Aquatic Plant Research > Scientific Data on Aquatic Plant Communities > Wisconsin Standard Method to Collect Aquatic Plant Data > Testing the Standard Method
Aquatic Plant Research
Testing the Standard Method
Before settling on one standardized plant sampling method, DNR Science Services performed extensive methodological testing to ensure the collected data would be usable in comparisons across time and across space. We tested, refined, and published information on the method prior to implementing the approach statewide.
DNR Science Services studied lakes over time to understand natural variability in seasonal growth patterns of aquatic plants. They measured aquatic plant frequency and biomass of all plants present in two lakes every two weeks over the course of 1.5 years. This work shows when surveys are the most representative of the plant community, and defined the ideal sampling window for aquatic plants in southern WI to be mid-June through the end of September. In northern WI, the sampling window is early July through mid-August. Annual plants (those that sprout each year from seeds) will be completely missed if the survey is too early or late. Sampling for curly-leaf pondweed is best done during May and June. Researchers found that biomass peaks as late as October for some species. The current sampling protocol suggests surveys should be taken in early July - mid August; this work suggests this can be expanded for southern Wisconsin.
Recognizing a need for quantitative baseline data on aquatic aquatic plant communities in lakes and flowages across the state, DNR Science Services have created a dataset of aquatic plant community point-intercept survey data on >300 lakes and flowages from 2005-present. Collecting and providing baseline survey data creates context to which other lakes can be compared across time and space, and allows for an improved understanding of the variation in aquatic plant communities across the state.
When we first established the point-intercept method as the standard approach to sampling aquatic plants in Wisconsin, researchers needed to know the nuts and bolts details-- for instance, how many samples should we take to accurately count the number of different species present? Did the size of the lake or the complexity of the shoreline affect how we should distribute the sampling points? To make sampling as efficient and powerful as possible, we conducted a detailed analysis of the point-intercept sampling method. One of the key points of this peer-reviewed paper specifies the level of effort needed to accurately capture aquatic plant data in a way that allows for scientifically sound comparisons. The paper can be found at: http://www.tandfonline.com/eprint/hdtdmcxWujXZawfhycgI/full