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SUMMARY

Rating	Alert	Impact	Invasiveness	Distribution	Doc.
High	Y	A	A	C	3.5
Comments:
Rating 1 = High 2 = Moderate 3 = Limited 4 = Evaluated, not listed		Alert Y = Yes N = No	Scores A = Severe B = Moderate C = Limited D = None U = Unknown	Documentation 4 = Reviewed scientific publications 3 = Other published material 2 = Observational 1 = Anecdotal 0 = No information

Scores

1.1	1.2	1.3	1.4	2.1	2.2	2.3	2.4	2.5	2.6	2.7	3.1	3.2
A	A	A	D	A	A	C	A	A	A	A	C	D

IMPACT

1.1 Impact on abiotic ecosystem processes - A

Identify ecosystem processes impacted: Research indicates that cogongrass contains allopathic substances that may inhibit germination and seedling growth for adjacent grasses. Cogongrass is documented to reduce soil pH thus increasing soil acidity and suppressing growth of surrounding species. Soil nitrate levels are also found to be lower in cogongrass infested areas, and this is attributed to the aggressive growth pattern, extensive rhizome system, and long growing season of this species. Lower nutrient levels can impede the establishment and success of native species.

Cogongrass can alter fire regimes by increasing fire intensity and duration. It can also increase a fire's rate of spread and can induce crown fires, which destroy mature stands of timber.

Sources of information: Collins, A. 2005. Implications of plant diversity and soil chemistry properties for cogongrass (Imperata cylindrica) invasion in northwest Florida. University of Florida. Masters Thesis.

Eussen, J., and S. Wirjahardja. 1973. Studies of an alang-alang, Imperata cylindrical (L.) Beauv. Vegetation. Biotropica Bull. No.6.

Howard, Janet L. 2005. Imperata brasiliensis, I. cylindrica. In: Fire Effects Information System, [Online]. U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station, Fire Sciences Laboratory (Producer). Available: http://www.fs.fed.us/database/feis/ [2013, January 20].

Koger, C.H. and C. T. Bryson. 2004. Effect of cogongrass (Imperata cylindrica) extracts on germination and seedling growth of selected grass and broadleaf species. Weed Technology 18: 236-242.

Documentation: Rev'd Sci. Pub'n

1.2 Impact on plant community composition, structure, and interactions - A

Identify type of impact or alteration: Cogongrass is a C4 perennial grass that is documented to out-compete native species, create monocultures, and increase fire intensity in forested areas. Cogongrass has a high ability to extract soil moisture from shallow soil layers making it difficult for other, potentially more desirable, perennial grasses to become established. Species that can out-compete cogongrass have a deeper root system and a potentially taller canopy. These interactions can disrupt natural successional cycles and alter plant community composition.

Cogongrass can also impact adjacent plants through physical injury, as the hard pointed rhizomes can penetrate the roots, bulbs and tubers of other species. Cogongrass is a fire-adapted species and is capable of growing in moderately shaded areas. It is documented to increase fire duration and intensity. This increase can kill native species, limit secondary succession, increase cogongrass dominance, and further alter plant diversity and composition.

Sources of information: Bryson, C.T. and R. Carter. 1993. Cogongrass, Imperata cylindrica, in the United States. Weed Technol. 7:1005-1009.

Faircloth, W., Patterson, M., Miller, J., Teem, D. and T. Gregory. 2002. Wanted dead or alive: Cogongrass [Online]. Auburn University, Department of Agronomy and Soils. Available: http://www.ag.auburn.edu/agrn/cogongrass/cogongrass fact sheet.htm [2013,January 20].

MacDonld, G. Cogongrass (Imperata cylindrica): Biology, Distribution and Impacts in the Southeastern U.S., [Online]. University of Florida, Department of Agronomy, Institute of Food and Agricultural Sciences. Available: http://www.cogongrass.org/conference07/macdonald.pdf [2013, January 20].

Documentation: Rev'd Sci. Pub'n

1.3 Impact on higher trophic levels - A

Identify type of impact or alteration: Cogongrass increases fire intensity in pine-based ecosystems up to 15 – 20%. This alters secondary succession, and potentially reduces forage foods, refugia, and nesting habitat for insects, birds and mammals. Increased fire intensity may also result in mortality of higher trophic level species.

