Keep the Wild Alive - exotic species are threatening native wildlife - Brief Article

National Wildlife, June-July, 2001

Alien Invaders Threaten Many Imperiled Species

Experts from NWF's Keep the Wild Alive[ordinal indicator, feminine] and Backyard Wildlife Habitat[ordinal indicator, feminine] programs have urged federal officials to develop a strict plan to curb the invasion of exotic species that spread rapidly and choke out native wildlife.

Invasive species rank second only to habitat loss in causing the decline of threatened and endangered species, according to Rebecca Harrison, Keep the Wild Alive program coordinator.

Invasives have hastened the decline of a number of species highlighted in NWF's Keep the Wild Alive campaign:

* Feral goats introduced to Hawaii eat and trample rare Mauna Kea silversword plants; exotic Argentine ants attack bees and moths that pollinate the silversword.

* Introduced bullfrogs, bullhead catfish, bass, green sunfish and crayfish prey upon arroyo toads and their larvae and eggs.

* Leafy spurge, a rapidly spreading invasive shrub is choking out the western prairie fringed orchid in the Sheyenne National Grasslands of North Dakota and possibly in other areas; herbicides used to control spurge can kill the orchid as well.

* Rapidly spreading exotic plants fuel fires that destroy native vegetation on which the desert tortoise relies for food and shelter; ravens that follow human development into the desert prey on young tortoises.

* More than 200 foreign species of mollusks, such as the zebra mussel and Asian clam, are decimating native mollusks, including the dwarf wedgemussel.

Since a final control plan will be implemented gradually over several years, NWF is calling on the government to take immediate steps to prevent the introduction and further spread of exotic species.