U.S. Army Corps of Engineers
Fort Worth District
819 Taylor Street
P.O. Box 17300
Fort Worth, TX 76102
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Terrestrial Invasive/Nusiance Species
Japanese Climbing Fern
Feral Hog or Wild Boar
Red Imported Fire Ant
Euphorbiales > Euphorbiaceae > Triadica sebifera (L.) Small
Chris Evans, River to River CWMA, Bugwood.org
Chinese tallowtree invades wet areas such as stream banks and ditches but can also invade drier upland sites. Chinese tallowtree is a serious threat because of its ability to invade high quality, undisturbed forests. It can displace native vegetation as well as alter soil conditions due to the high amount of tannins present in the leaf litter.
Chinese tallowtree is a deciduous tree reaching 60 feet in height and 3 feet in diameter. Flowering occurs from April to June. The flowers are yellowish and occur on 8 inch long dangling spikes. Chinese tallowtree is a native of China and was introduced into South Carolina in 1776 for ornamental purposes and seed oil production.
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Japanese climbing fern
Polypodiales > Lygodiaceae > Lygodium japonicum (Thunb. ex Murr.) Sw.
Ted Bodner, Southern Weed Science Society, Bugwood.org
Japanese climbing fern often invades disturbed areas such as roadsides and ditches, but can also invade natural areas. It generally is scattered throughout the landscape, but can form dense mats that smother understory vegetation, shrubs, and trees.
Japanese climbing fern is a perennial climbing fern that can reach lengths of 90 feet. Vines are thin, wiry, and green to orange to black and usually die back in the winter. Plants spread by rhizomes as well as tiny, wind-dispersed spores. Japanese climbing fern is native to eastern Asia and was first introduced into the United States during the 1930s for ornamental purposes.
Fabales > Fabaceae > Pueraria montana(Lour.) Merr.
Forest & Kim Starr, U.S. Geological Survey, Bugwood.org
Kudzu often grows over, smothers and kills all other vegetation, including trees. Preferred habitat includes open, disturbed areas such as roadsides, right-of-ways, forest edges and old fields.
Kudzu is a deciduous, climbing vine capable of reaching lengths of over 100 feet. Flowering occurs in midsummer, when 0.5 inch long, purple, fragrant flowers hang, in clusters, in the axils of the leaves. Kudzu is native to Asia and was first introduced into the United States in 1876 at the Philadelphia Centennial Exposition. It was widely planted throughout the eastern United States in an attempt to control erosion.
Fabales > Fabaceae > Albizia julibrissin Durazz.
James H. Miller, USDA Forest Service, Bugwood.org
Mimosa invades any type of disturbed habitat. It is commonly found in old fields, stream banks, and roadsides. Once established, mimosa is difficult to remove due to the long lived seeds and its ability to re-sprout vigorously.
Mimosa is a small tree, 10 to 50 feet in height, often having multiple trunks. It has delicate-looking leaves that resemble ferns. Flowering occurs in early summer, when very showy, fragrant, pink flowers develop in groups at the ends of the branches. Fruit are flat, 6 inch long seed pods that develop in the late summer. Mimosa is native to Asia and was first introduced into the U.S. in 1745. It has been widely used as an ornamental.
Feral Hog or Wild Boar
Sus scrofa Linnaeus
Feral hogs are domestic hogs that either escaped or were released for hunting purposes. They were first introduced into Texas by the explorer Hernando de Soto in the mid-1500's. However, it was not until the 1980's that populations of feral swine literally exploded across the state. There are approximately 2 million feral hogs in Texas. They cause an estimated $52 million of damage to Texas agricultural enterprises each year. Feral hogs also have a tremendous intrinsic rate of increase. Mature sows can have two litters per year and their female offspring can produce a litter of their own before their first birthday! As the hog reproduces, each generation loses more of their domestic characteristics and develops the traits needed for survival in the wild.
A mature feral hog may reach a shoulder height of 36 inches and weigh from 100 to over 400 pounds. Hogs have four continuously growing tusks (two on top, two on bottom) and their contact causes a continuous sharpening of the lower tusks. They have relatively poor eyesight but have keen senses of hearing and smell. Feral hogs cause damage to crops and habitats and compete with wildlife and livestock.
Nutria is a large, semi-aquatic rodent with a long, round tail. It has webbed hind feet and looks like a beaver without the large flat tail. Nutria are found from Central Texas eastward and on the Texas Coast in marshes, swamps, ponds and lakes. They can cause damage by burrowing into levees, dikes, and embankments, which can lead to erosion, road damage and more. Nutria also eat aquatic vegetation, which can lead to erosion and loss of habitat for other species.
Nutria was introduced around the world, primarily for fur farming. Nutria fur farms in the United States originated as early as 1899. They were initially imported to California, Oregon, Washington, Michigan, New Mexico, Louisiana, Ohio, and Utah for the fur farming industry. Various government agencies subsequently transported nutria to Alabama, Arkansas, Georgia, Kentucky, Maryland, Mississippi, Oklahoma, and Texas with the intent of using the species to control unwanted vegetation. Nutria breed year round and are extremely prolific. The number of young in a litter will average 4-5, and females can breed again within a day of having a litter.
Red Imported Fire Ant
Solenopsis invicta Buren
The red imported fire ant was introduced around the 1930's and has spread to infest more than 260 million acres of land in nine southeastern states. This species has become very abundant, often displacing native ant species. The average colony contains 100,000 to 500,000 workers and up to several hundred winged forms and queens. In areas with multiple queen colonies, there may be 200 or more mounds and 40 million ants per acre.
The red imported fire ant builds mounds in almost any type of soil, but prefers open, sunny areas such as pastures, parks, lawns, meadows and cultivated fields.
Thousands of fire ants live in each mound. If a mound is disturbed in any way, hundreds of ants rush out in seconds, climb on whatever disturbs them, including humans, and begin stinging. Each ant hangs on with its mandibles and can sting many times. Stings immediately burn like fire (hence the name “fire ant”). An estimated 14 million people are stung annually.
This site last updated on
April 27, 2010