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ou in the riverl Environment Rich Shaw Editor's note: This is the first in a series by the Orange County Commission for the Environment, a volunteer advisory board to the Board of County Commissioners. For more information see the Orange County State of the Environment 2014 report at nando.com/17s Problems caused by non- native, invasive aquatic plant species that flourish in many rivers and lakes in the south- ern United States are in- creasing. Many invasive plants were originally brought to the United States for use in household aquariums or or- namental ponds; they were then introduced to the envi- ronment when the aquar- iums were cleaned, or when flooding occurred at aquatic plant nurseries, ornamental ponds, or water gardens. In some cases, aquatic invasive plants have been intentional- ly introduced in a mistaken attempt to improve fish hab- itat. They can spread via boats, wind, aquatic birds, and through the natural movement of water. Hydrilla (Hydrilla verticil- lata) is an invasive, sub- merged aquatic weed that is native to Asia. It reproduces and spreads through a varie- ty of methods including the rooting of vegetative frag- ments, tubers (formed at the end of root masses), winter buds, and seeds. Tubers can remain viable for seven years or longer. It is illegal to trans- port, grow, or sell hydrilla in North Carolina. A 2 2 Invasive aquatic plants in Orange County include hy- drilla, parrot feather, creep- ing water primrose, brittle naiad, and alligator weed. The presence of hydrilla in the Eno River is the first doc- umented occurrence of this invasive plant in a free-flow- ing river system within North Carolina. The Eno is considered one of the most important rivers in the state, with at least 16 special-status aquatic plant and animal spe- cies. Many of those species are now threatened. Hydrilla was first noted in the Eno River State Park in 2005. Since then, it has spread so dramatically that park staff considers it the main management problem in the park. Hydrilla can im- pair fish communities, out- compete native aquatic vege- tation, and impede swim- ming, boating and fishing. Hydrilla has also been linked to Avian Vacuolar Myelino- pathy, a syndrome that is fa- tal for waterfowl, including birds of prey such as bald ea- gles that feed on AVM-affect- ed waterfowl. Hydrilla was detected in the West Fork Eno Reservoir in 2008 and even earlier in Lake Orange along the East Fork Eno River. Repeated management efforts have been undertaken to control this plant. The Orange Ala- mance Water System has found both hydrilla and par- rot feather in Corporation Lake, and has also taken steps to control the spread of these plants. The Orange Wa- ter and Sewer Authorityhas detected alligator weed and brittle naiad in Cane Creek Reservoir, as well as creeping water primrose in University Lalke. Rich Shaw is Orange County's land conservation manager.