Author: R. Smith, M. Clymer

Author Affiliation: LCWC

Journal: Unpublished Report, 19 January 2019

Abstract:

An unprecedented dense growth of the highly invasive Eurasian watermilfoil (Myriophyllum spicatum) reached monoculture levels in Cedarville and Sheppard bays within the Les Cheneaux Islands (LCI) in 2011 and 2012. Dense patches of Eurasian watermilfoil (EWM) grew in over ten percent of other LCI waters during that time. The objective of this six-year study was to learn how EWM and other rooted aquatic plants (macrophytes) responded to the record EWM density of that period. Beginning in 2013, EWM density fell precipitously in both bays and remained at low levels for the remainder of the study. Based upon point-intercept analysis, growth density of other macrophytes common to these bays decreased, remained constant, or increased during the study period. Possible explanations for the dramatic EWM decline include: natural EWM life cycle, natural pathogens, allelopathic agents, water level/temperature, or a combination of these.

Author: R. Smith, M. Clymer, D. Dunn, S. Myers

Author Affliation: LCWC

Journal: MT MTU REPORT FINAL  Grant c 311018

Abstract:

A field trial to evaluate the ability of Mycoleptodiscus terrestris ( Mt) to control growth of non-native Eurasian watermilfoil (Myriophyllum spicatum), or EWM, was conducted in the Les Cheneaux Islands (LCI), Michigan during the summer of 2017. Objectives of the trial were to confirm effective biological control of EWM by Mt observed during a 2014 trial conducted in the Les Cheneaux area; and to learn if Mt efficacy against EWM could be reproduced when the fermentation process wasconducted in a different laboratory and at a larger scale. Findings indicate that the Mt strain, NRRL TX-05, did retain efficacy in controlling EWM growth in the Les Cheneaux open-water system during the 2017 field trial. Moreover, it was learned that Mt efficacy in controlling EWM growth continues when water temperatures are lower than optimum. The degree to which Mt infected EWM was quantified by measuring biomass reduction as a function of time. Follow-up observations one year post treatment suggest that EWM vigor might be reduced during the season following Mt treatment. Results from LCI field trials evaluating the mycoherbicidal activity of Mt for EWM management are encouraging. Based upon our studies of 1/6^th and 1/8^th acre plots as well as previous data, Mt is a strong candidate as a commercial competitor to chemical herbicides for EWM management in lakes, harbors and waterways.

Authors: R. Smith, M. Clymer, D. Dunn, S. Myers

Author Affiliation: LCWC

Journal: Unpublished LCWC Report 29 April 2018

Abstract: A field trial to evaluate the ability of Mycoleptodiscus terrestris ( Mt) to control growth of non-native Eurasian
watermilfoil (Myriophyllum spicatum), or EWM, was conducted in the Les Cheneaux Islands (LCI), Michigan during the summer of 2017. Objectives of the field trial were to confirm effective biological control of EWM by Mt observed during a 2014 trial conducted in the Les Cheneaux area; and to learn if Mt efficacy against EWM could be reproduced when the fermentation process was conducted in a different laboratory and at a larger scale. Findings indicate that the Mt strain, NRRL TX-05, did retain efficacy in controlling EWM growth in the Les Cheneaux open-water system during the 2017 field trial. Moreover, it was learned that Mt efficacy in controlling EWM growth continues when water temperatures are lower than optimum. The degree to which Mt infected EWM was quantified by measuring biomass reduction as a function of time. Results from LCI field trials evaluating the mycoherbicidal activity of Mt for EWM management are encouraging. Based upon our studies and previous data, Mt is a strong candidate as a commercial competitor to chemical herbicides for EWM management in lakes, harbors and waterways.

Authors: R. Smith

Author Affiliation: LCWC

Journal: Unpublished Report; March 2017

Abstract: Three lines of evidence suggest that characteristics of Les Cheneaux waters have changed during the past four years as reflected by a sharp decline in stemmed aquatic plants, especially Eurasian watermilfoil (EWM), and in free-floating algae (phytoplankton) densities. Eurasian watermilfoil density decreased by 80% from 2013 through 2016 in the two most infested bays, Sheppard and Cedarville, for this period. This is not to say that LCI water quality has declined. In fact, the recreational water quality of LCI waters is excellent. The shift in EWM and plankton densities appears real and, with the decline of EWM as well as the plankton community, long term shifts in the lower aquatic food web could occur. Changes in the lower food web can affect the invertebrate populations such as dragonflies, mayflies and damselflies which, in turn, can affect the fishery.

Two other lines of evidence for shifting water characteristics are the decrease in algae concentration and the simultaneous rise in Soluble Reactive Phosphorus (SRP), a primary algal nutrient during the 2013-2016 period. SRP concentration increased throughout LCI waters as the planktonic algae community density decreased. With SRP being a primary planktonic algae nutrient, it follows that SRP concentrations would increase if the algal population had less demand for using it as a nutrient.

Author: Mark Clymer

Author Affiliation: LCWC

Journal: Unpublished Report for the Mackinac County Board of Commissioners and the Clark Township Board

Abstract: This Milfoil Control Project and it’s impact are part of a functional and ecosystem level effort in the Les Cheneaux Islands (LCI) watershed to balance native and invasive species by facilitating the natural diversity still present.

Results of this project indicate that some Aquatic weeds appear able to compete with Milfoil, and that Milfoil does not appear to be as severe an ecological threat in LCI currently as was witnessed in 2011‐2013. This statement does not mean there is no problem, only that under favorable conditions the Pondweed family, Naiad, Chara, and Eel Grass for instance, are able to successfully cohabitate with Milfoil, as demonstrated in the 2014 Aquatic Vegetation Assessment Site (AVAS) survey and a Point Intercept (PI) survey findings. Favorable factors include cooler water temperatures, less available sunlight, and the presence of Milfoil pathogens & predators.

Author: Bridget Faust

Author Affiliation: Association of State Floodplain Managers

Journal: Great Lakes Coastal Resilience Planning Guide; February 14, 2014

Abstract: Demonstrate how low water levels and invasive species have adversely impacted the Les Cheneaux Watershed, describe the different strategies used by the community to combat them, and provide communities with the decision support tools necessary to decide when and how to manage invasive species.

Author: Mark Clymer

Author Affiliation: LCWC

Journal: EPA/GLRI Invasive Species Grant: No. GL-00E00809; March 31, 2014

Abstract:  This project supports the Great Lakes Restoration Initiative and the Great Lakes Water Quality Agreement, pursuant to Public Law 112-10. The grant will support the Les Cheneaux Watershed Council’s work to stock 65,000 milfoil weevils in approximately 16 locations in three bays in the Les Cheneaux Islands region of northern Lake Huron, Michigan to control the invasive Eurasian watermilfoil and restore important perch spawning grounds. The project includes monitoring to assess the long-term effectiveness of this biological control strategy for watermilfoil.