A NextGen Blog by Paige Aldenberg, University of Vermont.
This is the latest NWNL NEXTGEN BLOG post. Since 2007, NWNL has fostered watershed education with internships and blog opportunities. Our NWNL NEXTGEN BLOG series hosts student essays; sponsors a forum for its high school senior, college and grad contributors; and invites proposals from new students to write on watershed values, threats and solutions.
Paige Aldenberg is an undergraduate student at the University of Vermont, majoring in Environmental Science with minors in German and Geospatial Technologies. Her interest in No Water No Life started after writing for her university’s environmental publication. She is currently focusing on water quality research and environmental justice. Read her earlier NWNL Blog post Lost Footprints in the Sand.
Nestled between Canada, New York and Vermont is Lake Champlain – home to the Abenaki and Mohawk Tribes. Stripped of its title as a “Great Lake” in 1998 – a title that only lasted for 18 days – this lake remains critical through its rich history and the ecosystem services it provides.
With over 90 fish species and 318 bird species, Lake Champlain has become a center for recreation and environmental research. However, dangerous invasive species are currently putting the lake’s health at risk.[mfn]Lake Champlain Land Trust[/mfn] There are 50 known, non-native species in Lake Champlain. These species were introduced after European colonization, and now over a dozen are considered invasive and harming the economic, environment and human health.
Aquatic Invasive Species (AIS) impact the lake’s health and food chain. AIS also result in an increase of toxic algae blooms and a decline of native species. Human activity is the main cause for AIS spread, but there are many programs to mitigate AIS infestations.[mfn]Lake Champlain Basin Program[/mfn] This blog further explores some of Lake Champlain’s biggest AIS threats and key mitigation management tools, also applicable to other freshwater ecosystems facing similar threats.
Zebra Mussels (Dreissena polymorpha)
After being first introduced to the Great Lakes in 1988 from ballast water and cargo ships, zebra mussels started to make Lake Champlain their home. They continue today to reproduce in mass numbers and create competition for space and food with native species.
Zebra mussels are filter feeders, meaning they consume phytoplankton and quickly clear the water around them. This reduces the food sources that native species rely on and increases water clarity, which helps other predators to hunt native species. This competition for food causes extreme shifts in the food web. Zebra mussels also attach themselves to native mussels and make them unable to function and regulate water, leading to their suffocation.[mfn]National Park Service[/mfn] Zebra mussels have also been linked to toxic green-blue algae blooms found in Lake Champlain and the Great Lakes.[mfn]Lake Champlain Basin Program[/mfn]
Water Chestnut (Trapa natans)
The water chestnut is native to western Europe, Africa and Eastern Asia. First noted in Cambridge Botanical Garden at Harvard University, this “ornamental” plant was introduced to North America in the 1870’s for ponds.[mfn]New York Invasive Species Information[/mfn] It quickly spread across the northeastern United States and reached Lake Champlain by the 1940’s.
This species forms mats that prevent native plants from growing and lowers the oxygen levels that native fish and organisms need to survive. These dense mats also limit recreational activities and boat traffic. The water chestnut drops spiny seeds that have potential for growth for up to 12 years, which made them extremely difficult to manage.[mfn]Lake Champlain Basin Atlas[/mfn]
Spiny Water Flea (Bythotrephes longimanus)
Spiny water flea was most recently added to the AIS list in 2014. The spiny water flea was first introduced to the Great Lakes through ballast water in the 1980’s, but has since spread to Lake Champlain.
This small crustacean, native to Northern Europe and Asia, feeds on other zooplankton. The native species in the lake are now in direct competition for these food sources. Predictions state that this competition will lead to a population drop of the native competitors (ie., rainbow smelt and filter-feeding mysids which are water-quality indicators), as well as cause a decline of the prey of these species. One value of the lake’s native species is that they keep nutrient and energy levels in check. Thus,, when their populations decrease, the lake’s health becomes unbalanced, resulting in increased algae blooms and mercury levels.[mfn]Lake Champlain Committee[/mfn]
The native species will continue to be outcompeted due to positive impacts of today’s warming climate on invasive species. For instance, invasive spiny water fleas are expanding their territory as temperatures rise. Simultaneously, higher water temperatures will negatively impact the spawning of native cold-water, native fish species, thus impacting recreational fishing on the lake.[mfn]Lake Champlain Basin Program[/mfn]
Mitigation in Your Local Lake
Researching how these species thrive and their ecological impact is a great first step in controlling AIS spread. Although difficult to manage, mitigating invasive species is rewarding for the health of the ecosystem and community![mfn]Eat the Invaders[/mfn]
For some vegetative or mussel species, the best method for mitigation is mechanical harvesting or hand-pulling invasive plants from the water body. Local environmental organizations offer volunteers opportunities to remove or relocate these species to prevent clogged pipes and crowded surfaces.
Other invasive that cannot be physically removed are reduced by applying the CLEAN, DRAIN, DRY mantra for boaters. This ensures that all recreational equipment entering the lake is cleaned of visible organisms; drained of all lake water; and dried to kill any remaining organisms still alive in any excess water.
These mitigation techniques will not entirely solve the harmful impacts that AIS have on our freshwater bodies. That being said, much progress has been made for safe-guarding water and human health through these community-driven initiatives. If we continue to share these tools as approaches for other lake communities at risk, AIS issues will progress with time.
“Aquatic Invasive Species.” Lake Champlain Basin Program. 2018 State of the Lake and Ecosystem Indicators Report, June 2018. Accessed Dec 2, 2020, by PA. https://sol.lcbp.org/en/healthy-ecosystems/aquatic-invasive-species/
“Climate Change Impacts.” Lake Champlain Basin Program, 2020. Accessed Dec 7, 2020, by PA. https://www.lcbp.org/water-environment/climate-change/climate-change-impacts/
“Cyanobacteria.” Lake Champlain Basin Program, 2020. Accessed Dec 7, 2020, by PA. https://www.lcbp.org/water-environment/human-health/cyanobacteria/
“Home.” Eat the Invaders, 2020. Accessed Dec 3, 2020, by PA. http://eattheinvaders.org/
“Invasive Zebra Mussels.” National Park Service, Aug 1, 2017. Accessed Dec 2, 2020, by PA. https://www.nps.gov/articles/zebra-mussels.htm
“Lake Champlain Facts.” Lake Champlain Land Trust, 2020. Accessed Dec 2, 2020, by PA. https://www.lclt.org/about-lake-champlain/lake-champlain-facts/
“Spiny Water Flea Have Arrived- What Next?” Lake Champlain Committee, Sept 2014. Accessed Dec 2, 2020, by PA. https://www.lakechamplaincommittee.org/learn/lake-look/spiny-water-flea-have-arrived-what-next/
“Water Chestnut.” Lake Champlain Basin Atlas, 2020. Accessed Dec 3, 2020, by PA. https://atlas.lcbp.org/issues-in-the-basin/aquatic-invasive-species/water-chestnut/
“Water Chestnut.” New York Invasive Species Information, Sept 25, 2019. Accessed Dec 3, 2020, by PA. http://nyis.info/invasive_species/water-chestnut/