FacebookTwitterGoogle+RedditEmail

Wolverines on the Brink

by GEORGE WUERTHNER

I attended the Fish and Wildlife Service’s recent wolverine listing hearings in Helena, Montana.  Opponents, including a number of Montana state legislators as well as MDFWP, argued that wolverine populations were “stable” or even “increasing” and therefore did not warrant listing under the Endangered Species Act.

While the ill-informed state legislators who testified could be forgiven for not understanding basic biology, MDFWP does not have that excuse. Their opposition to listing of the wolverine and their insistence on continued trapping when the state’s wolverine population is so tiny is both ecologically irresponsible and a breach of the public trust to protect Montana’s wildlife heritage.

The most obvious long-term threat to the wolverine is climate change. That will become a greater threat to wolverine in the future. However, what is ignored by many opponents of listing is that with a population of only 250-300 animals in the entire lower 48 states, and perhaps no more than 175 in Montana, wolverine are already well under what most conservation biologists believe is a minimum number for long-term survival. In other words from a purely biological perspective they are clearly endangered with extinction now, regardless of what happens with global climate change in the future.

Wolverine have one of the lowest reproductive rates of any of the West’s mammals. Even in the best of circumstances, wolverine can barely balance their population increases against losses. Any increase in mortality, for whatever reason, could cause such a small population to spiral downward to extinction.

In addition, its breeding behavior makes the wolverine more prone to extirpation than other animals. Wolverine males will stake out a territory that over lapses with a number of females. This automatically ensures lower genetic diversity because the one male may breed several females.

With only 250-300 animals, due to this behavioral trait the “effective breeding population” is only 30-40 animals. This tiny reproductive effort almost guarantees a loss in genetic diversity and indeed, recent genetic studies have confirmed that wolverine in the lower 48 states suffer from low genetic diversity compared to wolverine in more robust populations in Canada.

Wolverine. Photo: US Fish and Wildlife Service

Wolverine. Photo: US Fish and Wildlife Service

Loss of genetic diversity can lead to all kinds of genetic disorders that can threaten the species survival, and also limits its ability to cope with random stochastic events that individuals with greater genetic diversity might be able to cope with. As a rule of thumb, most geneticists believe that an effective breeding population of at least 500 individuals is needed to ensure the long term survival of carnivore species. With only 35-40 breeding animals in any one year, wolverine are well below this safe threshold.

Worse for the wolverine’s long term survival, the remaining wolverine populations are frequently found in small isolated groups in widely scattered mountain ranges. The survival of the larger population is dependent on the health of these small populations. Trapping or any other increase in mortality could easily wipe out the animals from mountain range to mountain range by removal of just one or two individuals.

As the FWS notes: “Human-caused mortality of wolverines is likely additive to natural mortality due to the low reproductive rate and relatively long life expectancy of wolverines… This means that trapped populations likely live at densities that are lower than carrying capacity, and may need to be reinforced by recruits from untrapped populations to maintain population viability and persistence.”

Even though Montana’s wolverine trapping regulations are conservative, it can still be additive to overall wolverine losses. For instance, the trapping of one male may result in immigration of a new male into the territory. Male wolverine will often attempt to kill the young sired by other males, so it’s entirely possible that the loss of one male to a trapper, may in effect result in the loss of many more wolverine.

Similarly the trapping of a pregnant female or a female with young may result in the starvation of her kits, again creating a loss to the population. If this trapping mortality were to occur in one of the smaller sub populations, it could result in the local extirpation of that population.

As trustees responsible for preserving Montana’s wildlife heritage, MDFWP needs to use biology in formulating policies. And biology clearly warrants endangered listing status under the Endangered Species Act.

George Wuerthner is the Ecological Projects Director for the Foundation for Deep Ecology and has published 35 books, including soon to be released Energy: Overdevelopment and the Delusion of Endless Growth

 

 

George Wuerthner has published 36 books including Wildfire: A Century of Failed Forest Policy. He serves on the board of the Western Watersheds Project.

