Apera interrupta - (L.) Beauv.
Dense Silky Bentgrass
Other English Common Names: Italian sandgrass
Taxonomic Status: Accepted
Related ITIS Name(s): Apera interrupta (L.) P. Beauv. (TSN 41398)
Unique Identifier: ELEMENT_GLOBAL.2.140037
Element Code: PMPOA0G010
Informal Taxonomy: Plants, Vascular - Flowering Plants - Grass Family
 
Kingdom Phylum Class Order Family Genus
Plantae Anthophyta Monocotyledoneae Cyperales Poaceae Apera
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Concept Reference
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Concept Reference: Kartesz, J.T. 1994. A synonymized checklist of the vascular flora of the United States, Canada, and Greenland. 2nd edition. 2 vols. Timber Press, Portland, OR.
Concept Reference Code: B94KAR01HQUS
Name Used in Concept Reference: Apera interrupta
Conservation Status
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NatureServe Status

Global Status: GNR
Global Status Last Changed: 22Mar1994
Rounded Global Status: GNR - Not Yet Ranked
Nation: United States
National Status: NNA
Nation: Canada
National Status: NNA (10Oct2016)

U.S. & Canada State/Province Status
United States Arizona (SNA), California (SNA), Colorado (SNA), Hawaii (SNA), Idaho (SNA), Indiana (SNA), Massachusetts (SNR), Michigan (SNA), Missouri (SNA), Montana (SNA), Nevada (SNA), New Jersey (SNA), New Mexico (SNA), New York (SNA), Ohio (SNA), Oregon (SNA), Utah (SNA), Washington (SNA), Wisconsin (SNA), Wyoming (SNA)
Canada British Columbia (SNA), Ontario (SNA)

Other Statuses

NatureServe Global Conservation Status Factors

Other NatureServe Conservation Status Information

Distribution
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U.S. States and Canadian Provinces
Color legend for Distribution Map
NOTE: The distribution shown may be incomplete, particularly for some rapidly spreading exotic species.

U.S. & Canada State/Province Distribution
United States AZexotic, CAexotic, COexotic, HIexotic, IDexotic, INexotic, MA, MIexotic, MOexotic, MTexotic, NJexotic, NMexotic, NVexotic, NYexotic, OHexotic, ORexotic, UTexotic, WAexotic, WIexotic, WYexotic
Canada BCexotic, ONexotic

Range Map
No map available.

Ecology & Life History Not yet assessed
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Economic Attributes Not yet assessed
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Management Summary Not yet assessed
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Population/Occurrence Delineation Not yet assessed
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Population/Occurrence Viability
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U.S. Invasive Species Impact Rank (I-Rank)
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Disclaimer: While I-Rank information is available over NatureServe Explorer, NatureServe is not actively developing or maintaining these data. Species with I-RANKs do not represent a random sample of species exotic in the United States; available assessments may be biased toward those species with higher-than-average impact.

I-Rank: Medium/Insignificant
Rounded I-Rank: Unknown
I-Rank Reasons Summary: Apera interrupta is a non-native grass species that in some cases has entered the United States via contaminated grass seed. It is widespread in the western states, in a few states in the midwest and in a few states in the east. This is most invasive in Oregon and Washington and noted there to have the potential to spread further. It tends to occur in disturbed places and doesn't appear to have a lot of reproductive characters that make it highly aggressive.
Subrank I - Ecological Impact: Medium/Insignificant
Subrank II - Current Distribution/Abundance: Medium/Low
Subrank III - Trend in Distribution/Abundance: Medium/Insignificant
Subrank IV - Management Difficulty: Unknown
I-Rank Review Date: 17May2004
Evaluator: Oliver, L.
Native anywhere in the U.S?
Native Range: This grass species is native to Asia and Europe (GRIN).

Download "An Invasive Species Assessment Protocol: Evaluating Non-Native Plants for their Impact on Biodiversity". (PDF, 1.03MB)
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Screening Questions

S-1. Established outside cultivation as a non-native? YES
Comments: Apera interrupta is established as a non-native in much of the western United States, in a few midwestern states and a few states in the east (Kartesz 1999).

S-2. Present in conservation areas or other native species habitat? Yes
Comments: While this species appears to mainly occur in disturbed habitats, it has been reported in New York in native species habitats including saline flats, rocky flats and moist stream banks (NYFA Newsletter 1992). In Utah, this species has been recorded in greasewood communities (Welsh et al. 1993). This species mainly appears to be a lawn weed (NYFA Newsletter 1992, Welsh et al. 1993).

Subrank I - Ecological Impact: Medium/Insignificant

1. Impact on Ecosystem Processes and System-wide Parameters:Low significance/Insignificant
Comments: No information was found about how this species impacts abiotic and system wide parameters of the ecosystems where it occurs.

2. Impact on Ecological Community Structure:Low significance
Comments: Apera interrupta is a grass species (Weber and Whitman 1996) and only affects one vegetative layer.

3. Impact on Ecological Community Composition:Unknown

4. Impact on Individual Native Plant or Animal Species:Unknown

5. Conservation Significance of the Communities and Native Species Threatened:Unknown

Subrank II. Current Distribution and Abundance: Medium/Low

6. Current Range Size in Nation:High significance
Comments: Apera interrupta is known from nearly every state in the west, a few states in the midwest and a few states in the east (Kartesz 1999).

