Environmental Issues Seminar
2 Feb 2014
Greg Bugbee and Jordan Gibbons
Invasive Aquatic Plants Found In CT Lakes
Scientists Greg Bugbee and Jordan Gibbons, of the Connecticut Agricultural Experiment Station came to our class to talk about invasive aquatic plants that they are working to eradicate from the State of Connecticut. When one thinks about battling invasive plants, you might think that it would be just about impossible, but Greg and Jordan are using all of the latest technology, paired with scientific insight to make this a reality. The reason why invasive species are so bad in ponds is that they have abilities that allow them to out-compete the native plants, often leading to an imbalance in the pond, which reduces the overall quality. Mainly, these plants have no natural control, so they proliferate unchecked and before long, they have taken over a pond. Despite the damage that they do to the natural ecology of the pond, the number one complaint is that people cant swim, or do the other recreational activities that we all love to enjoy.
One thing that I loved about the presentation was that Greg and Jordan brought in plants of various types for all of the students to see. Being told how hard it is to identify a plant species, and actually finding out how hard it is are two very different things. After trying to identify a short display of plants, it became evident that this was a very strenuous task, and that Greg and Jordan really put a lot of thought into the work that they do. I really have a lot of respect for scientists like these two, who are such experts that all they have to do is take one look at a plant and be able to tell you more information about it than you could imagine.
The expertise that goes into identifying plants is crucial to the first step in eradicating the invasive species, which is just that, identifying them. Greg and Jordan would go to a pond, find all of the invasive species and map them so that they could see exactly which populations resided where in the ponds, and in what amounts. Once they were able to see what they were up against, they could more or less start to come up with a plan of attack. The maps were made in Global Information Systems, or GIS, which is basically a computer program, which takes data and spatially relates it so that we can better understand the relationships between the objects. To give you an idea of how widespread the issue is, a book that Greg and Jordan worked on called “Connecticut’s Aquatic and Wetland Invasive Plant Identification Guide” states that out of 201 lakes surveyed, over 61% of the lakes contained at least one invasive species (Citation 1).
Okay, so by now your probably wondering what they an actually do to combat these plants? There are a vast array of methods summarized below:
- Do nothing: Believe it or not, this can actually be a valid choice when all of the pros and cons are weighed against each other. The property owner may not want to invest the money in treating these, or perhaps the problem is not really so bad that any action necessarily needs to be taken.
- Harvesting: While this may not be the easiest way of removing the plants, sometimes hand removing the plants with divers is actually a viable option. Another option is to use cutting devices which sever the plant, and them scoop them up with nets.
- Benthic barriers: Benthic barriers are put down to basically smother the plants so that they can no longer go on with their functions, ultimately killing the plants. Greg noted that these barriers require a bit of maintenance and had to be taken out and put back in place annually.
- Drawdown: This method is just as it sounds, the water level is drawn down so that the plants are exposed to a new, uninhabitable environment and then die shortly afterwards. This is more common for public swimming like man-made ponds, and areas where the general wellbeing of the pond is not exactly natural to begin with.
- Dredging: Dredging is also a viable way of collecting these plants, where a layer of the fertile mulch that the plants need to survive is removed.
- Herbicides: Herbicides can also be used to effectively extinguish the plants, however controls to ensure that people do not swim or drink the water must be taken and weighed against the benefits of removing the plant using this method.
- Suction Harvesting: This is basically taking an underwater vacuum down and sucking up the plants.
- Biological Control: Some bugs such as milfoil weevils can be used to dine on the invasive species. Also, fish such as the grass carp can be used. Whatever is decided, the pond would get a specified amount of biological organisms per area of the pond. For example, grass carp grow to be 10-12” in a relatively short amount of time, so only 15 are needed per acre to have a healthy population. One thing to note is that the organisms are often sterile, so that they don’t end up inadvertently becoming a problem themselves.
Some of the plants were just would never truly be able to get completely out of the ponds, in which case often an intricate management plan would have to be set in place, utilizing one or more methods to keep the invasive species in check. One astonishing fact was that some of these plants called ‘Tubers’ can be dormant for 10 years!
It was helpful to know that we can all do our part in helping to combat these invasive species, which degrade our waterways and impede on our recreational activities in Connecticut. The main source of these plants Greg explained, was from fish tanks, animals and people. When people have fish tanks that they no longer want, they often just dump them out into a local pond, so that their fish can have a new home to live in. While the intent here is good, the fish often become invasive species themselves, and the plants that are in these tanks also can potentially become invasive species. Animals can help transport these species when they move from one water body to another, often physically carrying the species on their fur, or excreting them after having ingested them from another location. People are also to blame, the main source being from boat launches with the trailers often carrying the invasive species from one place to another. Overall, we can all help by just being mindful that our actions can have repercussions, and that something as simple as removing the weeds from our trailers can make a difference. The guest speakers advised us that if we did see any of these plants, they could be reported by contacting the CTDEEP with a positive identification and the location of the species found. Overall, underlying theme was that knowledge is the key to combating our invasive species problem in Connecticut. If we can identify the problem, become aware of what causes it, and take action using prescribed methods, then we really do have a fighting chance to preserve our waters so that they can exist for tomorrow as we know them today.
1. Connecticut’s Aquatic and Wetland Invasive Plant Identification Guide, 2nd, Greg Bugbee, Martha Barton, Jordan Gibbons, 2012, http://www.ct.gov/caes/lib/caes/invasive_aquatic_plant_program/pdf_reports/2012_field_guide_online.pdf