Paul Smith's College NYS Department of Environmental Conservation Adirondack Park Agency Adirondack Nature Conservancy

 

Ecology

The Adirondacks have been geographically isolated for a long period of time. They are higher, further north, colder and more coniferous than the rest of the state. They also have fewer transportation and communication corridors. Unlike the rest of New York and the Northeast, until recently, the central portion of the Adirondacks has been spared incursion by invasive species. However, purple loosestrife, Japanese knotweed, common reed, garlic mustard and others have begun to follow the road corridors into the core of the Park. In the early 1990's it was rare to see any of these species in the central Adirondacks . Now there are thriving populations throughout the Park that are quietly expanding and displacing native vegetation.

Decades of research indicate that in the absence of natural predators, diseases and/or parasites, invasive species negatively impact the ecological balance of flora and fauna by out-competing native plants for light, nutrients, and space. In some cases invasive species, such as Japanese knotweed, form dense monospecific canopies shading out native species. Dense growth of plants such as purple loosestrife and common reed can alter hydrological processes leading to changes in drainage patterns, soil water holding capacity and resistance to erosive forces.

All plants reproduce through seed or vegetative means such as fragments of leaf, stem or root. Of the four species of concern, two (purple loosestrife and garlic mustard) are primarily seed reproducers and two (Japanese knotweed and common reed) reproduce primarily through vegetative propagules. The latter also produce viable seed, but generally in low quantity. All of these species have been planted as garden ornamentals. They have spread from cultivation or through improper waste disposal to roadsides and riparian areas.

Distribution in the Adirondack Park

Virtually all habitats within the Adirondack Park are susceptible to invasion and negative impact from terrestrial invasive plant species. Japanese knotweed and garlic mustard can move into more shaded areas opening the possibility for colonization of the Park's backcountry wilderness. Purple loosestrife and common reed are aggressive invaders of open wetlands. Though species such as cypress spurge (Euphorbia cyparissias) and white sweet clover (Melilotus alba) are widespread along Adirondack roadsides, they are intolerant of shade and have not shown the propensity to move off the highway ROW.

The number of species and population numbers differ between the Border and Core Conservation Areas (BCA and CCA, shown to the right). The BCA (white) has had a long history of human activity including residential dwelling and agricultural efforts and has been more heavily disturbed. There are more people, roads, buildings and agricultural fields in the BCA and established invasive plant species population centers are closer, therefore invasive species populations are also greater in the BCA.

Japanese knotweed is an herbaceous perennial which forms dense clumps 1-3 meters (3-10 feet) high. Its broad leaves are somewhat triangular and pointed at the tip. Clusters of tiny greenish-white flowers are borne in leaf axils during August and September. The fruit is a small, brown triangular achene . Knotweed reproduces via seed and by vegetative growth through stout, aggressive rhizomes. It spreads rapidly to form dense thickets that can alter natural ecosystems. Japanese knotweed can tolerate a variety of adverse conditions including full shade, high temperatures, high salinity, and drought. It is found near water sources, in low-lying areas, waste places, and utility rights of way. It poses a significant threat to riparian areas, where it can survive severe floods. It is widespread in the lower Lake George watershed along roadsides and streams. It is locally abundant in many hamlets in the Park including Indian Lake, Blue Mountain lake, Long Lake, Tupper Lake, Saranac Lake, Cranberry Lake, Warrensburg and Pottersville .

Purple loosestrife is a wetland perennial native to Eurasia that forms large, monotypic stands throughout the temperate regions of the U.S. and Canada . It has a vigorous rootstock that serves as a storage organ, providing resources for growth in spring and regrowth if the plant has been damaged from cuttings. New stems emerge from the perennial roots enabling the plant to establish dense stands within a few years. Seedling densities can approach 10,000-20,000 plants/m2 with growth rates exceeding 1 cm/day. A single, mature plant can produce more than 2.5 million seeds annually which can remain viable after 20 months of submergence in water. In addition, plant fragments produced by animals and mechanical clipping can contribute to the spread of purple loosestrife through rivers and lakes. It has limited distribution in the Park appearing mainly in roadside ditches so far. Recently it has spread throughout the Saranac River riparian zone from Saranac Lake to the Parks boundary. It is widespread in the Border Conservation Area.

