A Controversial Carnivore--
Aldrovanda vesiculosa aka Waterwheel
By Sharyn Walz
I have to admit it: I am fascinated by this plant! It’s both super-cool and pretty scary, but either way, it’s easy to understand why this could be a BIG problem here in NJ!
Waterwheel is different than any other invasive species we’ve discussed so far—it grows in the water, at an amazing rate when conditions are right, and it’s carnivorous! That’s right, this smallish plant traps its own food, very similar to a Venus Flytrap or bladderwort, Utricularia sp., which is native to NJ and has been seen as close as Assunpink Lake. Both of these carnivores have traps that are super-quick—and exhibit some of the fastest plant movement on record!
http://link.springer.com/article/10.1007/BF02806556
http://www.njisst.org/documents/2016Conference/Aldrovanda%20vesiculosa%20Friend%20or%20Foe.pdf
http://www.njisst.org/docuements/DoNotPlantList.pdf
https://en.wikipedia.org/wiki/Aldrovanda_vesiculosa
http://www.ourbreathingplanet.com/waterwheel-plant/
http://www.invasive.org/browse/subinfo.cfm?sub=77104
http://www.mdinvasivesp.org/archived_invaders/archived_invaders_2016_01.html
http://www.arkive.org/waterwheel/aldrovanda-vesiculosa/
http://wiki.bugwood.org/Aldrovanda_vesiculosa/NJ
Aldrovanda vesiculosa aka Waterwheel
By Sharyn Walz
I have to admit it: I am fascinated by this plant! It’s both super-cool and pretty scary, but either way, it’s easy to understand why this could be a BIG problem here in NJ!
Waterwheel is different than any other invasive species we’ve discussed so far—it grows in the water, at an amazing rate when conditions are right, and it’s carnivorous! That’s right, this smallish plant traps its own food, very similar to a Venus Flytrap or bladderwort, Utricularia sp., which is native to NJ and has been seen as close as Assunpink Lake. Both of these carnivores have traps that are super-quick—and exhibit some of the fastest plant movement on record!
- What does it look like? Waterwheel is rootless and floats free on the water. Stems are 2-8” long, and have “wheels” of leaves arranged in a spiral, with a bean-shaped trap on the outward end. Waterwheel prefers to live in wetlands and streams, and doesn’t do well in containers. Waterwheel survives the winter by sinking small pods called turions that float up in spring and reproduce.
- Where is it from? It is most commonly found in warm, shallow standing water, within brightly lit areas. Native to Africa, Asia, Australia, Europe, Japan, Korea and listed as "Endangered’ on the IUCN Red List of Threatened Species. Such a large distribution area, yet considered rare in its native areas now. This plant is on the brink of extinction worldwide.
- Where is it going? In North America, it is known to be introduced and locally abundant only in New Jersey, New York, and Virginia. It was brought to NJ in 1999 by a person interested in carnivorous plants, and was originally kept on an isolated private property. Now, it can be found in Sussex County and in NJ DEP’s Bear Swam Wildlife Management Area (3,000 acres forest/wetland/open water site). The introduced populations in North America rival or surpass in size the largest populations in the species' entire natural range. A single pond in New York is estimated to have a population of several million individuals!!
- So how did the waterwheel get here? It is a long and sordid story, involving the intentional planting of the species at various locations in NJ and NY, by well-intentioned individuals who hoped to provide refugial patches for the species in North America in case it went extinct in its native range. Though well-intentioned, these deliberate introductions may come back to haunt us, as this species spreads across eastern North America preying on native fauna and impacting habitats in ways we've never before seen.
- How is it spread? Aldrovanda is spread mainly through the movement of waterfowl - plants sticking to the feet of a bird are transported to the next aquatic destination on the bird's route. As a result, most Aldrovanda populations are located along avian migratory routes. Humans can transport intentionally and non-intentionally. Some spread is the result of overwintering turions, or possibly flooding caused by Hurricane Irene and Superstorm Sandy.
- Why is it a problem? Waterwheel can easily overwhelm a water body once established, causing many problems for humans and ecosystems. Growth is quite rapid (faster than bladderwort), so that in optimal conditions a whole new whorl is produced once or more each day. Traps number up to 200 per plant and researchers estimate that up to 80% of the traps may contain prey at any given time. These traps catch untold numbers of insects and other animals, giving scientists great concern about waterwheel's effect on food webs and rare invertebrate species. No documentation is available on what species waterwheel consumes in North American wetlands.
- How can it be controlled? Controlling waterwheel is a serious task, though there is little data on the topic. No control efforts have yet been successful in Virginia, where the most control work has been done. In 2014, 36 pounds of turions were collected and removed from a pond at Fort A.P. Hill, VA with no apparent impact to the waterwheel population in the subsequent year. Waterwheel is currently listed on the NJ Invasive Species Strike Team’s DO NOT PLANT list as a Watch Species. Waterwheel is eaten by tadpoles, some grazing waterfowl, small fish, and snails, but its biggest enemy seems to be a fungus. Treatment options may include herbicide and hand-pulling. (Herbicide application requires permit - wetland appropriate herbicide should be applied by a professional lake manager)
- What’s so controversial? Some people are growing Waterwheel to “protect” it in case it becomes extinct in the wild. Some people think it should be cultivated as a possible mosquito control agent. Due to its unusual look and interesting carnivorous nature, some people are growing it and selling it for profit. There are many novelty items being marketed with distinctive Waterwheel designs--
http://link.springer.com/article/10.1007/BF02806556
http://www.njisst.org/documents/2016Conference/Aldrovanda%20vesiculosa%20Friend%20or%20Foe.pdf
http://www.njisst.org/docuements/DoNotPlantList.pdf
https://en.wikipedia.org/wiki/Aldrovanda_vesiculosa
http://www.ourbreathingplanet.com/waterwheel-plant/
http://www.invasive.org/browse/subinfo.cfm?sub=77104
http://www.mdinvasivesp.org/archived_invaders/archived_invaders_2016_01.html
http://www.arkive.org/waterwheel/aldrovanda-vesiculosa/
http://wiki.bugwood.org/Aldrovanda_vesiculosa/NJ