Cogongrass stands are considered poor habitat for most southeastern wildlife species, as it generally grows taller (3x) than native grasses. This height increase may disrupt the above-ground movement of small animals, while its dense rhizomes can displace ground-dwelling species. Studies indicate that in central Florida habitat quality of two keystone animals, gopher tortoises and scarab beetles, is reduced in cogongrass-invaded sites compared to un-invaded sites.

Sources of information: Gabel, M. L. 1982. A biosystematic study of the genus Imperata (Gramineae: Andropogoneae). Ames, IA: Iowa State University. 90 p. Dissertation.

Howard, Janet L. 2005. Imperata brasiliensis, I. cylindrica. In: Fire Effects Information System, [Online]. U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station, Fire Sciences Laboratory (Producer). Available: http://www.fs.fed.us/database/feis/ [2013, January 20].

Johnson, E. R., Shilling, D. and G. Donn. 2004. Fact sheet: Cogon grass-Imperata cylindrica (L.) Palisot, [Online]. In: Weeds gone wild: Alien plant invaders of natural areas. Plant Conservation Alliance, Alien Plant Working Group (Producer). Available: http://www.nps.gov/plants/alien/fact/imcyl.htm [2013, January 20].

Lippincott, C.L. 2000. Effects of Imperata cylindrica (L.) Beauv. (cogongrass) invasion on fire regime in Florida sandhill. Nat. Area. J. 20:140-149.

MacDonld, G. Cogongrass (Imperata cylindrica): Biology, Distribution and Impacts in the Southeastern U.S. [Online]. University of Florida, Department of Agronomy, Institute of Food and Agricultural Sciences. Available: http://www.cogongrass.org/conference07/macdonald.pdf [2013, January 20].

Documentation: Rev'd Sci. Pub'n

1.4 Impact on genetic integrity - D

Identify impacts: Cogongrass is genetically and morphologically similar to Imperata brasiliensis, and hybridization with this species is common. Hybrids are capable of producing viable offspring. However, I. brasiliensis is also a nonnative species; there are no known occurrences of hybridization with native species.

Sources of information: Howard, Janet L. 2005. Imperata brasiliensis, I. cylindrica. In: Fire Effects Information System, [Online]. U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station, Fire Sciences Laboratory (Producer). Available: http://www.fs.fed.us/database/feis/ [2013, January 20].

Documentation: Other Pub. Mat’l

IMPACT: A A A D = A

INVASIVENESS

2.1 Role of anthropogenic and natural disturbance in establishment - A

Describe role of disturbance: Cogongrass can become established in disturbed and undisturbed areas. It is documented to rapidly invade disturbed areas, specifically those cultivated or tilled for row crop production and construction of right-of-ways.

In its native range, cogongrass colonizes areas following a climax event, usually a fire, and populations decline upon canopy closure. However, in the U.S., it continues to thrive because invaded forests of the southeast generally have a more open canopy cover (i.e., pine dominated) and due to forest management practices.

Sources of information: Bryson, C.T. and R. Carter. 1993. Cogongrass, Imperata cylindrica, in the United States. Weed Technol. 7:1005- 1009.

Howard, Janet L. 2005. Imperata brasiliensis, I. cylindrica. In: Fire Effects Information System, [Online]. U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station, Fire Sciences Laboratory (Producer). Available: http://www.fs.fed.us/database/feis/ [2013, January 20].

Documentation: Rev'd Sci. Pub'n

2.2 Local rate of spread with no management - A

Describe rate of spread: Cogongrass is a prolific seeder and rhizomes have an aggressive asexual regenerative capacity. In established populations, rhizomes are the primary method of localized spread. They are also believed to be primarily responsible for the establishment of new populations, as rhizome pieces spread in contaminated fill dirt.

Sources of information: Dozier, H., James, F., Gaffney, S., McDonald, E., Johnson, R., and D. Shilling. 1998. Cogongrass in the United States: History, Ecology, Impacts, and Management. Weed Technology, Vol. 12, No. 4 (Oct. - Dec., 1998), pp.737-743.

Patterson, D. T and C. G. McWhorter. 1980. Distribution and control of cogongrass Imperata cylindrica in Mississippi. Proc. South. Weed Sci. Soc. 33:251.

