The Pine Marten Transplants of Chichagof Island

When I think of the American Pine Marten (Martes americana), it invokes an image of giant, rotund spruces and hemlocks in an old growth forest. In my mind, the lithe body of a Pine Marten scurries around in the branches perhaps a hundred feet from the forest floor in search of a red squirrel or bird’s nest. A small squeak indicates that the small mustelid has connected with its prey. This vision could be considered “classic” in the fact that martens are strongly associated with mature, old growth forests (Greg 1995). In fact, their dependence on old growth forests is so strong that traditional logging methods have been cited as a driver of large scale declines of marten populations (Davies 1983). In some regions of Southeast Alaska marten are still abundant, and in general the Tongass National Forest offers great habitat for marten. However, they are most often found on the mainland, and I was told by a friend that they were introduced to Chichagof Island by people. That tidbit of information intrigued me, and as I dove into Pine Marten history on Chichagof I was very interested to find out a marten I crossed paths with is a descendant from a small introduction of intentional transplants.

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Transplanting wildlife to new areas in Alaska has been going on since the Russians began to settle  here (Paul 2009). Frequently transplants happened on the Aleutian Islands or the islands of Southeast Alaska and often the incentive revolved around economic opportunity. A well-known example of this is the transplant of Blue Fox to the Aleutians so they could be farmed and harvested for trapping.  The fox were responsible for extirpating several species of birds from the islands.  Over the years many species including Caribou, Sitka Blacktail, Mountain Goats and Elk have been introduced to new areas throughout Alaska. The first martens were introduced to Chichagof Island in 1949 to create a population for trapping (in fact Pine Martens are still Alaska’s largest fur market earning 1-2 million annually (Alaska Department of Fish and Game)). By 1954, 21 marten had been introduced to the Island and despite the low number of starting individuals, their numbers climbed rapidly in their new environment. It is estimated in 2006 over 2,200 marten were trapped on Chichagof Island. It’s a remarkably successful population here!

Blue Fox
It was fascinating to see this account from the early 1900s of Blue Fox farming. At the time it was implemented as a branch of the USDA. You can read the full text at : https://archive.org/details/bluefoxfarmingin1350ashb

Since transplants can have negative effects on resident populations, did the transplant of marten to Chichagof Island impact populations there? Anecdotally I have been told that Dusky Grouse (Dendragapus obscurus) numbers have declined on the island and that Northern Flying Squirrel (Glaucomys sabrinus) are not as abundant as they used to be.  Certainly each of these prey items are consumed by the martens. Buskirk (1983) found birds and squirrels made up a strong majority of the marten’s diet in Southcentral Alaska, but that voles, mice, and shrews were the most important items in the diet.  On Chichagof Island, the diet patterns are the same, although Ben-David et al. (1997) found high variation in the autumn and the presence of salmon and crab.  In the summer a marten’s diet may be made up 80% of birds and squirrels. Marten populations are normally not very large and hence would be unlikely to strongly influence prey, but Chichagof Island holds the highest abundance in the region (Flynn and Ben-David 2004). With these high populations and a diet favoring birds and squirrels, is it is possible that marten populations on Chichagof Island exert a top-down pressure on their prey? I believe based on the effect of being a successful transplant makes it it possible. However, I can find no data on the population trends of Dusky Grouse or Flying Squirrels on Chichagof Island and there are many other factors at play. For instance,  Dusky Grouse may find protection from predators in old growth  and flying squirrels are likely to benefit from old growth structure. Hence, removal of old growth by logging may lead to a reduced population. Rather than conjecture on a speculative answer, I will put it out there that a graduate student and the Alaska Department of Fish and Game could pair up on this venture.

I will leave you with a description of my encounter with an American Pine Marten. On October 16th, Hoonah received measurable snow before Fairbanks, Alaska.  The 14 inches of snow that lay on the ground was the first time Southeast Alaska had beat the Interior to snow in over 70 years. I started up my truck, my wife jumped in, and we headed out the road with the hope of photographing a bear in the snow. The lower elevations were slick and wet. 6 inches of slush lay heavy on the roads, but we made it the 10 miles to the turn towards False Bay. As we slowly climbed the pass the truck seemed to shrink into the ground as the snow levels rose. After only a couple of miles we were plowing snow with the bumper of the truck and it was evident that we would not go much further. The only catch was we could not find a place to turn around. On we drove hoping that our luck held out, when up the road we saw a small figure bound into the ditch. It plowed into a snow drift and then burst back out again. In a flash I was out with my camera clicking away. Pursing my lips I made small rodent sounds which intrigued the inquisitive creature. Turning its head rapidly it dove back into a snow bank and emerged a few feet away. To me it seemed as if the little fellow was simply enjoying the snow rather than doing anything too serious. He wove in and out of cover, posed for me and eventually bounded into the woods in search of greener (or whiter) pastures.

Pine Marten, American Pine Marten, Chichagof Island, Hoonah, Southeast Alaska, Martes americana
American Pine Marten on Chichagof Island near Hoonah, Alaska.

 

Cited:

R. Flynn and M. Ben-David. 2004. Abundance, prey availability and diets of American martens: implications for the design of old growth reserves in Southeast Alaska. U.S. Fish and Wildlife Service Grant final report. Alaska Department of Fish and Game.

Ben-David, M., Flynn R.W., Schell D.M. 1997. Annual and seasonal changes in diets of martens: evidence from stable isotope analysis. Oecologia. 111:280-291.