Common reed grass (Phragmites) is a perennial grass that can grow to 14 feet in height. Flowering and seed set occur between July and September, resulting in a large feathery inflorescence, purple-hued turning to tan. Phragmites is capable of vigorous vegetative reproduction and often forms dense, virtually monospecific stands. It is unclear what proportion of the many seeds that Phragmites produces are viable. There is also a growing concern that the native race of phragmites (Phragmites australis var. berlandieri) is found in the Park. This is a non-invasive plant and is easy to confuse with the more aggressive Eurasian race. In either case populations are small and scattered.

Garlic mustard is a naturalized European biennial herb that typically invades partially shaded forested and roadside areas. It is capable of dominating the ground layer and excluding other herbaceous species. Its seeds germinate in early spring and it develops into a basal rosette during the first year. Garlic mustard produces white flowers between late April and June of the following spring. Plants die after producing seeds, which typically mature and disperse in August. Normally its seeds are dormant for 20 months and germinate the second spring after being formed. Seeds remain viable for up to 5 years. This plant seems to typically spread from soil that has been contaminated by its seeds. It has high local population numbers but is scattered and most prevalent in the Fulton Chain of lakes and around Elizabethtown . Anecdotal reports indicate high populations in the Lake Champlain valley.

Across the Park, these species are beginning to express dominance over native species locally and have a high potential to spread.

You can assist efforts to raise awareness about invasive species, prevent and control their spread, and track their distribution by volunteering with APIPP.

 

Prevent the Spread of Terrestrial Invasive Plants – You Can Make a Difference

  • Remove all plants fragments or propagules from clothing and vehicles such as cars, campers, trailers, ATVs, motorcycles, etc. prior to embarking on or returning from an out of town trip. This includes scraping or washing encrusted mud from the undersurface of boots or vehicles.
  • Dispose of invasive plants in a sealed trash bag, in an approved landfill, or at a transfer station.
  • Learn to identify and report invasive plants.
  • Avoid driving, running, pedaling, or walking through invasive plant infestations. This can promote their spread by picking up plant fragments or seeds on your clothing or equipment and transporting to other locations.
  • Plant native plants when landscaping. Check out this website for a preliminary list of native species in the Park: www.apa.state.ny.us/Research/ADK_Native_Plant_List.htm or check out this list of alternative native plants to invasive ornamental plants.  Another reference for native species is the New York State Flora Atlas.
  • Volunteer to assist with inventory or control activities.

What to Do if You Spot a Terrestrial Invasive Plant on Your Property

  • Confirm identification. If you need assistance in identification, collect a sample of the entire plant, including stems, leaves, and flowers, if present, and press in newspaper. Contact the APIPP Program Coordinator.
  • Review the best management practices listed on this website.
  • Determine whether you need a permit to perform controls, and obtain permit if necessary.
  • Perform the control and dispose of plants in a sealed trash bag, in an approved landfill, or at a transfer station.
  • Monitor for re-growth and repeat controls as necessary.

 

What to Do if You Spot a Terrestrial Invasive Plant along a Roadside or on Public Land

  • Record species and location (use Rt number; road reference markers if present or distance from nearest intersection; north, south, east, west directionals , etc.)
  • Review the plant distribution maps on this website to verify whether or not the infestation is recorded.
  • Report new sighting to APIPP Program Coordinator.

 Contact or Mail plant sample to:

 Hilary Oles , Program Coordinator

Adirondack Park Invasive Plant Program

c/o Adirondack Nature Conservancy

Keene Valley , New York 12943

     518-576-2082 x 131