{"id":4570,"date":"2015-04-09T10:45:31","date_gmt":"2015-04-09T14:45:31","guid":{"rendered":"http:\/\/ncseagrant.ncsu.edu\/coastwatch\/?page_id=4570"},"modified":"2024-08-29T16:23:24","modified_gmt":"2024-08-29T20:23:24","slug":"naturalists-notebook-evicting-an-invader-reducing-the-spread-of-hydrilla","status":"publish","type":"post","link":"https:\/\/ncseagrant.ncsu.edu\/coastwatch\/naturalists-notebook-evicting-an-invader-reducing-the-spread-of-hydrilla\/","title":{"rendered":"NATURALIST\u2019S NOTEBOOK: Evicting An Invader: Reducing the Spread of Hydrilla<\/em>"},"content":{"rendered":"\n\n\n\n\n

Nichole Riddle is a communications intern with North Carolina Sea Grant. She is a senior at North Carolina State University.<\/em><\/p>\n\n\n\n

In a world of minute-by-minute status updates, an invasive aquatic plant that\u2019s been in North Carolina for more than 30 years seems like old news. But experts caution against casual dismissal.<\/p>\n\n\n\n

\u201cWhen we think about a plant like Hydrilla<\/em> in some of our coastal systems \u2014 and what those coastal systems mean to the state of North Carolina \u2014 there could be some major, major problems and impacts,\u201d says Brett Hartis, an aquatic weed scientist who earned his doctorate at North Carolina State University.<\/p>\n\n\n\n

Last year, in an effort to understand the extent of this plant\u2019s spread, Gloria Putnam<\/a>, North Carolina Sea Grant<\/a> coastal resources and communities specialist, led a collaborative effort with help from the Chowan Edenton Environment Group<\/a>, or CEEG, and the Chowan Soil and Water Conservation District to sample the Chowan River near Edenton where Hydrilla<\/em> has moved from nearby creeks into the river channel and sound.<\/p>\n\n\n\n

Twelve volunteers from Chowan County assisted with sampling sites from Holiday Island to the N.C. 32 bridge that crosses the Albemarle Sound. While efforts focused on the Chowan County side of the river, some data were collected from Bertie County.<\/p>\n\n\n\n

After more than 60 hours surveying on the water, and many more hours training volunteers and adapting software that could work reliably in such a remote area, Putnam and the citizen scientists had collected data from 366 points. Invasive Hydrilla<\/em> was found at 77 locations, scattered along almost the entire length of the sampling area. See the maps on page 37.<\/p>\n\n\n\n

Putnam considers the surveying a success. \u201cWe didn\u2019t know how many areas of Hydrilla<\/em> we would find last year. With additional surveys, this data can aid us in determining whether Hydrilla<\/em> is spreading in the area.\u201d<\/p>\n\n\n\n

She hopes to learn a little more about how far Hydrilla<\/em> has extended its reach. This year, she plans to expand the sampling area farther up the Chowan River near the Virginia border and deeper into the Albemarle Sound.<\/p>\n\n\n\n

Edenton and Chowan County are one of the \u201cfirst coastal regions to be outspoken about Hydrilla<\/em>,\u201d says Marie English, a special projects associate with the Albemarle-Pamlico National Estuary Partnership<\/a>, which is within the North Carolina Department of Environment and Natural Resources<\/a>.<\/p>\n\n\n\n

And what they do might affect how the state treats Hydrilla<\/em> in the future. \u201cIt could set a precedent,\u201d she notes.<\/p>\n\n\n\n

FERTILE INVADER<\/h2>\n\n\n\n

Hydrilla verticillata<\/em>, sometimes called waterthyme, is considered an invasive, noxious weed at both the federal level and in North Carolina, as well as in 16 other states.<\/p>\n\n\n\n

Invasive species thrive in places that are not their native habitat. A noxious weed is one that is recognized to harm the area it is in \u2014 economically, ecologically or in some other way.<\/p>\n\n\n\n

Hydrilla<\/em> was brought to the U.S. for use in aquariums. Once it began spreading in waterways, however, problems quickly followed. Some issues, such as hindering boat access to the water or making swimming more difficult, were obvious. Other problems \u2014 such as altering water flow, and changing the population and individual sizes of fish \u2014 can take a longer time to develop.<\/p>\n\n\n\n

Hydrilla<\/em> is not easy to eradicate.<\/p>\n\n\n\n

First, people have to learn how to properly identify the plant before they can treat it. Hydrilla<\/em> has taken a foothold in our state partly because of its close resemblance to Elodea canadensis<\/em>, a native aquatic plant, and the invasive Egeria densa<\/em>.<\/p>\n\n\n\n

