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3/3/2010

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Going, going ...
Is the Orlando cave crayfish already gone?

 

Ever seen an Orlando cave crayfish?

Only a few biologists, some cave divers and the occasional well driller have. That’s about it. But it’s down there, perhaps under your feet right now.

How many there are, and how they’re doing, however, is tough to determine. What is known is that it’s one of 15 species of cave crayfish unique to Florida. Procambarus acherontis, as it’s officially known, has only surfaced at a few locations in northern Orange and southern Seminole counties. It’s also called the Orange-Seminole cave crayfish, according to Dick Franz, a researcher at the Florida Museum of Natural History in Gainesville.

“We prefer the use of the name ‘Orlando cave crayfish’ because the entire world distribution occurs within the Orlando metropolitan area,” Franz says. “It brings into focus the precarious conservation status of this species in one of the most rapidly expanding urban areas in Florida.”

Franz has probably written more about the Orlando cave crayfish than just about anyone, especially in 1994’s “Review of Biologically Significant Caves and their Faunas in Florida and South Georgia,” an article in the journal Brimleyana.

The creature is found in the flooded limestone caves along the Wekiva River, but it’s only been officially catalogued by biologists a few times. The first, when it was recognized as a unique species, was when Einar Lonnberg pulled some out of a hand-dug farm well near Lake Brantley in 1894, according to Franz’s article.

“This site is now located on a portion of the Sabal Point Golf Course. The owners and groundspeople at the golf course knew of no open wells on the property, and we presume the well has been filled,” Franz wrote.

They turned up in the Palm Springs basin in Seminole County in 1938, 1964, 1965 and 1975. One came out of a county well at Long Lake in 1982, and another specimen was collected in 1990. And that’s about it.

Individual crayfish probably don’t range much more than about 150 feet from home base, according to the NatureServe Species Profile database of research.

The Orlando cave crayfish is described there as “critically imperiled,” limited to a small area and squeezed by rapidly expanding human population. One of five known locations near Orlando – a sand-walled sinkhole – collapsed, leaving just four nearby windows on the crayfish’s habitat.

Three of those are in or near Apopka. One is surrounded by ramshackle houses and just a half-mile from major strip malls, but the others are sheltered by Kelly Park and Wekiwa Springs State Park.

Those wells and springs, however, are only peepholes into a drowned world of small, interconnecting, lightless caves below the water table. Down there, in the crevices underlying a broad swath of central Florida, the Orlando cave crayfish and its cousins live wherever they can fit, according to Paul Moler, research biologist for the Florida Fish and Wildlife Conservation Commission in Gainesville.

“Divers see them regularly when they go into those springs,” he says. “The caves that feed the springs are fairly extensive.” Well drillers suck up a handful now and then too, Moler says.

So what’s the problem? If they’re down there and we’re up here, why worry? Because human impact isn’t just on the surface. The big question mark for the Orlando cave crayfish and its dark-adapted neighbors is whether they’re seriously impacted by groundwater pollution, especially nitrogen and phosphorous.

“The nutrients are coming from septic tanks, fertilizer, dairies,” Moler says.

Researchers know those are in the groundwater, but aren’t sure how much damage they do inside the caves. When the water flows into sunlight, however, the nutrients feed huge blooms of algae that take over from existing plant life. “A lot of the springs now are just carpeted with algal mats,” Moler says.

According to the U.S. Environmental Protection Agency, about two-thirds of the Florida waters listed as “polluted” are so designated because of nitrogen and phosphorous from urban stormwater runoff, water treatment plants, air pollution, livestock and crop fertilizers – all of which can be found a few yards above the home of the Orlando cave crayfish. Since water actively flows through the cave network, even pollutants far upstream can harm cave animals, the EPA says.

Responsibility for keeping groundwater clean enough for people and crayfish alike falls on local water management districts and the state Department of Environmental Protection.

“The crayfish is not their primary concern in doing so, but it’s not as though nobody’s looking at the water quality, and quantity, for that matter,” Moler says.

And now, for the first time, the feds are stepping in to mandate specific controls on groundwater nutrient levels. The federal decision to intervene came in late 2008 when the EPA, prodded by several environmental groups, decided that state standards weren’t doing enough. So in late 2009, the EPA proposed a set of numeric standards for Florida groundwater, set for a final decision by October 2010.

“They’re specifically for nitrogen and phosphorous,” says Davina Marraccini, EPA media specialist in Atlanta.

The numeric standards apply specifically to inland waters like lakes and springs, but similar rules for coastal waters are to be set in the following year.

The state, however, isn’t ready to accept that. The Florida Department of Environmental Protection plans to reply to the EPA’s proposed standards and has already come out with a list of criticisms, according to DEP spokesperson Dee Ann Miller. The state is worried that many streams deemed “healthy and preserved streams” also don’t meet the proposed standard, she says.

The posted list of state disagreements says the EPA’s measurements are inaccurate, and that its requirements are unrealistic and would be more expensive than claimed. But not all of the protest aims at softening the standard: DEP does argue that the proposed criteria for nitrates and nitrites wouldn’t be protective enough.

So apart from the general importance of water quality, why bother about a funny-looking kind of crayfish anyway?

“The answer to that is really dependent on who asks the question,” Moler says.

For believers in a deity, there’s the responsibility of stewardship over creation; but for the science-minded, there are lots of reasons stemming from ecology and evolutionary biology, he says. In short, the Orlando cave crayfish deserves as much attention as other, more visible links in the chain of life; because when it’s gone, it’s gone.

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