Tuesday, December 30, 2014

Uncommon partnership for conservation: how rock climbers are leading the way for bat conservation

by Rob Schorr, CNHP zoologist

In North America, bats are declining at unprecedented rates.  Yet, the term “decline” does not do it justice.  For some reason, migratory tree bats have an affinity for wind turbine facilities, and dead migratory tree bats are being found at wind turbine sites throughout the US.  This unexplained attraction has led to an estimated 600,000 bat deaths annually in the US (Hayes, 2013).  This figure forces one to pause and contemplate a loss of this magnitude.  Unfortunately, this is not the most alarming figure from bat conservation over the last decade.  Since 2006 when a new disease, called White Nose Syndrome, made its way into North America hibernating bat populations have been decimated.  This disease is caused by a cold-loving fungus that infects tissues of hibernating bats, disrupting cellular function when the bats are unable to mount an immune response.  It is estimated that nearly 6 million bats have succumbed to the disease since its arrival in North America.  White Nose Syndrome can impact populations so dramatically as to kill 90-100% of the individuals once hibernating at a site (Frick et al, 2010).  For decades there has been mounting concern for bat populations as roosting locations are lost or disturbed, increased pesticide use alters their food resources, and native habitats are converted to other uses, but nothing prepared conservation biologists for this level of demise.

Fortunately for Colorado, mass mortalities at wind turbine facilities have not been seen, and, as far as we know, White Nose Syndrome has not made its way this far west.  Few biologists feel this is reason to let our guard down.  In fact, Colorado is faced with some challenges that would make diagnosing and abating mass die-offs harder than in eastern North America where White Nose Syndrome has been so impactful.  Colorado biologists have been unable to find hibernacula that house the number of bats seen in the East.  Eastern colonies can be in the millions or thousands, whereas Colorado colonies are substantially smaller and, possibly, more dispersed.  The question left for many conservation biologists is, “how will we know if Colorado bat populations undergo a decline?”

Biologist holding a little brown bat (Myotis lucifugus) captured in north-central Colorado.
Bat biologists in Colorado have a long history of systematically identifying and evaluating caves and mines as potential bat roosts.  Through ventures like the Bats-in-Inactive-Mines Project by Colorado Parks and Wildlife and numerous cave inventories much data have been collected on what underground structures provide bat habitat.  Yet, even with these survey efforts, few large hibernacula were uncovered.  So where are bats hibernating?

Based on research in Colorado, there is growing evidence that bats may be roosting in cracks and crevices.  Given the abundance of geological features in Colorado the number of potential roosts for bats is unfathomable, and there is little likelihood of biologists ever being able to systematically survey such a resource.  However, there is a recreational user group in Colorado that can help bat biologists with this problem.  Rock climbers in Colorado have shared numerous accounts of bats emerging from cracks and crevices during their climbing excursions.

Rob Schorr, Bernadette Kuhn, and Shawn Davis
On November 24th, bat biologists and rock climbers met to talk about how to develop a unique collaboration that might shed light on bat ecology and conservation in Colorado.  The brainchild of Rob Schorr and Bernadette Kuhn of Colorado Natural Heritage Program and Dr. Shawn Davis formerly of the Human Dimensions Department at Warner College of Natural Resources (now at Northern Michigan University), this project is bringing the two groups together to conserve bat populations.  

Shawn Davis leads bat biologists and rock climbers in
a discussion of the potential challenges and solutions to their partnership.
During their inaugural meeting, hosted as a World Café, the groups discussed how they could develop a mutually beneficial partnership that allow biologists to gain new information about bats’ use of crevices.  There was an overwhelming response that this collaboration could be fruitful and valuable for understanding bat resource use and, hopefully, bat conservation in advance of looming threats from White Nose Syndrome.

Karina Mullen Branson of ConverSketch documenting
the discussions and ideas in a mural format.

The final mural of the bat and climber café meeting.

Hayes, M. A.  2013. Bats killed in large numbers at United States wind energy facilities. BioScience 63:975979.
Frick, W. E., et al. 2010. An emerging disease causes regional population collapse of a common North American bat species. Science 329:679-682.

Wednesday, December 17, 2014

Hunter behavior: planning for the future of wildlife funding

by Rob Schorr, CNHP zoologist

As in Colorado, income from elk and deer hunting drives the economy of wildlife management in the state of Montana.  Rob Schorr and co-authors Dr. Paul Lukacs (University of Montana) and Justin Gude (Montana Fish Wildlife and Parks) analyzed Montana elk and deer hunter data from 2002-2011 to understand what factors influence hunter behavior and the funding that comes from license sales.

Rob Schorr elk hunting in Colorado
They determined that gender, residency, age, license price, and cohort behaviors influence retention and recruitment of individuals into the hunting population.   Millennial hunters grew in numbers but their recruitment decreased rapidly with age.  Baby Boomers were the largest contingency of the hunting population and had the highest retention rates, but as this group ages it is waning from the population.  Increases in license price decreased hunter retention and recruitment slightly.  Hunting populations were growing or stable until 2006, but hunting recruitment decreased by 50% from 2002 to 2011 leading to decreasing hunter populations in Montana.  The $50 million that comes from elk and deer hunting annually accounts for more than 60% of Montana Fish Wildlife Park’s revenue, but as hunter populations decline funding structures for management of game and non-game species will need to be altered.