Another concern is how easily the fertile plant can spread. It is \u201cone of the worst of the worst,\u201d explains Hartis, who now works with the Tennessee Valley Authority.<\/p>\n\n\n\n

Hydrilla<\/em> produces seeds and tubers, which can sprout into new plants up to seven years later. It also can reproduce from fragmentation. The plant can grow in water as deep as 20 feet and, in lab experiments, in salinity as high as 18 parts per thousand \u2014 the salinity level in many of North Carolina\u2019s sounds and estuaries.<\/p>\n\n\n\n

\"boat
The plant is easily spread through boats and trailers that are not properly cleaned. Photo by Rob Emens.<\/figcaption><\/figure>\n\n\n\n

\u201cA lot of folks think that because of salt water, Hydrilla<\/em> won\u2019t be able to expand in the Albemarle, Pamlico and our estuaries,\u201d Hartis explains. \u201cThis plant can survive in those conditions.\u201d<\/p>\n\n\n\n

Treatment goes hand-in-hand with knowing how far the plant has spread and in what areas it\u2019s located. A downstream treatment won\u2019t be as effective if there\u2019s an infestation farther up the river. And getting the right concentration of herbicide can be difficult in an area where the water flows quickly.<\/p>\n\n\n\n

That\u2019s why the surveying work is so important. \u201cChowan County can use the information to help them make management decisions regarding treatment,\u201d says Putnam, who also serves on the Mid-Atlantic Panel on Aquatic Invasive Species.<\/p>\n\n\n\n

Deciding who will pay to treat Hydrilla<\/em> can be problematic, English points out. State and local governments, as well as citizens, have numerous priorities for limited funds and resources. When does Hydrilla<\/em> top that list?<\/p>\n\n\n\n

All of these challenges often come back to one key issue: awareness. Treatment won\u2019t help if people are unaware of the problem and continue transporting Hydrilla<\/em> into new areas for what they perceive to be beneficial reasons \u2014 or unwittingly do so via contaminated boats and trailers.<\/p>\n\n\n\n

Some people like the plant because it can attract waterfowl or assist with seasonal migrations. A potential problem, however, is Avian Vacuolar Myelinopathy, or AVM. It is a disease that causes lesions on the brains of birds that consume a neurotoxin-producing type of cyanobacteria that can grow on the underside of Hydrilla<\/em> leaves.<\/p>\n\n\n\n

Lesions also have been found in dead bald eagles, which acquire the neurotoxin indirectly after they consume other infected birds. This danger to bald eagles is especially relevant to North Carolina because Jordan Lake, in Chatham County, is home to one of the largest concentration of bald eagles in the eastern United States.<\/p>\n\n\n\n

Susan Wilde with the University of Georgia\u2019s School of Forestry and Natural Resources has been studying AVM and its potential connection to Hydrilla<\/em>. Her website, www.warnell.uga.edu\/people\/faculty\/dr-susan-wilde<\/a>, has several links where observers can report sick or dead bald eagles and other waterbirds, or send in samples of plants to be screened for the cyanobacteria.<\/p>\n\n\n\n

STATE STRATEGIES<\/h2>\n\n\n\n

North Carolina officials are drafting an Aquatic Nuisance Species Plan that will address Hydrilla<\/em> and other problematic species affecting our waterways.<\/p>\n\n\n\n

The plan is \u201can overview on the history of the problem, existing policies and programs, identification of freshwater and marine aquatic nuisance species and potential threats, and recommendations about management strategies and research needs,\u201d explains Judy Francis, with N.C. DENR in Asheville.<\/p>\n\n\n\n

\"postive
The recently named “Aetokthonos hydrillicola,” which hides on the underside of “Hydrilla” leaves, can cause a disease in birds. Photo by Susan Wilde.<\/figcaption><\/figure>\n\n\n\n

The plan currently is in review. It is expected to be available for public comment this spring.<\/p>\n\n\n\n

Separately, the N.C. Division of Water Resource\u2019s Aquatic Weed Control Program<\/a> within DENR also has been at work the past several years treating Hydrilla<\/em> at many locations across the state.<\/p>\n\n\n\n

Once the species has been identified in an area, specific spots are selected for treatment and must be periodically revisited. Treatment varies by location, with biological, chemical, mechanical and physical methods available.<\/p>\n\n\n\n

All methods require careful consideration and monitoring. A physical method, like lowering the water level, will effectively dry out any submerged Hydrilla<\/em>, as well as any other plant that also is in the water. A mechanical method, like a rake or some other type of tool, greatly increases the risk of spread by fragmentation.<\/p>\n\n\n\n

North Carolina primarily uses chemical and biological methods to control Hydrilla<\/em>. There are several different herbicides the state can use, with some being more suitable in certain areas. Some that are more selective of the plants they kill may work more slowly. Others may work faster, but be less selective. Location factors, such as proximity to seafood nurseries or flowing water, must be taken into consideration.<\/p>\n\n\n\n