7. Proportion of Current Range Where the Species is Negatively Impacting Biodiversity:Low significance/Insignificant
Comments: This grass species has been reported as 'most invasive- regional' in Oregon and Washington (WNPS Exotic Pest Plants of Greatest Concern). 'Most invasive-regional' means that this species is highly to moderately invasive but still with a potential to spread (WNPS Exotic Pest Plants of Greatest Concern). It appears that this species is most problematic in Oregon and Washington as other western states simply report it, but don't mention it as invasive. In California Hickman et al. (1993) says that it occurs in distributed places, but don't mention how common it is. In Colorado, this species was recently discovered as a weed in disturbed places in the plains (Weber 1996). In Utah, it is reported in three counties without mention of abundance (Welsh et al. 1993).

8. Proportion of Nation's Biogeographic Units Invaded:Low significance
Comments: Apera interrupta occurs throughout much of the western United States and in a few states in the mid west and east (TNC 2001).

9. Diversity of Habitats or Ecological Systems Invaded in Nation:Medium/Low significance
Comments: Apera interrupta, has been definitively recorded in disturbed places in the plains of Colorado (Weber and Whitman 1996), in greasewood communities in Utah (Welsh et al. 1993) and in disturbed places in California (Hickman et al. 1993). One study reported it from a variety of soils including lime pavement, saline flats, sandy soils, wasteland, rocky flats, and moist stream banks (NYFA Newsletter 1992), but these reports are from Europe and the United States.

Subrank III. Trend in Distribution and Abundance: Medium/Insignificant

10. Current Trend in Total Range within Nation:Medium/Low significance
Comments: This species is present throughout much of the west and known from New York in the east. It appears to be most invasive in Oregon and Washington where it is reported as 'most invasive - regional' and highly to moderately invasive but still with the potential to spread (WNPS Exotic Pest Plants of Greastest Ecological Concern 1997). Other floras mention that this species occurs in disturbed places (Weber and Whitman 1996, Welsh et al. 1993), so it may spread into natural areas but mostly inhabits disturbed places.

11. Proportion of Potential Range Currently Occupied:Medium/Low significance
Comments: This species is already present in much of the United States and is widespread in the west (Kartesz 1999). It is not clear if this species could spread into the southeast where it is presently absent.

12. Long-distance Dispersal Potential within Nation:Medium/Low significance
Comments: This grass species has been introduced as a contaminant in turf seed in at least part of its range, New York (NYFA Newsletter 1992). It seems that this species is dispersed long distances with the aid of humans.

13. Local Range Expansion or Change in Abundance:High/Low significance
Comments: This species is considered 'most invasive - regional' and highly to moderately invasive but still with the potential to spread in Oregon and Washington (WNPS Exotic Pest Plants of Greastest Ecological Concern 1997).

14. Inherent Ability to Invade Conservation Areas and Other Native Species Habitats:Low significance/Insignificant
Comments: This species has been introduced in at least part of the United States through contaminated turf seed (NYFA Newsletter 1992). Several of the floras where this species is known to occur report that is in disturbed places (Hickman et al. 1993, Welsh et al. 1993, Weber and Whitman 1996).

15. Similar Habitats Invaded Elsewhere:Unknown

16. Reproductive Characteristics:Insignificant
Comments: No information was found suggesting this species has reproductive characteristics that make it an aggresive invader. It reproduces by seed (Welsh et al. 1993).

Subrank IV. General Management Difficulty: Unknown

17. General Management Difficulty:Unknown

18. Minimum Time Commitment:Unknown

19. Impacts of Management on Native Species:Unknown

20. Accessibility of Invaded Areas:Unknown
Authors/Contributors
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Botanical data developed by NatureServe and its network of natural heritage programs (see Local Programs), The North Carolina Botanical Garden, and other contributors and cooperators (see Sources).

References
Help
  • Hickman, J. C., ed. 1993. The Jepson manual: Higher plants of California. University of California Press, Berkeley, CA. 1400 pp.

  • Kartesz, J.T. 1994. A synonymized checklist of the vascular flora of the United States, Canada, and Greenland. 2nd edition. 2 vols. Timber Press, Portland, OR.

  • Kartesz, J.T. 1999. A synonymized checklist and atlas with biological attributes for the vascular flora of the United States, Canada, and Greenland. First edition. In: Kartesz, J.T., and C.A. Meacham. Synthesis of the North American Flora, Version 1.0. North Carolina Botanical Garden, Chapel Hill, N.C.

  • NYFA Newsletter. 1992. New York Flora Association of the New York State Museum Institute. edited by R. S. Mitchell and R. E. Zaremba. Vol. 3. no. 2. Albany, NUY.

  • The Nature Conservancy. 2001. Map: TNC Ecoregions of the United States. Modification of Bailey Ecoregions. Online . Accessed May 2003.

  • Washington Native Plant Society (WNPS). 1997. Preliminary List of Exotic Pest Plants of Greatest Ecological Concern in Oregon and Washington. ONLINE. http://www.wnps.org/eppclist.html. Accessed 2004, January.

  • Weber, W.A., and R.C. Wittmann. 1996a. Colorado flora: Eastern slope. Revised edition. Univ. Press of Colorado, Niwot, Colorado. 524 pp.

  • Welsh, S.L., N.D. Atwood, S. Goodrich, and L.C. Higgins (eds.) 1993. A Utah flora. 2nd edition. Brigham Young Univ., Provo, Utah. 986 pp.

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