A review of aquatic plant monitoring and assessment methods

Authors: Madsen, John; WERSAL, RYAN - Lonza Corporation

Submitted to: Journal of Aquatic Plant Management
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/4/2016
Publication Date: 1/1/2017
Citation: Madsen, J.D., Wersal, R.M. 2017. A review of aquatic plant monitoring and assessment methods. Journal of Aquatic Plant Management. 55(1):1-12.

Interpretive Summary: One overlooked aspect of the NPDES general permit for pesticide application to water is the requirement for quantitative assessment of the level of weed impact, and the assessment of management efficacy and nontarget plant response. This publication provides an overview of relevant plant assessment methods for aquatic plants, and makes recommendations on which techniques are appropriate for various applications.

Technical Abstract: Aquatic plant management has become increasingly scrutinized by federal and state regulatory agencies, including the recent implementation of a NPDES permitting program in each state. Many states require documentation of nuisance acres, and an evaluation of management success. Despite this need, no widely accepted “standard methods” for quantifying nuisance plants has been published. We review the most commonly used quantitative methods for monitoring plant distribution, species composition, and abundance; and make general recommendations to support management activities in monitoring plant populations and assessing management efficacy. It is important to choose an appropriate method to meet the goals and objectives of a given program, and to be willing to change methods as the needs and objectives of the program change. It is unlikely that the same monitoring and assessment method will be used throughout a program, especially a long-term program. We recommend choosing methods that are 1) quantifiable, that is, data can be statistically analyzed, 2) follow an appropriate sampling design, and 3) are repeatable and flexible enough to change based on needs and personnel. Ideally, monitoring and assessment methods need to incorporate both target and non-target impacts, collect data that is objective and can be quantified, and is labor and cost effective.