The latest regional invasive species news chronicled the detection of a new population of didymo, also known as "rocksnot." Now in five rivers in New York, the closest of which is Kayaderosseras Creek with headwaters that lie in the southern Adirondacks, didymo is literally one step away from invading renowned trout streams such as the AuSable. A single-celled alga that blankets riverbeds, didymo is easily spread on the felt soles of waders.
Driving on state Route 73, I saw a parked car with Connecticut plates and a nearby angler on the shoreline of Lower Cascade Lake. I thought to myself, "Had he recently been in the Connecticut River, also known to be infested with didymo? Had he cleaned his waders and gear before arriving in the Adirondacks, or brought a separate pair for use here?" This is a glimpse into the thoughts of an invasion ecologist traveling the park at this time of year. 'Tis the season for invasive species.
Summer is when we often become aware of infestations - a dense bed of milfoil in a lake, a large patch of Japanese knotweed along the roadside, or a thinning crown of a tree infected with a harmful forest pest. Some municipalities, resident groups, and other organizations make calls to action to stop the spread of invasive species. These calls are getting louder, but there are still disbelievers who think that invasives are not really a problem, or that there is not anything we can do about them.
Myth: Invasive species movement is natural.
Plants and animals have moved around the globe for millennia but that movement occurred over thousands of years, not overnight. And, it largely occurred unassisted by any human intervention. Invasive species became an increasing problem in the mid 1900s.
Why? Because the increased movement of people and goods accelerated the number and rate of accidental or intentional introductions. Lands and waters can't keep up with the infusion of all of these new species, which tips the scale in favor of the invader. The resilience of forests, for example, often enabled them to weather the storm of past forest pests, but never before have they been bombarded by so many in so short of time: beech bark disease, sirex woodwasp, hemlock wooly adelgid, emerald ash borer, Asian longhorned beetle, and the list goes on.
Myth: Invasive species increase diversity.
Take for instance a wetland invaded by purple loosestrife. When loosestrife first arrives, yes, one species has been added to the existing plant community, initially. But, over time, that one species continues to spread and pushes out many other native plants by overcrowding and outcompeting them for space, nutrients, and light. Similarly, invasive animals prey upon native organisms that can result in local species extinctions.
Next to outright habitat loss, invasive species are the second leading cause of the loss of diversity outranking impacts of pollution, overpopulation, and overharvesting.
Myth: The cost of prevention and management isn't worth it.
Prevention and management do have a price, but the cost of doing nothing far exceeds an investment in action. Once invasive species are left to spread, their impacts are often irreversible. It is not just natural areas that are at risk. Invaders attacking fruit and vegetables can inflict losses on the billion dollar economy of New York agriculture by reducing crop production, increasing food prices faced by consumers, and undermining export potential.
Myth: There is nothing we can do about invasive species.
Certain invasive species are well established in some areas, but that doesn't mean that we should leave the door wide open for others to freely enter.
Opportunities exist every day to reduce their spread. Simple steps include: make cleaning recreational gear and equipment after every use part of your routine; use firewood local to the area you are visiting; landscape with non-invasive plants in the garden and alert nurseries to invasives they are selling. Education is a major part of the solution.
The Adirondack region is one of the least invaded landscapes at this scale in the country. Communities like Inlet, Tupper Lake, Lake Placid, and Lake Pleasant, among others, are demonstrating that we can do something about invasive species. We can't afford not to.
Eye on Invasives is a biweekly column that spotlights a top invader when it is easiest to identify. Hilary Smith directs the Adirondack Park Invasive Plant Program, a partnership program housed at the Adirondack Chapter of The Nature Conservancy in Keene Valley. Find out more about this award-winning program online at