What effect are management actions
the arrival and spread of AIS?
Boat launch steward and greeter programs have helped to prevent the introduction and spread of invasive species by intercepting invasives at points of arrival and departure from water bodies. New regulations are helping to make these programs more common and effective. AIS removal efforts, such as those for water chestnut and Asian clam, have also helped to control the spread of invasives that have already arrived.
In 2007, LCBP initiated the Lake Champlain Boat Launch Steward program. This program stations stewards at public boat launches around the Lake, where they survey launch users and inspect their boats for the presence of invasive species when they are being launched or retrieved from the Lake. Stewards reduce the chance of introducing new species by intercepting them as they are about to enter a water body, and also educate the public about the threats posed by invasive species and the importance of cleaning boats and gear before launching into and when leaving the water body. The 2014 effort was the most far-reaching yet, with more than 31,000 visitors reached (Figure 20).
The Boat Launch Steward program also provides an important perspective on the Lake’s place in the movement of aquatic invasive species at regional and national scales. Survey data reveal that boats are trailered from as far away as Colorado and Texas. The top ten water bodies most recently visited are all in northeastern North America; the Hudson River is the water body most frequently visited in the two weeks prior to launching in Lake Champlain (Figure 21). The geographic range of visitors to the Basin, and the number of potential invaders from a variety of ecosystems, underscores the importance and effectiveness of steward and greeter programs.
Recent legislation and regulatory programs have helped to make AIS spread prevention a cornerstone of natural resource management in the Basin. New York now requires all boats, trailers, and gear to be cleaned and drained prior to launching at state access points. Additional rules prohibit sales, transportation, or introduction of certain species in New York. Similarly, Vermont has banned the transportation of aquatic plants on boats and trailers. In response to the 2009 discovery of Asian clams in Lake George and the widespread concern it raised, the Lake George Park Commission implemented a pilot mandatory boat wash and decontamination program on Lake George, the first of its kind in New York State and in the northeast region.
Following the discovery of Asian clam in Lake George in 2009, a group of partners quickly banded together to collaboratively develop a management strategy. The strategy has evolved to include research, monitoring, and intensive efforts to control the clams using benthic barrier mats and other eradication methods. Management has been very effective, but the detection of juvenile clams has been challenging. In the past few years, Asian clams have spread to several Lake George locations that are surveyed and managed where possible.
Lake Champlain’s water chestnut control program is a long-standing success story that remains dependent on steady funding and support from state, federal, and local partners. Water chestnut is a floating invasive plant that forms dense leafy mats. In the southern end of Lake Champlain, it limits boat traffic and recreational use, crowds out native plants, and creates oxygen-depleted zones uninhabitable for fish and other organisms. It was first documented in southern Lake Champlain in the 1940s, and was likely introduced through the Champlain Canal from a water garden escape or other population in the Hudson River.
Partners including the states of Vermont and New York, the Province of Québec, the Missisquoi National Wildlife Refuge, US Army Corps of Engineers, New York State Canal Corporation, Lake Champlain Basin Program, and The Nature Conservancy work to harvest water chestnut, mechanically and by hand, in Lake Champlain and other inland waters. These efforts continue to push back the northern extent of dense populations: from Benson in 2011 to south of the Dresden Narrows in 2014 (Figure 22). Progress also has been made in the Missisquoi National Wildlife Refuge where the water chestnut population was reduced by 96% between 2007 and 2014 by hand-pulling in shallow waters, though the Pike River population has rebounded recently.