Skaneateles Conservation Area/Invasive species/Phalaris arundinacea



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Phalaris arundinacea (reed canarygrass)
Although floras have traditionally treated reed canary grass (Phalaris arundinacea) as a single circumboreal (thus native) species, it now seems to be fairly-well accepted that most, if not all, reed canary grass in New York State is, to some degree, of a nonnative genotype that turns out to be highly invasive here.

Identification
Reed canary grass is one of the first grasses to sprout in the spring. Dense green-to-purple flower clusters appear in May to mid-June and gradually change to a yellowish brown color. Mature height ranges from about 3 to 9 feet.

Invasiveness ranking for Phalaris arundinacea (reed canarygrass)
The New York State invasiveness ranking for reed canarygrass (Phalaris arundinacea) is high (77.78%).

Phalaris arundinacea is not regulated by New York State law. and has no federal designation within the United States or Canada. Its economic importance for agricultural use contributes to its unregulated status.

1. Ecological impact (20/30)
1.1. Impact on Natural Ecosystem Processes and System-Wide Parameters: Influences ecosystem processes to a minor degree (3/10):


 * Reed canarygrass promotes silt deposition and consequent constriction of waterways.

1.2. Impact on Natural Community Structure: Significant impact in at least one layer (7/10)


 * Can form dense, persistent, monotypic stands of creeping rhizomes in a thick sod layer (over 0.5 meters thick)


 * Can facilitate Phragmites infestation within the context of hydrologic disturbance. In these dense infestations it can eliminate layers below.

1.3. Impact on Natural Community Composition: Major alteration in community composition (10/10)


 * Can form dense, persistent, monotypic stands that exclude and displace native plant species.


 * In NYS there are many occurrences of freshwater wetlands dominated by P. arundinacea with major impacts to on biodiversity, and likely associated increases in other exotic species.

1.4. Impact on other species or species groups: Unknown impact on other species or species groups (0/0)


 * Monotypic stands would probably alter native animal foraging habits.


 * The displacement of woody vegetation by reed canarygrass may reduce the number of arthropods foraging in riparian areas

2. Biological characteristics and dispersal ability (21/25)
2.1. Mode and rate of reproduction: Abundant reproduction (4/4)


 * Various studies state seed produced, but not quantified


 * Abundant vegetative spread by creeping rhizomes

2.2 Innate potential for long-distance dispersal: Numerous opportunities for long-distance dispersal (4/4)


 * Seed dispersal is passive by water (hydrochory) and does form a soil seed bank


 * Seeds not adaptated for long-distance dispersal, but both rhizome fragments and seeds are dispersed via flowing water.

2.3. Potential to be spread by human activities: High (3/3)


 * Long agronomic history in the U.S. with forage cultivation occurring as early as the 1830s.


 * Extensively cultivated for use as hay and for forage for livestock.


 * Used for erosion control and revegetation of disturbed sites (e.g. pipeline corridors).


 * Used to mitigate nitrate pollution, road construction, ornamental plantings.


 * Indirectly spread through yard waste disposal and soil movement.

2.4. Characteristics that increase competitive advantage: Two or more characteristics that increase competitive advantage (6/6)


 * Perennial with creeping rhizomes.


 * Current populations may have evolved from cultivars that were crossbred for fast growth


 * High net photosynthetic rates.


 * Has as a high tolerance for varying nutrient and oxygen levels, and can live in fluctuating and submerged water successfully.


 * Morphologic plasticity gives it advantages over other species.


 * Different above- and below-ground biomass production (growth) strategies are probably common within populations of reed canary grass and may be important for it to successfully invade new habitats.


 * Another study (Herr-Turoff & Zedler, 2007) found Phalaris grew as a sward with intermittent and early-season flooding but shifted to tussocks under constant flooding.


 * Additional plasticity regarding histological differences between the folded and flat leaves may give Phalaris greater amplitude for invading dryer ecosystems.

2.5. Growth vigor: Has climbing or smothering growth habit, forms a dense layer above shorter vegetation, forms dense thickets. (2/2)


 * Reed canarygrass can form dense, persistent, monotypic stands forming a dense layer above shorter vegetation.

2.6. Germination/Regeneration: Can germinate/regenerate in vegetated areas but in a narrow range or in special conditions. (2/3)


 * Seeds germinate immediately after ripening with no known dormancy requirements.


 * Germination rates increase significantly with light availability.

2.7. Other species in the genus invasive in New York or elsewhere: No. (0/3)

3. Ecological amplitude and distribution (/)
3.1. Density of stands in natural areas in the northeastern USA and eastern Canada:

3.2. Number of habitats the species may invade:

3.3. Role of disturbance in establishment:

3.4. Climate in native range:

3.5. Current introduced distribution in the northeastern USA and eastern Canada:

3.6. Current introduced distribution of the species in natural areas in the 8 NY PRISMs:

4. Difficulty of control (/)
4.1. Seed banks:

4.2. Vegetative regeneration:

4.3. Level of effort required:

Management of Phalaris arundinacea (reed canarygrass) at the SCA
Reed canary grass (RCG) is a cool-season perennial grass that can easily invade sunny wet areas. Management options include burning, excavation, tree/shrub planting, grazing, mowing, herbicide application, mulching/solarization.

A combination treatments would probably be most effective for typical cases. An appropriate option might be to plant trees and keep the area between them mowed, tarped or mulched until the trees become large enough to shade out the RCG. Because of the rapid growth rate of RCG during the early and late parts of the growing season, several consistent mowings would be required to keep the RCG from overtopping tree seedlings and running the risk of mowing them down.