Tag Archives: Science

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.

DSC_5516

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/

 

Why Do Whales Try To Fly?

Last week I was floating under gray skies and windless conditions on a whale-watching boat outside of Hoonah, Alaska.  We drifted with engines off while Humpback Whales (Megaptera novaeangliae) fed around a rocky reef a hundred yards that was exposed by a shrinking tide. The distinct kee-kee-kee of hundreds of marbled murrelets, (Brachyramphus marmoratus, small pelagic birds) rang out around us and the bellow of sea lions droned from a distance green channel buoy. Towards that buoy an enormous nose broke through the surface and in a fraction of a second a mature Humpback Whale hung in the air with only the tips of its tail in the water. Its re-entry sent water far into the air with a crash. On its second breach I was ready and captured a series of shots as it arched into the water. My heart was racing as I soaked in what had just happened! Ultimately its leap from the water set my mind turning on why a whale would try to fly at all.

Mature Humpback Whales are gigantic creatures weighing between 45-50 tons (NOAA) and reaching up to 45 feet. I think Whitehead (1985) has it right when he states, “A Whale’s leap from the water is almost certainly the most powerful single action performed by any animal.” He found that a 12-m long adult humpback must travel at about 17 knots (3 times their normal cruising speed) to break the surface and expose at least 70% of their body. The energy required to thrust their entire body comes at an expense of energy, and begs to question about what they gain from it.  It is possible whales breach to communicate with others, to act aggressively towards another whale, to show strength, or to “play” (Whitehead 1985).

Humpback Whale Splash
A huge splash results from the breach of a humpback whale.

A lot of research on aerial behavior has tried to associate breaching with group dynamics. These studies have yielded interesting correlations. Whales breach more often in groups (Whitehead 1985). They were more likely to breach within 10km of another whale. Humpback whales surface activity (including multiple behaviors above surface) increases with group size and also occurred more with underwater vocalizations (Silber 1986). There also seems to behaviors which foreshadow breaching. For instance, breaching often comes after a tail lob. A tail lob is another visual and audio spectacle where the whale slaps its tail against the water.  Since breaching occurs more often in groups, these lends to the notion that it is a form of communication.

For some researchers, time spent on water results in findings that have little explanation. For instance, whales may breach more as wind speed rises (Whitehead 1985). Although support for why that would be is nearly impossible to determine, it has been shown that surface slaps can carry for several kilometers and the amount of sound created changes depending on what angle the whale strikes the water (Payne and McVay 1971, Deakos 2002 citing Watkins 1981). The distance that a breach can be heard is unknown, but it certainly surpasses the visual extent lending to the hypothesis that it is a form of communication, however, what message it conveys is unknown.

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By listening to whale vocalizations (for which humbacks are famous) that occur leading up to breaches, researchers found there is a relationship between the amount of vocalizations and breaches. Male to male interaction and above water behavior were often correlated with increased vocalization between males (Silber 1986). It is likely these vocalizations are aggressive and that males are plying for position or to mate with a female. The subsequent breach is probably an “exclamation” (Whitehead 1985) on the underwater vocalization rather than an attempt to harm the other whale during the breach.  Certainly it would demonstrate to a female the prowess and strength of the male (Whitehead 1985).

Insight into breaching behavior may be gained from researching other percussive behaviors. Deakos (2002) found that pectoral slapping varies with age class, sex, and social position. Females were likely to slap pectoral fins on the surface to indicate readiness to mate, while males often did it to compete with other males without full-on combat. Pectoral slapping was shown to be frequent in young whales and is likely an important piece of their development (I was fortunate to see a calf breaching last year).   However, pectoral slapping and frequent breaches from young and feisty individuals taper off as the whales mature and get older (Whitehead 1985). This likely means it not a form of play for older animals. From these findings in pectoral displays we likely assume that a breach from male, female or young calf means separate things.

Humpback Whale Pec Slap
The same humpback whale that breached also showed off pectoral slapping. The behavior went on for 5 or 10 minutes after the breach.
Humpback Whale Pec Slap
The resulting splash of a pec-slap from a humpback whale.

My review of the science and literature surrounding whale behavior is stumped by the same issue that plagues the field : the true question of “why” a whale breaches is illusive because “what” they are trying to convey is likely different for each whale.  Much like the way that we clap our hands different at sporting events, golf tournaments, at a wedding, or after a concert, whales likely use the clap of the water to communicate different feelings.  Answers are relegated to vaguery due to the inherent difficulty of researching an underwater animal. I can only conclude that whales breach to communicate.  It seems most plausible that humpback whales and other species breach to add emphasis to a message or to get a point across.