Documentation: Rev'd Sci. Pub'n

2.3 Recent trend in total area infested within state - C

Describe trend: Currently, there are no known populations of cogongrass in Texas. In 2006 a five to six acre population was found in East Texas. This population was treated, and has been preventively treated every year since.

Sources of information: Observation: M. Murphrey (Texas Forest Service), 2013.

Documentation: Observational

2.4 Innate reproductive potential - A

Describe key reproductive characteristics: Refer to Worksheet A.

Sources of information: Collins, A. 2005. Implications of plant diversity and soil chemistry properties for cogongrass (Imperata cylindrica) invasion in northwest Florida. University of Florida. Masters Thesis.

Dozier, H., James, F., Gaffney, S., McDonald, E., Johnson, R., and D. Shilling. 1998. Cogongrass in the United States: History, Ecology, Impacts, and Management. Weed Technology, Vol. 12, No. 4 (Oct. - Dec., 1998), pp. 737-743.

Howard, Janet L. 2005. Imperata brasiliensis, I. cylindrica. In: Fire Effects Information System, [Online]. U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station, Fire Sciences Laboratory (Producer). Available: http://www.fs.fed.us/database/feis/ [2013, January 20].

Documentation: Rev'd Sci. Pub'n

2.5 Potential for human-caused dispersal - A

Identify dispersal mechanisms: Cogongrass rhizomes may be transported via contaminated fill dirt or machinery. Roads and road construction are important corridors for dispersal. It is also dispersed as an ornamental.

Sources of information: Dozier, H., James, F., Gaffney, S., McDonald, E., Johnson, R., and D. Shilling. 1998. Cogongrass in the United States: History, Ecology, Impacts, and Management. Weed Technology, Vol. 12, No. 4 (Oct. - Dec., 1998), pp.737-743.

Howard, Janet L. 2005. Imperata brasiliensis, I. cylindrica. In: Fire Effects Information System, [Online]. U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station, Fire Sciences Laboratory (Producer). Available: http://www.fs.fed.us/database/feis/ [2013, January 20].

Patterson, D. T and C. G. McWhorter. 1980. Distribution and control of cogongrass Imperata cylindrica in Mississippi. Proc. South. Weed Sci. Soc. 33:251.

Documentation: Rev'd Sci. Pub'n

2.6 Potential for natural long-distance dispersal - A

Identify dispersal mechanisms: Long-distance dispersal is common, as cogongrass seeds are light-weight with long hairy plumes aiding in distribution. Studies indicate that wind can disperse seeds up to 15 miles in open areas, and move spikelets up to 360 feet from the parent plant.

Sources of information: Gabel, M. L. 1982. A biosystematic study of the genus Imperata (Gramineae: Andropogoneae). Ames, IA: Iowa State University. 90 p. Dissertation.

Howard, Janet L. 2005. Imperata brasiliensis, I. cylindrica. In: Fire Effects Information System, [Online]. U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station, Fire Sciences Laboratory (Producer). Available: http://www.fs.fed.us/database/feis/ [2013, January 20].

Shilling, D. G., Bewick, T. A., Gaffney, J. F., McDonald, S. K., Chase, C. A. and E. R. R. L Johnson. 1997. Ecology, physiology, and management of cogongrass (Imperata cylindrica). Publication No. 03-107-140. Gainesville, FL: University of Florida. p. 128.

Documentation: Rev’d Sci. Pub’n

2.7 Other regions invaded - A

Identify other regions: Cogongrass grows in tropical and sub-tropical regions, and is considered a federal noxious weed throughout the southeastern U.S. This ecotype is most similar to our Coastal Prairies and East Texas Piney Woods, though cogongrass may become established in other Texas ecoregions and riparian areas.

Sources of information: Howard, Janet L. 2005. Imperata brasiliensis, I. cylindrica. In: Fire Effects Information System, [Online]. U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station, Fire Sciences Laboratory (Producer). Available: http://www.fs.fed.us/database/feis/ [2013, January 20].

Documentation: Other Pub. Mat'l

INVASIVENESS: A A C A A A A = A

DISTRIBUTION

3.1 Ecological amplitude - C

Describe ecological amplitude, identifying date of source information and approximate date of introduction to the state, if known: Refer to Worksheet B.

