This recording includes three presentations given during the 2020 Michigan Inland Lakes Convention.
(0:00) Integrating genetics and herbicide studies to improve watermilfoil management outcomes. Ryan A. Thum
and Gregory M. Chorak, Montana State University; Jo Latimore, Michigan
State University; and Erick Elgin, Michigan State University Extension
Aquatic
plant stakeholders in Michigan increasingly recognize that Eurasian
watermilfoil (including hybrids with native northern watermilfoil) is
genetically diverse, and that strains can differ in their growth,
spread, impacts, and herbicide response. A practical challenge for
Eurasian watermilfoil management is developing methods that assess
genetic variation to predict how a specific watermilfoil population will
respond to a proposed control tactic (e.g., a specific herbicide)
before implementing management. In this presentation, we illustrate how
we are combining genetic survey and monitoring of invasive watermilfoil
populations with field and laboratory studies of herbicide response to
inform management. One significant finding of our genetic survey of
lakes across Michigan is that it is common for a given strain to be
found in more than one lake. Identifying lakes that share strains can
facilitate communication among stakeholders regarding management
experiences on particular strains. Further, by prioritizing strains to
target for herbicide studies, quantitative lab and field studies of
herbicide response can inform management on multiple lakes containing a
given strain. For example, we found one hybrid strain in eight lakes
across Michigan, and a laboratory fluridone assay identified this strain
as resistant to 6ppb fluridone. Therefore, lakes with a high proportion
of this strain of hybrid watermilfoil should not be targeted for
control with 6ppb fluridone. In contrast, our fluridone assay identified
several strains of watermilfoil that appear susceptible to 6ppb
fluridone, and therefore lakes dominated by these strains would likely
respond well to fluridone treatment. We will provide updated information
on genetic surveys and herbicide studies, and propose next steps for
integrating genetic information into management planning and evaluation.
(30:30) European Frog-bit (Hydrocharis morsus-ranae L.): Collaborative efforts towards an adaptive management framework. Blake Cahill, Central Michigan University
European frog-bit (Hydrocharsis morsus-ranae
L.; EFB) is an invasive free-floating macrophyte with the potential to
reduce the diversity of native plant, fish, and invertebrate
communities, alter the physiochemical properties of wetlands, and
inhibit the recreational and commercial use of wetlands and water
bodies. Since its putative initial escape from cultivation in Ontario in
1939, EFB has been documented in nine U.S. states and two Canadian
Provinces. European frog-bit was first documented in Michigan in the
Huron-Erie Corridor in 1996 and has since rapidly expanded its
distribution in Lake Erie and Lake Huron coastal wetlands. European
frog-bit is increasingly being detected in Michigan inland waters and
wetlands, including Fletcher Pond in 2013 (Alpena/Montmorency County),
Reeds Lake and Fisk lake in 2016 (Kent County), Maybury State Park in
2018 (Oakland County), and Pentwater Lake (Oceana County), Dansville
State Game Area (Ingham County), and the Grand River (Ottawa County) in
2019. Monitoring and management efforts have been hampered by
information gaps pertaining to biology and ecology, impacts, and
effective control strategies, and the lack of a centralized management
plan. In spring 2018, a group of stakeholders, including decision
makers, regional, state, and local management partners, researchers, and
outreach professionals, began meeting to identify critical information
and resource needs for EFB management and improve coordination and
collaboration among stakeholders. This has resulted in an engaged EFB
Collaborative and a collective effort to establish a state-wide
species-specific adaptive management framework for EFB management,
inclusive of statewide management goals and objectives and short- and
long-term strategies for EFB management. We will present on the current
state of knowledge on EFB biology and ecology, the achievements of the
EFB Collaborative, efforts to address critical information and resource
needs, and progress of the first iteration of the EFB adaptive
management framework.
(1:00:00) Monitoring and management of starry stonewort (Nitellopsis obtusa) in Wisconsin lakes. Michelle Nault, Wisconsin Department of Natural Resources
Starry stonewort (Nitellopsis obtusa;
SSW) was first reported in the U.S. in the 1970’s and has since been
documented in portions of the eastern Great Lakes as well as various
inland lakes throughout the Midwest. In September 2014, Wisconsin DNR
staff discovered a small established population of SSW in a southeastern
Wisconsin lake, marking the first time this non-native macroalgae had
been reported in the state. Since then, SSW has been verified in over a
dozen inland lakes in Wisconsin, as well as coastal portions of Green
Bay and northern Lake Michigan. This presentation will highlight the
statewide monitoring and management efforts which have occurred after
the initial discovery, including an evaluation of management efficacy
following the implementation of a variety of techniques (e.g., chemical
control, drawdown, hand-removal, DASH, etc.) to control this new
invader.
