D e s e r t E x p o s u r e
April
2008
bats
Page: 2Marikay Ramsey says her work with bats in the Black Range and eastern side of the Gila National Forest has been particularly rich — due to a concentration of resident species and the area's location being key to migrating bats. "We're the most diverse part of the US," she says. "In addition to our resident species, we have tropical and subtropical species passing through as well."
Of the 35 species of bats native to the western US, 28 dwell in the southwest between New Mexico and Arizona. Variety of terrain, Ramsey says, is what makes the southwestern part of New Mexico so attractive to the night-flying mammals.
"We have a lot to offer bats, an extremely diverse range of habitat," Ramsey says. "We have conifer forests, we have open areas, and we have caves. And of course our mines — they love those."
Abandoned underground mines provide significant habitat for bats. More than half the species of bats in North America are known to use mines, and at least 22 of the 35 species in the West use abandoned mines to some extent. Mines provide an alternative roosting option and help offset natural habitat loss and human disturbance of bat colonies in caves. Abandoned mines become bats' winter and summer roosting areas, day-roosting spots, maternity sites for reproducing bats, shelter from predators, and feeding and watering sites.
Ramsey says loss of habitat — the loss of large conifers, closing abandoned mines and removing old bridges under which bat colonies often roost, to name a few — has been the number-one threat to bats.
"A lot of mines are being closed for public safety," she says. "What we (scientists) have to do is to say, 'Wait! We need to make sure it is not a really important roost for bats.' And that's not always an easy thing to determine. Bats use mines in very different ways, maybe only certain times of year or certain parts of the mine that you can't even view.
"There are different ways of going about it. You can determine bat presence by piles of guano — that's their waste," she explains. "There can be significant accumulations of it. Other times, more frequently, you find a mine with just a spattering of guano. Sometimes we find insect parts — like legs and wings — that the bats don't eat. Those are left behind and alert us that bats are eating there. Those are really good clues to determining what kind of species are coming through and how often they occupy the mine or cave."
But absence of insect parts and bat waste doesn't mean bats are not using a mine for their roost.
"A tricky thing is that bats hibernate," Ramsey says. "When they are hibernating, they're also not eating, not defecating, so it gets tricky to know they are there. Then the scientists are just left with their best judgment. I always try to err on the side of caution for the bats, assuming if there is some evidence of their presence that they are there in some quantity."
Some conservation groups, she notes, like the WBWG and the New Mexico Bat Working Group, fight for legislation to preserve mine habitat for bats. "It's a balance of public safety and bat habitat," she says. "Of course, the companies don't want the liability of having an unsafe open mine, a hazard to humans. But one thing we can do is instead of them just back-filling a mine and shutting it off, we can get a bat gate installed."
Placing a gate of horizontal bars over a culvert is a popular solution, she says, as it is simple to install, low cost and keeps humans out while allowing bats to pass in and out.
"I've been working with Arizona fish and game, trying to get a particular mine gated for bats," she says. "It gets tricky, as it is a designated wilderness area. It's also a particularly important piece of habitat, as it's geothermally heated, so certain species live there that don't live everywhere else."
Ramsey acknowledges that cost often enters into the picture. "If the mine opening is next to a trail head or something like that, near the public, then there has to be some more sophisticated gate systems. Sometimes that involves concrete and such, and of course, that's more costly. We're mostly talking about abandoned mines, so they are owned by land management agencies and there's not a lot of money for that kind of thing. We (conservation groups) try to get grants. Fish and game and state agencies may help with the grant process."
In 1993, Bat Conservation International (BCI) and the Bureau of Land Management (BLM) founded the Bats and Mines Project, with a goal of reducing the loss of bats during closures of abandoned mines. Many states now are recognizing the importance of mines as bat habitat and are incorporating the abandoned mines issue into their wildlife and bat conservation plans. BCI says that bat-friendly gates are gaining in popularity.
Another threat to bat survival, Ramsey says, is wind energy. "We will be getting some wind energy sites — one in the Burros and one at the southern end of the Black Range. There are lots of bat and bird deaths from those turbines," she says. "We're all yelling for green energy methods, but there's a cost to bats and birds. These issues need to be addressed."
Still another emerging threat is a deadly one about which little yet is known. "Recently, scientists and other people concerned about bats have been talking about White Nose Syndrome," Ramsey says. "No one knows yet what it is, what's going on with that. There were a few thousand deaths from it last year in the Northeast. It's characterized by a ring of fungus around the nose, but that appears to be just a symptom, not a cause. Hibernating bats eat a lot to build up fat reserves, but in the bats with White Nose Syndrome, their fat deposits are inadequate. The first thing that enters scientists' minds, of course, is climate change. Are warmer temperatures causing this? Are bats the canaries in the coal mine, warning us that something bad is happening and it's coming our way?
"We haven't seen any White Nose Syndrome here in the Southwest, but we are looking out for it." Ramsey, also a member of the NMBWG, has made flyers to bring awareness about this disease to spelunkers and cave enthusiasts.
| A Face Only A Mother Could Love? Who says bats aren't lovable? You can "Adopt-a-Bat" for just $15 by clicking a link on Bat Conservation International's Web site, www.batcon.org The seven available species pictured offer a fun and friendly introduction to the world of bats. Adoptive "parents" receive:
Adopt a bat for $15 or pay $35 for adoption with a basic level membership in the organization. |
On the bright side, indiscriminant killing of bats is not the threat it once was, Ramsey says. "We do, unfortunately, see some of that. We do occasionally find some bat carcasses. But thankfully, kids these days have less prejudices and fears, and they educate the grown-ups in their families, too."
Art Telles, the US Forest Service wildlife and fish program manager who works out of the Silver City office, echoes the importance of educational outreach, yet also acknowledges that budget cuts have left an unfortunate gap in this regard. "We lost a lot of our information specialists," Telles says. "Locally, we really count on things like the Aldo Leopold High School, because they're environmentally aware, and the GCEC (Gila Conservation Education Center) trunks going out to local science teachers to help fill the gap." (See the November 2006 Desert Exposure.)
"A biologist's job through the forest service is to make sure endangered or sensitive species are not being threatened or negatively impacted," Telles adds. "We make sure that any projects in the forest do not push them into a threatened status." Such projects might include grazing allotments, fuel wood gathering, prescribed burns and putting in power lines.