Buskirk, S.W. 1983. The Ecology of Marten in Southcentral Alaska. Doctoral Disertation. University of Alaska Fairbanks.

http://www.biokids.umich.edu/critters/Dendragapus_obscurus/

Davis, Mark H. “Post-release movements of introduced marten.” The Journal of Wildlife Management (1983): 59-66.

Drew, G. 1995. WINTER HABITAT SELECTION BY AMERICAN MARTEN (Martesamericana) IN NEWFOUNDLAND: WHY OLD GROWTH?. Dissertation.

Paul, T. 2009. Game transplants in Alaska. Technical bulletin #4. 2nd Edition.

Schoen, J., Flynn R., Clark B. American Marten. Southeast Alaska Conservation Assessment. Chapter 6.5

Ashbrook, F.G. Blue Fox Farming in Alaska. Accessed : https://archive.org/details/bluefoxfarmingin1350ashb 10/27/2016

https://www.fws.gov/refuge/Alaska_Maritime/what_we_do/conservation.html

 

Did You Just See A Proton Arc?

A proton arc is oftentimes described as a broad band of diffuse aurora. If you do a Google Image search for “Proton Arc” a plethora of beautiful images depicting a purple, red, green, or pale band of aurora will greet your eyes. Go ahead, really, search it, I can wait. Or, you can visit this website at Spaceweathergallery.com.

I had the pleasure of seeing this pale phenomenon in Juneau on September 20th, 2016 for the first time ever. In the scene, the aurora swirled to the north in front of me over mountains.  However, a  pale, confined, band of aurora ran perpendicular to the northern display, and stretched far to the south past a large, brilliant moon. In my camera it was cool blue/white in color and was in stark contrast to the green aurora that played on the northern horizon over the mountains of Juneau.  I posted the image to an aurora group on Facebook and labeled it a “proton arc” as so many before me had done. However, I received an interesting response from renowned aurora researcher Neal Brown – a true “proton aurora” is nearly undetectable by the human eye and the concept of a “proton arc” is a widespread misconception. The disagreement between the science and the public perception set my wheels turning, and even though I am not an aurora scientist, I would like to dissect why proton arcs are not truly visible.

Proton Arc, Hoonah, Alaska, Aurora Borealis
On September 20th, 2016 I thought I saw a “proton arc” in Juneau, however, it seems my misunderstanding of this auroral phenomenon is the same of many non-scientists.

There are two ways that auroras may be formed. Most auroras are formed when excited electrons collide with oxygen or nitrogen or if protons collide with nitrogen or oxygen. Electrons which are lighter and have a lot of energy result in the traditional, dancing auroras. Electron auroras emit light at many wavelengths including 630nm (red) and 427.9nm (blue). The second way that auroras can form is when protons collide with nitrogen and oxygen. The proton collisions result in emissions of 656.3nm (red) and 486.1nm (blue) (Lummerzheim et al. 2001).  Separation of these light bands are difficult because at 656.3 the emissions require a precise instrument to differentiate them from the electron aurora. The same can be said of the emissions at 486.1 which are nearly indiscernible from the electron emissions.  To quote Neal Brown’s response in the aurora group, “To prove it is a true proton arc one would have to use some sort of spectral discrimination to see if it contained only 656.3 and 486.1 nm emissions”. Aurora researcher Jason Ahrms had this to say in a detailed Facebook post – “We don’t use color, location in the sky, how long it’s been there, or anything like that to identify a proton aurora.”. This means that simply looking at an aurora with your eyes is not enough to determine if it is a proton arc – so why is it so commonly mislabeled. The mistake is likely an innocent use of scientific jargon; those posting the images (like me) simply did a brief search to confirm what they saw before spreading the lie themselves.

A chart of the light spectrum. Copyright : http://techlib.com/images/optical.jpg
A chart of the light spectrum. Copyright : http://techlib.com/images/optical.jpg

 

The Aurora Borealis shows off a pale display in Hoonah, Alaska which is often identified a "Proton Arc"
The Aurora Borealis shows off a pale display in Hoonah, Alaska which is often identified a “Proton Arc”

Although it is impossible to detect a proton aurora with your eyes, they have been successfully photographed once identified with instrumentation. Tony Phillips of Spaceweather.com discussed the phenomena with University of Alaska Fairbanks Researcher Jason Arhns.  His image below shows how difficult true differentiation between electron and proton aurora is. Where the proton arc has been identified is barely discernible from the aurora.

This proton arc was captured by Jason Ahrns of the University of Alaska, Fairbanks. The region fo the proton arc was determined from spectral instruments, but as you can see it is very similiar in form to electron auroras. Image copy right to Spaceweather.com

It was interesting to realize that my perception of what a proton arc was had been so wrongfully influenced by what I saw online. However, if the pale auroras being captured by photographers (like the photos below) are not truly proton arcs, what are they? Incredibly, as Jason Ahrns explains, to date there are is no known explanation for these pale, elusive aurora displays! They are a new opportunity for scientific exploration in the aurora research arena. I hope they keep us posted.

 

Citations:

http://pluto.space.swri.edu/image/glossary/aurora2.html

Lummerzheim, D., M. Galand, and M. Kubota. “Optical emissions from proton aurora.” Proc. of Atmospheric Studies by Optical Methods 1 (2001): 6.

news.spaceweather.com/protonarc/