Agrostis gigantea - Roth
Giant Bentgrass
Other English Common Names: Black Bent, Black Bentgrass, Redtop
Other Common Names: redtop
Taxonomic Status: Accepted
Related ITIS Name(s): Agrostis gigantea Roth (TSN 40414)
Unique Identifier: ELEMENT_GLOBAL.2.161505
Element Code: PMPOA040H0
Informal Taxonomy: Plants, Vascular - Flowering Plants - Grass Family
 
Kingdom Phylum Class Order Family Genus
Plantae Anthophyta Monocotyledoneae Cyperales Poaceae Agrostis
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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: Agrostis gigantea
Conservation Status
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NatureServe Status

Global Status: G4G5
Global Status Last Reviewed: 04Aug1988
Global Status Last Changed: 04Aug1988
Rounded Global Status: G4 - Apparently Secure
Nation: United States
National Status: NNA
Nation: Canada
National Status: NNA (28Sep2016)

U.S. & Canada State/Province Status
United States Alabama (SNA), Alaska (SNA), Arizona (SNA), Arkansas (SNA), California (SNA), Colorado (SNA), Connecticut (SNA), Delaware (SNA), District of Columbia (SNA), Florida (SNA), Georgia (SNA), Idaho (SNA), Illinois (SNA), Indiana (SNA), Iowa (SNA), Kansas (SNA), Kentucky (SNA), Louisiana (SNA), Maine (SNA), Maryland (SNA), Massachusetts (SNR), Michigan (SNA), Minnesota (SNA), Mississippi (SNA), Missouri (SNA), Montana (SNA), Nevada (SNA), New Hampshire (SNA), New Jersey (SNA), New Mexico (SNA), New York (SNA), North Dakota (SNA), Ohio (SNA), Oklahoma (SNA), Oregon (SNA), Pennsylvania (SNA), Rhode Island (SNA), Tennessee (SNA), Utah (SNA), Vermont (SNA), Virginia (SNA), Washington (SNA), West Virginia (SNA), Wisconsin (SNA), Wyoming (SNA)
Canada Alberta (SNA), British Columbia (SNA), Manitoba (SNA), New Brunswick (SNA), Newfoundland Island (SNA), Northwest Territories (SNA), Nova Scotia (SNA), Ontario (SNA), Prince Edward Island (SNA), Quebec (SNA), Saskatchewan (SNA), Yukon Territory (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 AKexotic, ALexotic, ARexotic, AZexotic, CAexotic, COexotic, CTexotic, DCexotic, DEexotic, FLexotic, GAexotic, IAexotic, IDexotic, ILexotic, INexotic, KSexotic, KYexotic, LAexotic, MA, MDexotic, MEexotic, MIexotic, MNexotic, MOexotic, MSexotic, MTexotic, NDexotic, NHexotic, NJexotic, NMexotic, NVexotic, NYexotic, OHexotic, OKexotic, ORexotic, PAexotic, RIexotic, TNexotic, UTexotic, VAexotic, VTexotic, WAexotic, WIexotic, WVexotic, WYexotic
Canada ABexotic, BCexotic, MBexotic, NBexotic, NFexotic, NSexotic, NTexotic, ONexotic, PEexotic, QCexotic, SKexotic, YTexotic

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/Low
Rounded I-Rank: Medium
I-Rank Reasons Summary: Agrostis gigantea occurs across the U.S. but is less frequent in the Southeast. It is often planted as a soil stabilizer and is also used as pasture and turf. Although it is most frequent in disturbed areas, it is also reported from relatively undisturbed bogs, shores, woods, and dunes in Michigan. It occurs adjacent to, but is apparently not invading into, old-growth forests in the Adirondacks and temperate rainforest in Olympic National Park. Other native species habitats include Allegheny Plateau riparian forest, wet to moist meadows, Southern Appalachian grass balds, and coastal marshes. Agrostis gigantea exhibits aggressive reproductive characters. The thick turf produced by Agrostis gigantea was shown to be a barrier to the establishment of small seeded native tree species. Management is currently not extremely difficult but may become more difficult in the future if glyphosate-resistant creeping bentgrass is commercially released. There is the potential for unintended transfer of the resistance gene to this related species.
Subrank I - Ecological Impact: Low
Subrank II - Current Distribution/Abundance: High/Medium
Subrank III - Trend in Distribution/Abundance: Medium/Low
Subrank IV - Management Difficulty: Medium/Insignificant
I-Rank Review Date: 26Apr2007
Evaluator: Tomaino, A.
Native anywhere in the U.S?
Native Range: Temperate Asia, Europe, India, Nepal, and Pakistan (USDA 2007).