More articles by:
June 28, 2016
Jonathan Cook
The Neoliberal Prison: Brexit Hysteria and the Liberal Mind
Paul Street
Bernie, Bakken, and Electoral Delusion: Letting Rich Guys Ruin Iowa and the World
Anthony DiMaggio
Fatally Flawed: the Bi-Partisan Travesty of American Health Care Reform
Mike King
The “Free State of Jones” in Trump’s America: Freedom Beyond White Imagination
Antonis Vradis
Stop Shedding Tears for the EU Monster: Brexit, the View From the Peloponnese
Omar Kassem
The End of the Atlantic Project: Slamming the Brakes on the Neoliberal Order
Binoy Kampmark
Brexit and the Neoliberal Revolt Against Jeremy Corbyn
Ruth Hopkins
Save Bear Butte: Mecca of the Lakota
Celestino Gusmao
Time to End Impunity for Suharto’’s Crimes in Indonesia and Timor-Leste
Thomas Knapp
SCOTUS: Amply Serving Law Enforcement’s Interests versus Society’s
Manuel E. Yepe
Capitalism is the Opposite of Democracy
Winslow Myers
Up Against the Wall
Chris Ernesto
Bernie’s “Political Revolution” = Vote for Clinton and the Neocons
Stephanie Van Hook
The Time for Silence is Over
Ajamu Nangwaya
Toronto’s Bathhouse Raids: Racialized, Queer Solidarity and Police Violence
June 27, 2016
Robin Hahnel
Brexit: Establishment Freak Out
James Bradley
Omar’s Motive
Gregory Wilpert – Michael Hudson
How Western Military Interventions Shaped the Brexit Vote
Leonard Peltier
41 Years Since Jumping Bull (But 500 Years of Trauma)
Rev. William Alberts
Orlando: the Latest Victim of Radicalizing American Imperialism
Patrick Cockburn
Brexiteers Have Much in Common With Arab Spring Protesters
Franklin Lamb
How 100 Syrians, 200 Russians and 11 Dogs Out-Witted ISIS and Saved Palmyra
John Grant
Omar Mateen: The Answers are All Around Us
Dean Baker
In the Wake of Brexit Will the EU Finally Turn Away From Austerity?
Ralph Nader
The IRS and the Self-Minimization of Congressman Jason Chaffetz
Johan Galtung
Goodbye UK, Goodbye Great Britain: What Next?
Martha Pskowski
Detained in Dilley: Deportation and Asylum in Texas
Binoy Kampmark
Headaches of Empire: Brexit’s Effect on the United States
Dave Lindorff
Honest Election System Needed to Defeat Ruling Elite
Louisa Willcox
Delisting Grizzly Bears to Save the Endangered Species Act?
Jason Holland
The Tragedy of Nothing
Jeffrey St. Clair
Revolution Reconsidered: a Fragment (Guest Starring Bernard Sanders in the Role of Robespierre)
Weekend Edition
June 24, 2016
Friday - Sunday
John Pilger
A Blow for Peace and Democracy: Why the British Said No to Europe
Pepe Escobar
Goodbye to All That: Why the UK Left the EU
Michael Hudson
Revolts of the Debtors: From Socrates to Ibn Khaldun
Andrew Levine
Summer Spectaculars: Prelude to a Tea Party?
Kshama Sawant
Beyond Bernie: Still Not With Her
Mike Whitney
¡Basta Ya, Brussels! British Voters Reject EU Corporate Slavestate
Tariq Ali
Panic in the House: Brexit as Revolt Against the Political Establishment
Paul Street
Miranda, Obama, and Hamilton: an Orwellian Ménage à Trois for the Neoliberal Age
Ellen Brown
The War on Weed is Winding Down, But Will Monsanto Emerge the Winner?
Gary Leupp
Why God Created the Two-Party System
Conn Hallinan
Brexit Vote: a Very British Affair (But Spain May Rock the Continent)
Ruth Fowler
England, My England
Jeffrey St. Clair
Lines Written on the Occasion of Bernie Sanders’ Announcement of His Intention to Vote for Hillary Clinton
FacebookTwitterGoogle+RedditEmail