In all cases, the herbicides must be ones approved for aquatic use.<\/p>\n\n\n\n

The timing of an aquatic herbicide application also must be planned responsibly, so as not to negatively impact the reproduction of local aquatic species.<\/p>\n\n\n\n

Use of grass carp as treatment presents its own unique challenge as the fish also are not a native species. They are primarily used to eat away Hydrilla<\/em> in enclosed water with lower salinity, such as reservoirs.<\/p>\n\n\n\n

BATTLING HYDRILLA<\/h2>\n\n\n\n

Students at John A. Holmes High School<\/a> in Edenton are doing their part to raise awareness about Hydrilla<\/em>. What started as something to do during a free period at school has turned into a project that is making a difference in their community, while allowing the students to learn some valuable skills.<\/p>\n\n\n\n

Science teacher Steve Karl participated in the survey of the Chowan River with Putnam and the CEEG last summer. The students began to get involved when Karl became aware of several grant opportunities.<\/p>\n\n\n\n

\u201cPeople sitting here would start adding suggestions, and then they\u2019d become involved,\u201d Karl explains. \u201cIt just started growing.\u201d<\/p>\n\n\n\n

About 12 students developed their research and communication skills as they wrote and submitted grant proposals. \u201cIt became an interest to them,\u201d says Colleen Karl, Steve\u2019s wife, a community volunteer and a member of the CEEG. \u201cNot just another school project.\u201d<\/p>\n\n\n\n

Having that interest paid off. The students won $2,000 from the What Kids Can Do<\/a> grant and $1,000 from NC State\u2019s Institute for Emerging Issues<\/a> Youth Innovation Grant. They plan to use the grant money to raise awareness with signs and surveys, to design a rake to clean off boat axles, and to provide composting barrels for Hydrilla<\/em>.<\/p>\n\n\n\n

The students\u2019 efforts already are paying off. They were invited to the Edenton-Chowan Board of Education meeting in March. They also will attend a local homeowner\u2019s association meeting and present at the annual meeting of the North Carolina Invasive Plant Council<\/a> in May.<\/p>\n\n\n\n

Steve Karl hopes that the success the students have had will inspire others.<\/p>\n\n\n\n

The students emphasize that prevention is better, and easier, than treatment. Cleaning off boats when leaving the water is a good start.<\/p>\n\n\n\n

\u201cDon\u2019t let it spread anymore,\u201d junior Kady Willis says. \u201cTry to actually keep it out of the water if you can.\u201d<\/p>\n\n\n\n

Senior Alyssa Herman adds, \u201cWe definitely can\u2019t do it alone. We have to have the community help us.\u201d<\/p>\n\n\n\n

For contact information and reprint requests, visit ncseagrant.ncsu.edu\/coastwatch\/contact\/<\/a>.<\/em><\/p>\n\n\n\n

– end –<\/p>\n\n\n\n

A GROWING PROBLEM<\/h2>\n\n\n\n

To help spread the word that Hydrilla<\/em> is in coastal waters, North Carolina Sea Grant, along with the Albemarle-Pamlico National Estuary Partnership, North Carolina State University\u2019s Department of Crop Science and Chowan County, developed a pair of videos to raise awareness about Hydrilla verticillata<\/em>.<\/p>\n\n\n\n

They detail the plant\u2019s history and impacts to our state. Interviews include citizens, managers and scientists.<\/p>\n\n\n\n

\u201cUse these videos in classrooms and community programs to educate students and citizens about Hydrilla<\/em>,\u201d suggests Gloria Putnam, Sea Grant coastal resources and communities specialist.<\/p>\n\n\n\n

\u201cAwareness is the key to successfully eradicating this invasive plant.\u201d<\/p>\n\n\n\n

Visit ncseagrant.ncsu.edu\/hydrilla<\/a> to view the videos, and find other Hydrilla<\/em>-related resources.<\/p>\n\n\n\n

OPPORTUNITIES AND RESOURCES<\/h2>\n\n\n\n

Get involved and fight Hydrilla verticillata<\/em>. Check with your town to see if it is seeking volunteers to help with its own Hydrilla<\/em> collection or research projects.<\/p>\n\n\n\n

Gloria Putnam, North Carolina Sea Grant coastal resources and communities specialist, is planning a volunteer-training event this summer in Edenton. Contact her at gloria_putnam@ncsu.edu<\/a> for details.<\/p>\n\n\n\n

Even if you cannot attend, you can request that Putnam add you to her mailing list so you can be notified of future events closer to you.<\/p>\n\n\n\n

Here are some resources to help you identify and eradicate Hydrilla<\/em>.<\/p>\n\n\n\n