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Screening Questions

S-1. Established outside cultivation as a non-native? YES
Comments: Established outside cultivation in the U.S. (Kartesz 1999).

S-2. Present in conservation areas or other native species habitat? Yes
Comments: Occurs in fields, roadsides, ditches, and other disturbed habitats, mostly at lower elevations (FNA 2007).

Subrank I - Ecological Impact: Low

1. Impact on Ecosystem Processes and System-wide Parameters:Insignificant
Comments: No mention of changes in abiotic ecosystem processes or system-wide parameters found in the literature; assumption is that any alterations are not significant.

2. Impact on Ecological Community Structure:Low significance
Comments: The thick turf produced by Agrostis gigantea was found to be a barrier to the establishment of small seeded native tree species (Picea sitchensis, Tsuga heterophylla, and Alnus rubra) in an old field adjacent to temperate rainforest in Olympic National Park, Washington (Riege and Del Moral 2004). Turf forming grasses create a dense sod of matted roots, thatch and thick cover (Riege and Del Moral 2004).

3. Impact on Ecological Community Composition:Moderate significance
Comments: Highly competitve with native species (CNPS 2002). Competition from the sod-forming Agrostis gigantea, appears to have caused the death of Picea sitchensis seedlings in an old field adjacent to temperate rain forest in Olympic National Park, Washington; Picea sitchensis sapling colonization was negatively correlated with percent cover of Agrostis gigantea (Riege and Del Moral 2004).

4. Impact on Individual Native Plant or Animal Species:Low significance
Comments: Although Picea sitchensis sapling colonization was negatively correlated with percent cover of Agrostis gigantea (Riege and Del Moral 2004) this does not appear to be an unusual disproportionate impact. Assumption is that any impacts are not high or moderate.

5. Conservation Significance of the Communities and Native Species Threatened:Medium/Low significance
Comments: In Michigan, it occurs in relatively undisturbed bogs, shores, woods, and dunes (Voss 1972). In the Allegheny Plateau, it occurs in riparian forest (Hanlon et al. 1998). It occurs adjacent to (but not in) old growth forest in the Adirondacks (Mitchell and Tucker 1994). Also found in wet to moist meadows, riparian communities, open forest, and southern Appalachian grass balds (Carey 1995). In an old field adjacent to temperate rainforest in Washington state (Riege and Del Moral 2004). Some of these communities may be of conservation significance or harbor species of conservation significance but apparently it is not often threatening elements of conservation significance.

Subrank II. Current Distribution and Abundance: High/Medium

6. Current Range Size in Nation:High significance
Comments: Established in every U.S. state with the possible exception of South Dakota and Nebraska but less frequent in the southeast (J. Kartesz, unpublished data; Carey 1995).

7. Proportion of Current Range Where the Species is Negatively Impacting Biodiversity:Medium/Low significance
Comments: Reported to be invasive in Oregon, New York, Virginia, and Tennessee (Swearingen 2007). Having a negative impact on native tree species succession in an old field adjacent to temperate rainforest in Washington state (Riege and Del Moral 2004). Present adjacent to but apparently not invading into old growth forest in New York (Mitchell and Tucker 1994). Occurs in riparian forest in the Alleghany Plateau (Hanlon et al. 1998).

8. Proportion of Nation's Biogeographic Units Invaded:High significance
Comments: Inferred from distribution as currently understood (J. Kartesz, unpublished data; TNC 2001).

