Welcome to the Universe: Interviews: Dave Armitage on North American Bat Deaths and Worldwide Extinction

Pavel Tkalitch: A hitherto unknown disease that has decimated bat populations
in several states across the US. Do you see evidence that this disease is
showing signs of spreading to the rest of the North American continent and
perhaps even beyond to other parts of the world?

Dave Armitage: I am not directly involved in the research surrounding the white
nose fungus, but from a paper published earlier this year in the journal
Science, it appears that the fungus is unable to grow very well at temperatures
higher than 10 degrees Celsius, which are temperatures bats generally only
experience during winter torpor in cave roosts. Therefore, I don’t think that
white nose fungus will be observed in warmer climates (like here in Florida).
However, I DID just receive an email alert regarding the first case of the
fungus in West Virginia, which is the most southerly incidence to date. Halting
the funguses’ spread from North America to caves in Northern Europe and Asia
should be a priority, and actions are already being taken by the caving
community to sterilize their gear upon entering and exiting caves.

Pavel Tkalitch: In your opinion, is the white fungus the ultimate cause of the
bat population decline, or is it merely a side effect where the fungus has
taken opportunity to prey on weakened or deseased animals?

Dave Armitage: Good question! This is probably the most active priority for bat
research and wildlife epidemiology in the U.S. today. It is currently unknown
what is actually killing the bats. What we do know is that this fungus is very
closely related to a common soil fungus found in cold climates that is
dispersed via birds and mammals, but does no harm to the host. Whether this
fungus is affecting the bats or is a symptom of a new virus or parasite is
still unknown, but whatever it is, it causes bats to awaken from torpor
(hibernation) and leave their winter roosts far too early. Once they emerge,
they cannot find insect prey and starve to death.

Pavel Tkalitch: Do you see any links between the white fungus that is affecting
bats, the fungus currently attacking amphibian populations or to the Colony
Collapse Disorder (CCD) that has been destroying large numbers of bees recently?

Dave Armitage: Unlike CCD or white nose, the mechanism by which chytrid fungus
kills frogs is known, and thus can be understood much better. One of the more
interesting and frightening hypotheses concering white nose in bats is that the
thawing of permafrost in Canada has freed this fungal species from the soil and
it has quickly adapted to growing on bats. The migratory and aggregatory
quality of the affected species is no coincidence, and it is likely transferred
between individuals from either direct contact or shared parasites. CCD is more
a product of many factors, the strongest in my opinion being a combination of
habitat loss and fragmentation, along with a switch to monocultures. Honeybees,
which are generalist pollinators, depend on a large number of plant species for
pollen. A switch to monoculture, combined with the inability to travel between
fragmented habitats has put local populations at a huge risk.

Pavel Tkalitch: Would you agree or disagree that Earth is currently in the
midst of a mass extinction event, the scale of which has been seen by our
planet perhaps only five times in the past?

Dave Armitage: Absolutely. While extinction is a natural process (99.9% of all
species that have ever lived are extinct), the rate at which species are
disappearing is not proportionate to paleontological (and even historical)
records. The difference between these big historical extinctions and the one
taking place now, though, is the lack of the ability for groups of organisms to
speciate (split into new species) after the disturbance event, since habitat
destruction and invasive species introductions can be thought of as processes
much more continuous than the "discrete" extinction events of times past.

Pavel Tkalitch: What is your opinion on the concept that species across North
America are dying out because they are unable to handle the changes
now sweeping through our environment?

Dave Armitage: Again, it is a fact that biodiversity on earth is being lost at
a tremendous rate, which is due entirely to anthropogenic impacts. To that end,
I believe that things ARE getting better. The environmentalist movement was all
but a joke until recent years (with the endorsement of celebrities and
politicians) and from the climate change and clean fuel initiatives, I think
more focus will be given to issues of biodiversity and habitat loss. I also
hope that the recent world economic downturn cuts down on the wastefulness of
the modern first-world consumer and curbs the exponential growth in population
that many countries are undergoing. Finally, I think that the real fostering of
an ecologically-conscious mind can best be done by instilling an appreciation
of nature on our children early in life by encouraging outdoors activities and
implementing environmental curricula within the educational system.