Cited:

Deakos. (2002). Humpback Whale (Megaptera Novaengliae) Commication : The context and possible functions of pec-slapping behavior on the Hawai’ian wintering grounds. Thesis.

Payne, R. S., & McVay, S. (1971). Songs of humpback whales. Science, 173, 585-597

Silber, G. 1986. “The relationship of social vocalizations to surface behavior and aggression in the Hawaiian humpback whale (Megaptera novaeangliae)”. Canadian Journal of Zoology. 64(10): 2075-2080

Watkins, William A. (1981). “Activities and underwater sounds of fin whales [Balaenoptera physalus].” Scientific Reports of the Whales Research Institute (Japan).

Whitehead, H. 1985. “Why Whales Leap”. Scientific American.

 

 

An Ivory Gull in Duluth, So What?

What does it mean when one of the least researched and understood marine birds in the Arctic turns up in Duluth, Minnesota 1,500 miles outside of its range? Locally, it ensures a birding rush of in-state and out-of-stater birders eager to see the rare bird, but what does it say about the global status of this unique bird? How can we use its presence to  educate ourselves of human impact on the high Arctic? Is the Ivory Gull (Pagophila eburnea) an indicator species of a greater issue in the Arctic? The suspicion that their unprecedented, 80% population decline over the last 20 years may be linked to mercury suggests they are.

Ivory Gull, Duluth
The Ivory Gull at Canal Park in Duluth sits on the piers a few hundred feet from the human observers on shore.

Population Free-fall of the Ivory Gull

Ivory Gulls are colonial birds, meaning that large numbers gather into groups to breed. By monitoring the nesting colonies of colonial birds, population trends may be established by researchers. However, surveys for Ivory Gulls  were only conducted in 1985 (Thomas and MacDonald, 1987) making it impossible to understand population trends. Compounding the lack of population data, Ivory Gulls are considered to be one one of the least understood marine birds. This is partly due to wintering along the ice pack between Greenland and Labrador ensuring they are not a bird which is in-sight of many people. However, indigenous knowledge has suggested declining populations since the 1980s (Mallory et al. 2003). In light of this, researchers  flew surveys of known nesting islands as well as newly found Islands in 2002 and 2003 and found something shocking. The number of nesting Ivory Gulls had declined by 80% since the 1980s (Gilcrest et al. 2005).

Ivory Gull, Identification
The Ivory Gull is a distinct bird with a blue bill, black feet, and stunning black tips on the wings.

Gilcrest et al. (2005) started to hypothesize at alternative reasons for the lack of gulls. They explored the possibility that the Ivory Gulls had simply shifted their nesting locations. However, a significant move is not inline with the known biology of the bird which generally move less than 1-2 kilometers.  Food sources of fish and carcasses have remained relatively stable in their study area giving them little reason to move. They noted that Ivory Gulls were not seen flying along the survey paths. It seems that the Ivory Gull was truly dying off.

Ivory Gull, Duluth, Minnesota
In Duluth, the Ivory Gull was gracious enough to land close to my camera, offering exceptional looks at the details of this beautiful bird.

 

The Driver of Change

Since the startling revelation of population decline, researchers have been trying to understand why Ivory Gulls are disappearing. It is probable that ice-pack changes and altered forage have contributed to the population decline (Gilchrest et al. 2005), but researchers think a stronger factor is in play . In his interview with the BBC World Service (full interview below) Dr. Alex Bond  hypothesizes that mercury is a leading stressor on Ivory Gulls based on findings that levels of mercury have risen 45 -50 times the levels found 130 years ago. There is strong evidence showing mercury levels in the eggs of Ivory Gulls is significantly higher than any other known marine bird. Braun et al. 2006 found that mercury in the eggs of Ivory Gulls were 2.5 times greater than even the next highest species, and were almost 3 times greater the amount which impairs reproductive success. Where is that much mercury coming from? And how exactly might it effect Ivory Gulls?

Ivory Gull, Underwings
The Ivory Gull in Duluth shows off its beautiful, white underwings.

To understand where the mercury is coming from, its important to know the basics of the mercury cycle. Mercury falls into the oceans from atmosphere pollution originating from coal-fired power plants, or is directly input from Alkali metal processing . There are also natural sources of mercury like volcanic eruptions and “volitilization of the ocean” (USGS 2000).  Once deposited in a waterbody, mercury becomes available to marine animals when it is transformed to methylmercury. Once in the that state, it moves up through the food chain into plankton, and then to fish, and finally to top level predators like birds and marine mammals.  Levels of mercury grows in organisms through bioaccumulation and biomagnifcation. To clarify that jargon, bioaccumulation means that the older you are, the more mercury you have since it is difficult to get it out your system once ingested. Biomagnification means that if you feed higher on the food chain you gain mercury more quickly. Marine mammals like seals have very, very high levels of mercury due to the effect of both bioaccumulation and biomagnifacation. With that information in mind it is easier to understand why Ivory Gulls accumulate mercury; they scavenge on carcasses of marine mammals and feed on fish which have high levels of mercury. They also have a high metabolic rate and consume more fish (Braun et al. 2006).