9. Diversity of Habitats or Ecological Systems Invaded in Nation:High/Moderate significance
Comments: Occurs in fields, roadsides, ditches, and other disturbed habitats, mostly at lower elevations (FNA 2007). Occurs in moist meadows, shores, coastal marshes, and other moist places (Gleason and Cronquist 1991). In California, it occurs in roadsides, fields, ditches, and disturbed areas (Baldwin et al. 2007). In Michigan, it occurs in relatively undisturbed bogs, shores, woods, and dunes as well as roadsides and fields (Voss 1972). Found in wet to moist meadows, riparian communities, open forest, and southern Appalachian grass balds (Carey 1995).

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

10. Current Trend in Total Range within Nation:Low significance
Comments: Already very widespread throughout the region (J. Kartesz, unpublished data). Potential for further expansion is probably limited by its biology.

11. Proportion of Potential Range Currently Occupied:Low significance
Comments: Inferred from USDA (1990) and J. Kartesz, unpublished data.

12. Long-distance Dispersal Potential within Nation:High significance
Comments: Sold on the internet. Planted for erosion control, pasture, turf and occasionally hay (NRCS 2002).

13. Local Range Expansion or Change in Abundance:Medium/Low significance
Comments: Occurs in disturbed areas; assumption is that disturbed areas are not decreasing or remaining stable and therefore this species' local range is not decreasing or remaining stable. Since it is already quite widespread (J. Kartesz, unpublished data), assumption is that local range expansion and abundance is not rapid.

14. Inherent Ability to Invade Conservation Areas and Other Native Species Habitats:Medium/Low significance
Comments: Colonizes disturbed sites, such as mudflow from Mt. St. Helens volcanic eruption, recently exposed gravel, and sandbars (Carey 1995). Restricted to the periphery of an old-growth forest in the Adirondacks of New York (Mitchell and Tucker 1994).

15. Similar Habitats Invaded Elsewhere:Medium/Low significance
Comments: Occurs across Canada (Kartesz 1999). In British Columbia, in dry to mesic roadsides, fields, and waste places (Douglas et al. 2001). In Ontario, escaped to roadsides, beaches, waste places, and moist fields (Dorr and McNeill 1980). A tenacious agricultural weed in Australia and New Zealand (Randall 2003).

16. Reproductive Characteristics:High significance
Comments: Reproduces both vegetatively and by seed, has quickly spreading rhizomes, resprouts readily when cut or grazed, and has high seed abundance (USDA, NRCS 2007). Although Agrostis gigantea was common in the extant vegetation of an Alleghaney Plateau riparian forest, its seeds were absent from the seed bank (Hanlon et al. 1998).

Subrank IV. General Management Difficulty: Medium/Insignificant

17. General Management Difficulty:Medium/Low significance
Comments: Is currently well controlled by glyphosate (Hart et al. 2005). If glyphosate-resistant creeping bentgrass is commercially released, there is the potential for unintended transfer of the resistance gene to this related species; future control may be more difficult and expensive (Hart et al. 2005). It may also be controlled by continuous close grazing or mowing (NRCS 2002).

18. Minimum Time Commitment:Medium significance/Insignificant
Comments: No mention of control requiring more than 10 years found in the literature; assumption is that control requires less than 10 years.

19. Impacts of Management on Native Species:Medium/Low significance
Comments: Herbicides may impact non-target species but Agrostis gigantea may be relatively easy to target since it tends to form dense stands of turf (NRCS 2002) with few other species.

20. Accessibility of Invaded Areas:Medium/Low significance
Comments: It is a serious agricultural weed as well as a valuable soil stabilizer (FNA 2007). Assumption is at least in some areas, accessibility may be a problem but problems are not severe or substantial.

