Endangered Isn't Forever

By Craig Ten Brink | December 2, 2002
From Missouri Conservationist: Dec 2002

We hear so much about extinction and endangered species today that sometimes the problem seems hopeless. If we take a close look at what is being done to protect some species, however, we see that, unlike extinction, endangered doesn't have to be forever.

Perhaps the most famous example of species recovery is the bald eagle. The bald eagle became endangered across most of this country because of habitat loss, poisoning and pesticides, especially DDT which caused birds to lay eggs with shells so thin that they often broke before the young could hatch.

DDT has been banned in the United States, and it is illegal to harm bald eagles. With the help of reintroduction programs, the bald eagle has made a comeback across the country, and nowhere has its recovery been more remarkable than in Missouri. Not only do thousands of eagles spend the winter in Missouri, but an increasing number nest along Missouri lakes and rivers. In 1984, no eagles were known to nest in Missouri, but in 2001 as many as 116 eagles were raised from 59 different nests in the state.

In 1995, the U.S. Fish and Wildlife Service changed the federal status of the bald eagle from endangered to threatened. In 2000, the agency was on the verge of removing it from the threatened list.

Although bald eagles remain on Missouri's endangered list, all indications are that populations will continue to increase in coming years. Certainly the recovery of the bald eagle so far can be considered an endangered species success story. The bald eagle is a symbol not only for our country, but for the potential of endangered species recovery.

Some less visible species also are making comebacks. At one time, there may have been as many as 2 million gray bats in Missouri, but by the 1970s their population shrank to about half a million. Gray bats, which were listed as federally endangered in 1976, roost in caves year round. In winter, they gather in large groups to hibernate. Most gray bats in Missouri hibernate in the same three caves every winter, but this dependence on these specific sites has made gray bats vulnerable to disturbance by humans.

When hibernating, bats depend on stored energy to get through the winter. If they are disturbed during hibernation, they may use up valuable energy and starve before spring. Disturbance of maternity caves in the summer can cause bats to abandon caves, and can result in the death of young bats. Because gray bats congregate in large groups, a single disturbance can have a big impact on their population.

More gray bat caves now are protected, and populations in the state are rebounding. Some bat caves are protected by gates built at the entrance that allow bats to fly in and out, but keep people out. Smittle Cave in Wright County is a good example of the positive effects of cave gating. Smittle Cave was historically a maternity cave for gray bats until it was developed for commercial use. In 1985, the cave was bought and gated by the Conservation Department and now serves as a maternity cave for more than 50,000 gray bats.

Thanks to continued protection, we can be optimistic about the future of gray bats in Missouri.

Recovery efforts are also under way for the pallid sturgeon, a big river fish found mostly in the Missouri River and in the Mississippi River south of St. Louis. The sturgeon has changed little since the age of dinosaurs and can grow up to 6 feet long and weigh as much as 80 pounds. Although never plentiful, the pallid sturgeon population has been greatly reduced because of dam building, river channelization and pollution. It was listed as federally endangered in 1990.

The rivers where pallid sturgeon live are much altered from presettlement days, but by the early 1990s, pollution had been reduced to the point that fisheries biologists believed it was safe to release hatchery-produced pallid sturgeons back into the wild. In 1992, the Conservation Department successfully spawned pallid sturgeons at Blind Pony Hatchery, and in 1994, the Department released 7,200, two-year-old, pallid sturgeons into the Missouri and Mississippi rivers. All of the released fish were marked with tags printed with a telephone number to call if the fish were caught. Despite the large number of fish released, biologists believed the chances of recapture were slim.

Biologists were surprised, however, when a tagged fish was reported just a few months after release. Since then, more than 150 have been captured. In 1997, the Department released an additional 3,400 pallid sturgeons. Because sturgeon mature slowly, and females don't spawn until about 14 years of age, it will take some time to determine whether the released fish are reproducing. While stocking will continue for another 10 years, these efforts alone will not restore pallid sturgeon populations. Habitat enhancement projects are being designed that will likely enhance pallid sturgeon populations in the future.

Peregrine falcons have the distinction of being the only species in Missouri to be officially "delisted," and river otters are once again part of Missouri's landscape after a long absence. Missouri bladderpod also is making a comeback, helped in large part by private landowners. The Conservation Department is working with the USFWS to formally change its status from endangered to threatened.

Despite the success stories, many other species are still in trouble. the Tumbling Creek cavesnail, which is found in only one cave in Missouri and nowhere else in the world, was recently "emergency listed" as endangered. Curtis' pearly mussel is close to extinction, and Indiana bats continue to decline despite efforts to protect them. Blanding's turtles and Illinois chorus frogs also are in trouble.

Geocarpon, a tiny plant found on sandstone glades, and running buffalo clover are in danger. Red wolves, small whorled pogonias, and red-cockaded woodpeckers disappeared from the Missouri landscape before anything could be done to try to save them. The eastern prairie fringed orchid is now considered extirpated in Missouri, but small populations exist in a few states to our east.

We are constantly learning more about how to save endangered species, and how to keep species from becoming endangered in the first place. We hope our successes will serve as reminders that just because a species is endangered, it doesn't have to stay that way.

This Issue's Staff

Editor - Tom Cwynar
Managing Editor - Bryan Hendricks
Art Editor - Dickson Stauffer
Artist - Dave Besenger
Artist - Mark Raithel
Photographer - Jim Rathert
Photographer - Cliff White
Staff Writer - Jim Low
Staff Writer - Joan McKee
Circulation - Laura Scheuler