Sources of information: Invaders of Texas Citizen Science Program, Citizen Scientist Observations [Online]. Available: http://texasinvasives.org/observations/search.php?satellite=&sn=&cn=IMCY [2013, January 21].

USDA PLANTS Database [Online]. Available: http://plants.usda.gov/java/profile?symbol=IMCY [2013,January 21].

Observational: M. Murphrey (Texas Forest Service), 2013.

Documentation: Other Pub. Mat’l

3.2 Distribution/Peak frequency - D

Identify type of impact or alteration: Refer to Worksheet B.

Sources of information: Invaders of Texas Citizen Science Program, Citizen Scientist Observations [Online]. Available: http://texasinvasives.org/observations/search.php?satellite=&sn=&cn=IMCY [2013, January 21].

USDA PLANTS Database [Online]. Available: http://plants.usda.gov/java/profile?symbol=IMCY [2013, January 21].

Observational: M. Murphrey (Texas Forest Service), 2013

Documentation: Other Pub. Mat’l

IMPACT: C D = C

TEXAS ECOREGIONS

Source: Level III and IV Ecoregions of Texas. Griffith, G.E., Bryce, S.A., Omernik, J.M., Comstock, J.A., Rogers, A.C., Harrison, B., Hatch, S.L., and Bezanson, D., 2004, Ecoregions of Texas, U.S. Environmental Protection Agency, Corvallis, OR.

Score: A. means >50% of type occurrences are invaded; B means >20% to 50%; C. means >5% to 20%; D. means present but ≤5%; U. means unknown.

Code	Level III	Level IV	Score
ER01	Arizona/New Mexico Mountains	Chihuahuan Desert Slopes
		Montane Woodlands
ER02	Chihuahuan Deserts	Chihuahuan Basins and Playas
		Chihuahuan Desert Grasslands
		Low Mountains and Bajadas
		Chihuahuan Montane Woodlands
		Stockton Plateau
ER03	High Plains	Rolling Sand Plains
		Canadian/Cimarron High Plains
		Llano Estacado
		Shinnery Sands
		Arid Llano Estacado
ER04	Southwestern Tablelands	Canadian/Cimarron Breaks
		Flat Tablelands and Valleys
		Caprock Canyons, Badlands, and Breaks
		Semiarid Canadian Breaks
ER05	Central Great Plains	Red Prairie
		Broken Red Plains
		Limestone Plains
ER06	Cross Timbers	Eastern Crosstimbers
		Western Crosstimbers
		Grand Prairie
		Limestone Cut Plain
		Carbonate Cross Timbers
ER07	Edwards Plateau	Edwards Plateau Woodland
		Llano Uplift
		Balcones Canyonlands
		Semiarid Edwards Plateau
ER08	Southern Texas Plains	Northern Nueces Alluvial Plains
		Semiarid Edwards Bajadas
		Texas-Tamaulipan Thornscrub
		Rio Grande Floodplain and Terraces
ER09	Texas Blackland Prairies	Northern Blackland Prairies
		Southern Blackland/Fayette Prairie
		Floodplains and Low Terraces
ER10	East Central Texas Plains	Northern Post Oak Savanna
		Southern Post Oak Savanna
		San Antonio Prairie	D
		Northern Prairie Outliers
		Bastrop Lost Pines
		Floodplains and Low Terraces
ER11	Western Gulf Coastal Plain	Northern Humid Gulf Coastal Prairies
		Southern Subhumid Gulf Coastal Prairies
		Floodplains and Low Terraces
		Coastal Sand Plain
		Lower Rio Grande Valley
		Lower Rio Grande Alluvial Floodplain
		Texas-Louisiana Coastal Marshes
		Mid-Coast Barrier Islands and Coastal Marshes
		Laguna Madre Barrier Islands and Coastal Marshes
ER12	South Central Plains	Tertiary Uplands
		Floodplains and Low Terraces
		Pleistocene Fluvial Terraces
		Southern Tertiary Uplands
		Flatwoods	D
		Red River Bottomland

EVALUATORS

Evaluation Date: 2013-01-20

Evaluator 1
Jessica Strickland, Ecologist
The Lady Bird Johnson Wildflower Center at UT-Austin
512-232-0107
jstrickland@wildflower.org
4801 LaCrosse Ave Austin, TX 78739