DAVE ARMITAGE ON NORTH AMERICAN BAT DEATHS AND WORLDWIDE EXTINCTION

WTTU is proud to present an interview with Dave Armitage, a research assistant specializing in
bat biology from the Department of Wildlife Ecology and Conservation at the University of Florida in
U.S. regarding a very unusual disease linked to large bat dieoffs across the Northeast in the United
States and how this dieoff is part of the current global mass extinction of species.

Dave Armitage has studied bat activity in the longleaf pine-wiregrass ecosystems of the
Southeastern U.S. As he says, historically, this highly-diverse ecosystem stretched continuously across
much of the Southeastern seaboard, but due to a number of factors, mostly stemming from habitat
loss and mismanagement, this unique habitat occupies less than 5% of its former coverage. This
system is entirely fire-dependent, and without frequent burns, hardwood shrubs (such as oak)
eventually out-compete the local plant community. This type of habitat is required by a number of
important species in the Southeastern U.S., including the gopher tortoise, Sherman’s fox squirrel,
Florida panther, Florida black bear, and the red-cockaded woodpecker.

Dave Armitage's project at the University of Florida is two-fold:
1) He is attempting to determine the linkages between prescribed fire and bat activity in the
longleaf pine-wiregrass ecosystem. Presumably the linkage is mediated by the effects of fire on
vegetative characteristics (tree density, understory structure) and the local insect community, which
interact to influence a bat’s choice of foraging habitat. To accomplish this, he is using a number of
remotely-operated bat detectors to record the animals’ ultrasonic echolocation calls as they pass near
the microphone. These vocalizations can be used as a measure of overall activity at a given sampling
location.
2) In a related project, he is building a library of bat calls from donated recordings and
recordings made from captured bats and applying machine learning classification algorithms to the calls
in order to come up with an objective method for determining the species of Southeastern bats
based on the characteristics of their echolocation calls. He hopes to expand on this project in the
years to come, the ultimate goal being to create an automatic vocalization system that can be
implemented in upcoming cellular telephone technology which will allow anybody to record a frog,
bird, or cricket and have that datum sent to a database containing the user’s exact GPS coordinates
where the animal was detected. This information is especially necessary to document species
abundances and changes in distribution over time.

In an email, I asked Dave Armitage some questions about the plight of the bats north of
Florida in New York, Vermont, Massachusetts, Pennsylvania, West Virginia, New Jersey, Connecticut,
and New Hampshire (see Linda Moulton Howe's research at http://www.earthfiles.com/news.php?
ID=1529&category=Environment), which have been dying in large numbers while hibernating in
their caves during winter over the past 3 years. A persistent symptom in this severe and
unprecedented population decline is a white fungus that rings the noses and faces of the sick and
dying bats while they hang in their caves, awaiting spring and the end of their winter sleep.
As Linda Moulton Howe says on her website Earthfiles.com, only four months ago in October
2008, lab analysis confirmed the white fungus is in the genus, Geomyces. That fungus loves cold
temperatures in the Arctic and apparently in Northeastern winter caves. However, no one had ever
heard of the fungus killing bats before now. The mortality rate is nearly 100% and there is nothing in
the global scientific literature about bats dying with white fungus rings around their noses (see photo
of a group of bats affected by the white nose fungus below).

The following is the interview transcript from 05/03/09 between myself - Pavel Tkalitch - and
Dave Armitage on the topic of North American bat deaths and the current global mass extinction of
species, only the sixth such event in Earth's history (see diagram below).

Home

Bats affected by the white nose fungus

Extinction events throughout Earth's history