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When a Species is Endangered

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Published on: Jul. 2, 1999

Last revision: Nov. 3, 2010

It is one thing to track the kinds of plants and animals living in Missouri, but quite another to collect enough information to know how every individual species is doing--to track the health of our living resources. Fortunately there are professional biologists and resource managers to assist with the task.

The process of designating endangered species is more rigorous than many people guess. It is as factual as existing data allows and is scrutinized by people who know the species well and can make an informed assessment.

How many places a species lives is a fact, and biologists try to keep as accurate a count as possible. How many of these remaining populations of animals or plants are capable of surviving into the future is professional judgement. How long threatened populations will persist is prediction. Biologists and managers are asked to predict if the remaining populations are likely to disappear in the near future. This is not science at all, but prognostication. Endangered or not, it's hard to say.

Robins and white oak trees are doing well. Clearly they are not endangered.

Greater prairie-chickens and western prairie fringed orchids are not doing well. They are endangered.

How do we know? Conservation Department biologists assess the current condition of the species, compare it to the historic condition, evaluate present threats and recommend a status.

Prairie-Chickens

Greater prairie-chicken numbers, for example, have never been lower in Missouri, at least not in recorded history. And the population monitoring record is good. Conservationists reported approximately 12,500 birds in the state in 1907, and hunting was stopped. Populations have fluctuated through the years, and the current population is estimated at 1,000 to 3,000 resident birds.

Prairie-chickens are declining in Missouri. Their population trend is best represented by annual counts made along 13 routes that cover 236 square miles. In the spring of 1997, we counted only 214 displaying males, suggesting that prairie-chicken numbers continue on a long-term downtrend that began in the late 1960s. If the trend set over the past 30 years continues, our resident birds will disappear from Missouri by the year 2009.

There continue to be threats to the birds that remain in Missouri. Overgrazing, late hay mowing and poorly timed burning reduce the amount of cover available for nesting and roosting. Lack of large blocks of grassland habitat also limits them. The same habitat problems that affect other grassland birds, such as quail, have caused prairie-chicken numbers to decline. Along with habitat loss, wet spring weather has reduced brood success and increased predation associated with our modern fragmented landscape. The outlook for prairie-chickens is indeed poor.

How many prairie-chickens lived in Missouri historically? No one can say for certain, but surely prairie-chickens numbered in the hundreds of thousands. The prairie-chicken formerly existed in every prairie county of Missouri, and additional populations were scattered throughout the grassy ridges of the Ozarks. What we see today is easily less than one percent of the number that once lived here. This native bird is endangered.

Orchids

Western prairie fringed orchid numbers have never been lower in Missouri. Unlike prairie-chickens, however, there is almost no population monitoring history to work from. We know of only three remaining populations in Missouri. All persist on small remnant tallgrass prairies in north Missouri. As best we can determine, there are fewer than 100 plants at these three sites. There are probably seeds hidden in the seed bank, but how many and how long they will remain viable is anyone's guess.

How many prairie fringed orchids lived in Missouri historically? We have a good indication of their range because records confirm this species grew as far north as the Iowa border and as far south as the Springfield area. Within this range they probably were scattered and sometimes locally abundant. A botanist in Jackson County indicated that this species was "generally uncommon" in the early 1900s.

The current populations are probably stable, but population monitoring has been conducted for only a few years--too short a time to indicate a trend. Threats are minimal to two of the remaining populations because they are managed on public land. The third, on private property, has a reasonable level of security through cooperative management with the landowner.

Rangewide, this species is threatened by habitat loss, overgrazing, poorly timed hay mowing, wetland draining and improper use of pesticides. Pollination by large sphinx moths is an essential part of their life history, but it is uncertain whether there are enough plants at any of these sites to attract pollinators. There are few remaining plants in Missouri. Restoration of sufficient habitat and the knowledge and public support to reintroduce this species back to these habitats seems unlikely.

Fewer than one percent of the potential prairie habitat remains, and though two sites are protected, the remaining population is small and vulnerable. This native plant is endangered.

Listing Generates Monitoring

Endangered is an unfortunate condition. Addition to the endangered species list means that the remaining populations of that species are badly in need of conservation. Listing generates additional monitoring from Conservation Department researchers, stimulates public education, offers better publicity and may result in additional land protection.

Defining our Terms

Some people insist that we list species earlier so that we have more lead time, more options. Conservation Department biologists, hesitant to use the category endangered unless a species is near extinction, assign other categories of concern. Some species are listed as threatened. Others are rare. Others are uncommon. This is how biologists share their concern about fish, wildlife and plants that are not doing well in Missouri.

If a plant or animal is gone from Missouri, but still lives somewhere else on earth, we consider that species extirpated from Missouri. If a species of plant or animal is gone from Missouri, and no longer exists anywhere else on earth, we label it extinct.

The standards are high and it is difficult to get on the list of endangered species. The endangered species list is not a good list to be on, but it is a necessary list.

Unfortunately for many species, endangered species status--a designation that should generate a response for recovery actions--arrives so late that extraordinary efforts are necessary to prevent extinction. Are we too late for prairie-chickens and prairie fringed orchids?

We were not too late for the bald eagle. Eagle populations declined from low to almost extinct in the 1960s. By the 1970s there were no eagles nesting in Missouri at all. Because of public concern, legal protection and reintroduction efforts, bald eagles have increased to the point that their status has been changed from endangered to threatened. For many plants and animals, endangered species listing was a call for action, and it set the stage for recovery.

COUNTING an Endangered Milkweed

Mead's milkweed is a federally threatened plant. This milkweed is not as robust as the common milkweeds that we see growing along roadsides. It is smaller and more difficult to detect. And this species has not adapted to changes in the land. It does not accept disturbance as readily as more common milkweeds. Remaining populations of Mead's milkweed are few indeed, restricted to remnant prairies or rhyolite glades in the Ozarks.

Even on protected areas, Mead's milkweed is not abundant and, despite our efforts, its numbers continue to decline. A Conservation Department botanist, along with a crew of volunteers, visits one of the largest populations every June to walk the prairie and count milkweed plants. He returns later in the year to count fruit pods to evaluate how many plants are successfully producing seeds.

Efforts like these provide some measure of the current condition of endangered plants like Meads milkweed.

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