Other Considerations: There may be some confusion between Agrostis species in the literature (Carey 1995). Agrostis gigantea may be confused with A. stolonifera, especially if the rootstock is not collected (FNA 2007). A. stolonifera is also widespread and is considered non-native in much of the U.S. (FNA 2007).
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
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  • Baldwin, B., T.J. Rosatti, and M. Wetherwax (eds.). 2007. Second Edition of The Jepson Manual: Vascular Plants of California DRAFT Treatments for public viewing. Available online: http://ucjeps.berkeley.edu/jepsonmanual/review/ . Accessed 2007.

  • Carey, J. H. 1995. Agrostis gigantea. In: Fire Effects Information System. U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station, Fire Sciences Laboratory. Online. Available: http://www.fs.fed.us/database/feis/ (accessed 25 April 2007).

  • Colorado Native Plant Society (CNPS). 2002. May last update. Plant Species to Avoid for Landscaping, Revegetation, and Restoration. Online. Available: http://carbon.cudenver.edu/~shill/pdf/species_avoid.pdf (accessed 2007).

  • Dore, W.G., and J. McNeill. 1980. Grasses of Ontario. Research Branch, Agriculture Cananda, Ottawa. 566 pp.

  • Douglas, G.W., D. Meidinger, and J. Pojar, editors. 2001. The Illustrated Flora of British Columbia. Volume 7. Monocotyledons (Orchidaceae through Zosteraceae). British Columbia Ministry of Environment, Lands and Parks and British Columbia Ministry of Forests, Victoria.

  • Flora of North America Editorial Committee. 2007a. Flora of North America North of Mexico. Vol. 24. Magnoliophyta: Commelinidae (in part): Poaceae, part 1. Oxford Univ. Press, New York. xxviii + 911 pp.

  • Gleason, H.A., and A. Cronquist. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. New York Botanical Garden, Bronx, New York. 910 pp.

  • Hanlon, T. J., C. E. Williams, and W. J. Moriarity. 1998. Species composition of soil seed banks of Allegheny plateau riparian forests. Journal of the Torrey Botanical Society 125(3): 199-215.

  • Hart, S. E., F. Yelverton, E. K. Nelson, D. W. Lycan, G. M. Henry. 2005. Response of glyphosate-resistant and Glyphosate-Susceptible Bentgrass (Agrostis spp.) to postemergence herbicides. Weed Technology 19(3): 549-559.

  • 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.

  • Meades, S.J. & Hay, S.G; Brouillet, L. 2000. Annotated Checklist of Vascular Plants of Newfoundland and Labrador. Memorial University Botanical Gardens, St John's NF. 237pp.

  • Mitchell, R. S., and G. C. Tucker. 1994. Flora of an unusually diverse virgin and old-growth forest area in the southern Adirondacks of New York. Bulletin of the Torrey Botanical Club 121(1): 76-83.

  • Natural Resources Conservation Service (NRCS). 2002. NRCS Plant Fact Sheet for Redtop, Agrostis gigantea Roth. USDA NRCS Plant Materials Program. [http://plants.usda.gov/factsheet/pdf/fs_aggi2.pdf]

  • Randall, R. 2003. November last update. Rod Randall's Big Weed List. Global Invasive Species Initiative, The Nature Conservancy. Online. Available: http://tncweeds.ucdavis.edu/biglist.html. (accessed 2007).

  • Riege, D. A., and R. Del Moral. 2004. Differential tree colonization of old fields in a temperate rain forest. The American Midland Naturalist 151(2): 251-264.

  • Swearingen, J. 2007. Alien plant invaders of natural areas. Plant Conservation Alliance, Alien Plant Working Group. Online. Available: http://www.nps.gov/plants/alien/list/ (accessed 2007)

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  • USDA, NRCS. 2007. The PLANTS Database. Data compiled from various sources by Mark W. Skinner. National Plant Data Center (http://npdc.usda.gov), Baton Rouge, LA. Online. Available: http://plants.usda.gov (Accessed 2007).

  • Voss, E.G. 1972. Michigan flora: A guide to the identification and occurrence of the native and naturalized seed-plants of the state. Part I. Gymnosperms and monocots. Cranbrook Institute of Science and Univ. Michigan Herbarium. Ann Arbor. 488 pp.

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