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Alabama's Wildlife Habitat is Being Invaded

MONDAY, 19 APRIL 2010


Alabama's physiographical regions vary from the Coastal Plains north to the Cumberland Plateau. These different regions provide a vast diversity of wildlife habitat. Many of these habitats have been invaded by nonnative plant species that have displaced native wildlife food sources. These invasive species range from trees to forbs and affect each physiographical region differently.

There is only one species of tree that is recognized by the Alabama Invasive Plant Council (ALIPC) to have extensive infestations in Alabama. The Chinese tallow tree, commonly called popcorn tree, was introduced as an ornamental in the 1700s due to its attractive fall foliage. It produces a lot of seed that is used by birds as a food source and as a result, the seeds are deposited elsewhere. In drainage areas, the seed are transported by water, which results in heavy infestations along the stream banks. Tallow trees can be controlled by multiple herbicide applications.

Three shrubs are invading wildlife habitats. The thorny olive has been sold as a supplemental food source for wildlife. It is typically planted in wildlife openings where it creates localized infestations. ALIPC lists it as a category two species, which produces scattered and localized infestations. Birds heavily seek the fruit of the thorny olive as a food source. The fruit is digested by the birds, leaving a scarified seed. When this seed is defecated by the birds in other locations, starts additional infestations. Multiple herbicide applications are used to control the rate of spread.

Both Chinese privet and multiflora rose have a spot in Alabama's top 10 invasive weeds. They both form heavy infestations and create problems for wildlife managers. Privet spreads by birds eating the seeds and by root sprouts. Birds aid in starting new infestations whereas root sprouts help already established infestations to get bigger. Multiflora rose creates a dense thicket that nothing can enter. Herbicide treatments are the best means of control for both species.

Kudzu and Japanese climbing fern have also made the ranks of Alabama's top 10 invasive plants. Japanese climbing fern’s spores are spread by both wind and water. Prescribed burns as well as multiple herbicide applications can control this species. Kudzu is well known throughout the south. It spreads along rights of way, power lines and fencerows. It covers anything and everything that gets in its way. Control methods may include over grazing, herbicides, or simply pulling up its rootstocks.

Cogongrass is the only species of grass that really stands out. It too, is one of Alabama's top 10. This species could easily hold the number one spot as the worst invasive in Alabama. It forms circular patches that spread in two ways. Each patch can spread outward by its rhizomes (roots). The rhizomes have a sharp point that is used to penetrate the rootstock of already established plants. Once above ground, the foliage shades out all of its competition creating nothing but cogongrass on the forest floor. Each seed head produces approximately 200 wind-born seeds that may be dispersed up to 100 feet. In high winds, the dispersal distance may be further. Cogongrass is particularly bad for wildlife habitat because not only does it out compete native vegetation, but it also creates a fire hazard. This species is very flammable and burns at very high temperatures that will consume not only the litter, but the duff layer as well. The duff layer is a layer of decomposing vegetation that is just above the soil. Cogongrass also rebounds very well after a fire. This species can be controlled by herbicide treatments before flowering in March and April and another treatment during September before it goes dormant. These treatments will need to be repeated every year for as long as the grass is still appearing. It can also be controlled by a combination of herbicide treatments and disking. Treating cogongrass as a young patch is easier so don't wait.

The above-mentioned species are only a handful of invasive species in Alabama. Many more affect aquatic habitats, rights of way, pastures, urban areas, and even well managed forest. A full list of invasive species in Alabama can be found on ALIPC’s Web site, www.se-eppc.org/alabama, along with other useful information. Another helpful resource is the USDA-Forest Service General Technical Report SRS-62 "Nonnative Invasive Plants of Southern Forests" by Dr. James H. Miller. This guide is very useful in identifying invasive species. It also lists recommended herbicide treatments for each species.

The Alabama Department of Conservation and Natural Resources promotes wise stewardship, management and enjoyment of Alabama’s natural resources through five divisions: Marine Police, Marine Resources, State Lands, State Parks, and Wildlife and Freshwater Fisheries. To learn more about ADCNR visit www.outdooralabama.com.

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