budgeting. Research findings of this project will also support the development of targeted outreach materials and policy interventions to support broader, more coordinated efforts to curb woody plant encroachment. In the longer term, we expect to see more ranchers implement WPE control strategies, leading to restoration of grassland acres, increase in livestock production, improvement in ecosystem variety, and increase in grassland birds.

Learning outcomes:

• Improved understanding towards effect of WPE control strategies on the herbaceous vegetation regeneration and forage recovery.
• Enhanced producer awareness of WPE status and cost effectiveness of its control strategies.

Action outcomes:

• Increased outreach efforts by federal and state conservation agencies.
• Increased implementation of WPE control strategies and more proactive control measures by producers.

Condition change outcomes:

• Restored grassland acres and productivity.
• Improved forage production and grassland stocking capacity.
• Increased number of grassland birds
• Increased economic revenue from grazing cattle production and grassland bird hunting.

Regulation

• Availability of more government incentive programs that promote WPE control strategy adoption.