Potentially Misidentified Species:
Identification of grasses in general is often difficcult, usually relying on detailed examination of of the rhizomes, leaves, and inflorescence.
II. HABITAT AND DISTRIBUTION
Native to Africa, Urochloa mutica has been collected from several
U.S. states including Alabama, Florida, Hawaii, South Carolina, and Texas.
In peninsular Florida, para grass is a widespread marginal plant found around lakes, marshes and rivers (Richerson and Jacono 2003).
Urochloa mutica is established in most central and south Florida
counties. The FLEPPC Early Detection and Distribution (EDD) Mapping System
indicates that positive occurrence records for para grass exist for all IRL
watershed counties except St. Lucie County.
III. LIFE HISTORY AND POPULATION BIOLOGY
Age, Size, Lifespan:
Urochloa mutica is a perennial grass that can reach 2 m in height, although 1 m is more common.
Richerson and Jacono (2003) report that Urochloa mutica is established
and abundant throughout peninsular Florida drainages, and is especiallly
problematic in drainage canals. These authors note that several thousand para
grass-infested hectares of land around Lake Okeechobee have burned in past
Urochloa mutica can reproduce sexually from seed, but more important is
its ability to reproduce vegetatively by means of its above-ground creeping
stolons (Tarver et al. 1986, Hoyer et al. 1996).
Although Urochloa mutica has been characterized as a prolific seed
producer (> 1,000 seeds per square meter), the germination rate is usually
extremely low (Smith 1973).
IV. PHYSICAL TOLERANCES
Urochloa mutica thrives under warm, moist conditions, and is extremely
frost intolerant. Wheeler (1950) indicates para grass will not persist at
temperatures lower than 8°C. Allen and Cowdry (1961) indicate a minimum
temperature for growth of 15°C and Russell and Webb note that 21°C is the optimum
mean growth temperature.
Urochloa mutica grows best under high rainfall conditions in the tropics
and subtropics. It can survive seasonal dry conditions by relying on the
residual moisture of the marshy habitats it prefers (FAO).
V. COMMUNITY ECOLOGY
Although Urochloa mutica is quite capable of displacing co-occurring
plants, it often does grade into stands of other species, e.g., along an upward distribution
from marsh to more upland habitat.
VI. INVASION INFORMATION
The exotic grass Urochloa mutica is native to Africa where it has a long
history of cultivation as a forage species. It was intentionally introduced to
the U.S. for this purpose, initially in the 1870s (Austin 1978). It has since
escaped cultivation and has become established throughout most of peninsular
Florida. It thrives particularly well in agricultural lands and other
disturbed habitats (Godfrey and Wooten 1979).
Austin (1978) notes that para grass was employed as camouflage around military installations in south Florida during
World War II.
Potential to Compete With Natives:
Though most often found in human-altered habitats, Urochloa mutica is a
vigorous plant and is capable of displacing significant amounts of native
vegetation. Concern over the potential ecological impact of para grass is
warranted given the number of Florida wetland ecosystems in which the species
may thrive if it gains a foothold (Austin 1978).
Possible Economic Consequences of Invasion:
Para grass has proved to be an aggressive invader of human-altered habitats in
Florida, particularly low-lying ungrazed pastureland and in sugar cane fields.
Marginal stands and floating mats of para grass can slow of clog drainage
ditches and irrigation canals, and may also impede the navigation of small
craft in shallow waterways (Austin 1978, Tarver et al. 1986, Hoyer et al.
Allen G.H., and W.A.R. Cowdry. 1961. Yield from irrigated pasture in Burdekin,
Queensland. Agricultural Journal 87:207-13.
Austin D.F. 1978. Exotic plants and their effects in southeastern Florida.
Environmental Conservation 5:25-34.
Godfrey R.K., and J.W. Wooten. 1979. Aquatic and Wetland Plants of Southeastern
United States. Monocotyledons. The University of Georgia Press, Athens,
Georgia. 933 p.
Hoyer M.V., Canfield D.E., Jr., Horsburgh C.A., and K. Brown. 1996. Florida
Freshwater Plants - A Handbook of Common Aquatic Plants in Florida Lakes.
University of Florida, Institute of Food and Agricultural Sciences,
Gainesville, Florida. 264 p.
Richerson M.M., and C.C. Jacono. 2003. Urochloa (Brachiaria)
mutica (Forsk.) T.Q. Nguyen. USGS Nonindigenous Aquatic Species fact
sheet. Available online.
Russell J.S., and H.R. Webb. 1976. Climatic range of grasses and legumes used
in pastures. Result of a survey conducted at the 11th International Grassland
Congress. J. Aust. Inst. Agri. Sci., 42:156-163.
Smith R.N.W. 1973. Para grass in Northern Territory -parantage and propogation.
Tropical Grasslands Vol 7249-250.
Tarver D.P., Rogers J.A.,. Mahler M.J, and R.L. Lazor. 1986. Aquatic and
Wetland Plants of Florida. Third Edition. Florida Department of Natural
Resources, Tallahassee, Florida. 127 p.
Wheeler W.A. 1950. Forage and Pasture Crops. van Nostrand Publishers, New
Jersey. 752 p.
J. Masterson, Smithsonian Marine Station
Submit additional information, photos or comments
Page last updated: December 1, 2007