Bioassays: The role of seed bank monitoring in range management

Authors: Clements, Darin - Charlie; Harmon, Daniel - Dan; FREESE, MARK - Society For Range Management

Submitted to: Society for Range Management Meeting Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: 11/4/2019
Publication Date: 2/17/2020
Citation: Clements, D.D., Harmon, D.N., Freese, M. 2020. Bioassays: The role of seed bank monitoring in range management. Society for Range Management Meeting Abstracts. 73:104. February 16-20, 2020 Denver, CO.

Interpretive Summary: Managing the vast acreage of rangelands in the arid western United States, has become one of the great environmental challenges of the 21st century. The complexity of land stewardship requires a multitude of management actions and the cooperation and collaboration of multiple entities. One very important aspect to a good management plan is monitoring. Monitoring includes outcomes of management actions such as timing and intensity of use as well as range improvement practices. Standardized monitoring protocol such as Assessment, Inventory, and Monitoring (AIM) have become universally used to make rangeland management decisions. While this protocol includes virtually every aspect of vegetation and soil stability characterization, if one searches for any reference to soil seed banks, you will find that it is not mentioned in the AIM manual. Seed banks represent one of the best predictors of future site potential and plant community condition and function. While resources such as Ecological Site Descriptions (ESD) and State and Transition models are often used to predict the best range improvement practices for a site, especially after a fire event, they represent a snapshot in time. Determining the level of cheatgrass competition seeded species will encounter the initial seedling establishment year is critical to make seed mix and rate decisions. We find that fall bioassay cheatgrass seed bank measurements are the best method to determine the level of competition seeded species will face. We will present various bioassay techniques we use to measure seedbanks in research and management activities. Data from our multiple research projects that use bioassays to measure seedbanks will be presented for reference. Bioassay seed bank results from herbicide treatments, soil nitrogen manipulations as well as perennial grass-cheatgrass suppression zones will be presented. Seed bank bioassays are a very efficient and effective tool to monitor and predict future cheatgrass populations.

Technical Abstract: Managing the vast acreage of rangelands in the arid western United States, has become one of the great environmental challenges of the 21st century. The complexity of land stewardship requires a multitude of management actions and the cooperation and collaboration of multiple entities. One very important aspect to a good management plan is monitoring. Monitoring includes outcomes of management actions such as timing and intensity of use as well as range improvement practices. Standardized monitoring protocol such as Assessment, Inventory, and Monitoring (AIM) have become universally used to make rangeland management decisions. While this protocol includes virtually every aspect of vegetation and soil stability characterization, if one searches for any reference to soil seed banks, you will find that it is not mentioned in the AIM manual. Seed banks represent one of the best predictors of future site potential and plant community condition and function. While resources such as Ecological Site Descriptions (ESD) and State and Transition models are often used to predict the best range improvement practices for a site, especially after a fire event, they represent a snapshot in time. Determining the level of cheatgrass competition seeded species will encounter the initial seedling establishment year is critical to make seed mix and rate decisions. We find that fall bioassay cheatgrass seed bank measurements are the best method to determine the level of competition seeded species will face. We will present various bioassay techniques we use to measure seedbanks in research and management activities. Data from our multiple research projects that use bioassays to measure seedbanks will be presented for reference. Bioassay seed bank results from herbicide treatments, soil nitrogen manipulations as well as perennial grass-cheatgrass suppression zones will be presented. Seed bank bioassays are a very efficient and effective tool to monitor and predict future cheatgrass populations.