Skaneateles Conservation Area/Invasive species/Dipsacus

<< Prohibited invasive plants at the SCA

Dipsacus spp. (teasels)

Teasels (Dipsacus species) are common in the old fields and some more wooded parts of the Skaneateles Conservation Area (SCA).

• Wild teasel, Dipsacus fullonum (≡ D. sylvestris ≡ D. fullonum ssp. sylvestris) is the most likely teasel to be found at the SCA.
• Cutleaf teasel, Dipsacus laciniatus is less likely to be found at the SCA, but it is present in nearby towns Elbridge and Marcellus.
• Fuller's teasel, Dipsacus sativus was probably cultivated in the area, but not known to naturalize, so probably unlikely at the SCA.

Invasiveness ranking for Dipsacus spp. (teasels)

The 2009 New York State invasiveness ranking assessed Dipsacus laciniatus explicitly and did not assess Dipsacus fullonum at all. However, subsequent listings from individual New York PRISMS have ranked Dipsacus fullonum as highly invasive.

• Dipsacus laciniatus (cut-leaf teasel) is listed as highly invasive with a relative maximum score of 68/90 = 75.56% and is prohibited by New York State law.
• Dipsacus fullonum (wild teasel) is listed as highly invasive but not regulated by state law.
• Dipsacus sativus (fuller’s teasel) was formerly cultivated in this area but not known to naturalize.

Dipsacus laciniatus and Dipsacus fullonum are similar in appearance and are known to hybridize. The primary difference is deeply-lobed leaves of D. laciniatus.

1. Ecological impact (20/30)

1.1. Unknown impact on ecosystem processes and system-wide parameters (U)

• Dipsacus laciniatus has been known in the U.S. since the 1800s, but specific studies on its impacts to ecosystem processes and system wide parameters are not known

1.2. Significant impact in at least one layer (7/10)

• Large stands can significantly increase the density of the herb layer, and also significantly increasing the height of the herb layer up to 3 m.

• Teasels significantly alter the structure of rare natural plant communities.

1.3. Major alteration in community composition (10/10)

1.4. Minor impact on other species or species groups (3/10)

2. Biological characteristics and dispersal ability (16/25)

2.1. Abundant reproduction (4/4)

• Large plants can produce over 2000 seeds.
• Viability is high, often ≥ 80%
• Teasel seed bank is short lived. Less than 1% of Fuller's teasel emerged after 5 years of storage in the soil

2.2. Infrequent or inefficient long-distance dispersal (1/4)

• Most seeds fall near the parent plant.

• Teasel seeds are not morphologically adapted for wind dispersal. Most fall within 5 ft. of plant.

• Occasional long distance dispersal by water and wind, possibly assisted by highways that create wind corridors, may occur despite specific adaptations

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

• Readily dispersed by mowing equipment

• Occasionally sold for cultivation and in dried flower displays (now prohibited in NY but still picked for this purpose)

• Roadsides, fields, and waste places. It does very well along some of the major interstates and is clearly spreading and becoming more common.

• Dispersal along roads and waterways has been important to teasel spread in North America.

2.4. Possesses one characteristic that increase competitive advantage (3/6)

• Perennial or biennial monocarp (i.e., dies after setting seed)

2.5. Forms a dense layer above shorter vegetation and forms dense thickets (2/2)

• Forms a very dense tall thickety layer above shorter vegetation

2.6. Can germinate/regenerate in existing vegetation in a wide range of conditions (3/3)

2.7. Other species in the genus are not invasive in New York or elsewhere (0/3)

• Dipsacus fullonum, D. sativum, D. sylvestris not tracked as invasive here or elsewhere.
• D. laciniatus is not as common as the common teasel (D. sylvestris)
• Currently (2021), a number of state and federal agencies do appear to consider Dipsacus fullonum to be invasive at some level.

3. Ecological amplitude and distribution

3.1. Large dense stands present in areas with few other invasive species present (4/4):

• Large stands can occur over 0.25 acres sometimes in areas lacking other invasives.

3.2. Known to occur in four or more natural habitats (6/6):

• Wetland: Freshwater marshes, Peatlands, Shrub swamps
• Upland: Grasslands/old fields, Forests/woodlands

3.3. Can establish independent of any known natural or anthropogenic disturbances (4.4):

• Although found in disturbed areas, also reported in undisturbed areas such as limestone fens, meadows and stream corridors.

3.4. Native range includes climates similar to those in New York (3/3)

• Native to temperate Europe and Asia.

3.5. Present as a non-native in >8 northeastern USA states and/or eastern Canadian provinces (4/4):

• Present in KY, IN, IL, IA, MA, MD, MI, MN, MO, NJ, NY, OH, PA, VA, WI, WV, ON, QC.

Observations of Dipsacus spp. (teasels) at the SCA

The following photographs and corresponding iNaturalist observations of Dipsacus were made at or very near the Skaneateles Conservation Area. Click on images to enlarge and read details on Wikimedia Commons or on the "iNat obs" links to view the corresponding observations at iNaturalist.

• Dipsacus fullonum west of the landfill at the SCA, 3 May 2012. iNat obs
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• Dipsacus fullonum in the Phrag around the lower beaver pond, 31 Oct 2015. iNat obs
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