Evaluator 2
Tara Raabe/Ecologist
ARCADIS-US
512-527-6070
Tara.Raabe@arcadis-us.com
1717 West 6th Street, Suite 210 Austin, TX 78703

REVIEW

Reviewers: Damon Waitt, Scott Walker
Review Date: 2013-01-30
Comments:

Evaluation 1 & 2: The Texas Invasive Plant and Pest Council (TIPPC) is proposing to the Texas Invasive Species Coordinating Committee to add Imperata cylindrica to the Texas Department of Agriculture Noxious and Invasive Plant List (Texas Administrative Code: Title 4, Part 1, Chapter 19, Subchapter T, Rule: §19.300). The Weed Risk Assessment is a supporting document for species proposal submission.

REFERENCES

Bryson, C.T. and R. Carter. 1993. Cogongrass, Imperata cylindrica, in the United States. Weed Technol. 7:1005- 1009.

Collins, A. 2005. Implications of plant diversity and soil chemistry properties for cogongrass (Imperata cylindrica) invasion in northwest Florida. University of Florida. Masters Thesis.

Dozier, H., James, F., Gaffney, S., McDonald, E., Johnson, R., and D. Shilling. 1998. Cogongrass in the United States: History, Ecology, Impacts, and Management. Weed Technology, Vol. 12, No. 4 (Oct. - Dec., 1998), pp. 737-743.

Eussen, J., and S. Wirjahardja. 1973. Studies of an alang-alang, Imperata cylindrica (L.) Beauv. Vegetation. Biotropica Bull. No.6.

Faircloth, W., Patterson, M., Miller,J., Teem, D. and T. Gregory. 2002. Wanted dead or alive: Cogongrass, [Online]. Auburn University, Department of Agronomy and Soils. Available: http://www.ag.auburn.edu/agrn/cogongrass/cogongrass fact sheet.htm [2013, January 20].

Gabel, M. L. 1982. A biosystematic study of the genus Imperata (Gramineae: Andropogoneae). Ames, IA: Iowa State University. 90 p. Dissertation.

Howard, Janet L. 2005. Imperata brasiliensis, I. cylindrica. In: Fire Effects Information System, [Online]. U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station, Fire Sciences Laboratory (Producer). Available: http://www.fs.fed.us/database/feis/ [2013, January 20].

Invaders of Texas Citizen Science Program, Citizen Scientist Observations [Online]. Available: http://texasinvasives.org/observations/search.php?satellite=&sn=&cn=IMCY [2013, January 21].

Johnson, E. R., Shilling, D. and G. Donn. 2004. Fact sheet: Cogon grass-Imperata cylindrica (L.) Palisot, [Online]. In: Weeds gone wild: Alien plant invaders of natural areas. Plant Conservation Alliance, Alien Plant Working Group (Producer). Available: http://www.nps.gov/plants/alien/fact/imcyl.htm [2013, January 20].

Koger, C.H. and C. T. Bryson. 2004. Effect of cogongrass (Imperata cylindrica) extracts on germination and seedling growth of selected grass and broadleaf species. Weed Technology 18: 236-242.

Lippincott, C.L. 2000. Effects of Imperata cylindrica (L.) Beauv. (cogongrass) invasion on fire regime in Florida sandhill. Nat. Area. J. 20:140-149.

MacDonld, G. Cogongrass (Imperata cylindrica): Biology, Distribution and Impacts in the Southeastern U.S., [Online]. University of Florida, Department of Agronomy, Institute of Food and Agricultural Sciences. Available: http://www.cogongrass.org/conference07/macdonald.pdf [2013, January 20].

Patterson, D. T and C. G. McWhorter. 1980. Distribution and control of cogongrass Imperata cylindrica in Mississippi. Proc. South. Weed Sci. Soc. 33:251.

Shilling, D. G., Bewick, T. A., Gaffney, J. F., McDonald, S. K., Chase, C. A. and E. R. R. L Johnson. 1997. Ecology, physiology, and management of cogongrass (Imperata cylindrica). Publication No. 03-107-140. Gainesville, FL: University of Florida. p. 128.

USDA PLANTS Database [Online]. Available: http://plants.usda.gov/java/profile?symbol=IMCY [2013,January 21].