To date, the effect of mercury on Ivory Gulls has not been studied, but we can gather clues from looking at other species.  Common Loons (Gavia immer) also accumulate high levels of mercury due to eating fish (biomagnification) and having long lives (bioaccumulation). Evers et al. 2008 found a 41% decrease in fledged loon young in parents with >3 micrograms of mercury per gram of tissue compared to those with <1 microgram. They predict total reproductive failure of Common Loons if levels exceed 16.5 micrograms. Based on hundreds of hours of observation, they report that loons with elevated levels of mercury are lethargic and spend significantly less time foraging for food and less time taking care of their young. Each lead to fewer chicks growing to adulthood.  It is important to note in their study that mercury levels of a species change throughout their range due to climate, forage, and many other factors. Transferring the lessons of Common loons to Ivory Gulls, variation in  mercury levels changes are observed in Canada as well; in general levels of mercury increase from east to west in Canada. Although the effect of mercury on Ivory Gulls has not been directly studied and may effect gulls differently than loons, a good hypothesis for their decline is poor parenting and lethargy due to extraordinarily high levels of mercury. Only future research will help tease out the true effect of mercury on their decline.

Ivory Gull, Flying, Duluth
The Ivory gull in Duluth takes to the wing showing off its beautiful plumage and black feet.

When an Ivory Gull shows up in Duluth, Minnesota it is a chance to reflect. Reflect on the beauty of an animal. Reflect on the joy of seeing such a rarity. However, do not miss the opportunity to acknowledge that its prescense is out of the norm of the species and that an unseen driver which we do not fully understand is at play. Reflect on the fact that the impact of humans in a nearly un-inhabited region is undeniable. Human consumption of fossil fuels is depositing mercury into the Arctic at rates which may be directly effecting a species. The Ivory Gull is a red flag, an indicator that things are not right in the Arctic and that we should pay heed to what else may be going wrong that we just have not taken the time to study yet.

Sources:

http://www.bbc.com/news/science-environment-31921127

Braune, B. M., Mallory, M. L., & Gilchrist, H. G. (2006). Elevated mercury levels in a declining population of ivory gulls in the Canadian Arctic. Marine Pollution Bulletin, 52(8), 978-982.

Evers, D. C., Savoy, L. J., DeSorbo, C. R., Yates, D. E., Hanson, W., Taylor, K. M., … & Munney, K. (2008). Adverse effects from environmental mercury loads on breeding common loons. Ecotoxicology, 17(2), 69-81.

Gilchrist, H. G., & Mallory, M. L. (2005). Declines in abundance and distribution of the ivory gull (Pagophila eburnea) in Arctic Canada. Biological Conservation, 121(2), 303-309.

Mallory, M. L., Gilchrist, H. G., Fontaine, A. J., & Akearok, J. A. (2003). Local ecological knowledge of ivory gull declines in Arctic Canada. Arctic, 293-298.

Thomas, V.G., MacDonald, S.D., 1987. The breeding distribution and
current population status of the ivory gull in Canada. Arctic 40,
211–218.

USGS. 2000. http://www.usgs.gov/themes/factsheet/146-00/

https://soundcloud.com/bbc-world-service/ivory-gull-decline

The (nearly) Eternal Golden Hour

You are sitting on a warm, tropical, beach drinking a margarita. As you watch the day wane away the sun dips lower on the ocean horizon, and the landscape transforms into brilliant oranges and purples. Behind you the palm trees are bathed in orange, and the landscape has taken on incredible colors with accentuated shadows of even the shortest plant or sandcastle.  Almost certainly you bring out your cell phone or camera, because, like all photographers, you find the beauty of the Golden Hour to be irresistible, and you know the peak experience will be short lived.  Perhaps you even think to yourself that you wish the beauty of that light could last forever. What if it could?

The Golden Hour is also called the “magic hour” and for a landscape photographer there is no better time to be outside. The terms refer to the period of time when the sun is 6 degrees or less from the horizon. In many regions, like the balmy beach scene above, the moment as the sun sweeps through that 6 degree sweet-spot is relatively short. However, in Polar regions like Alaska, the winter sun has such as a low, southern trajectory, that the sunset-like colors almost never fade.

azelzen
This diagram demonstrates the concept of solar angle, which, as I found out, stays at <= 6 degrees for a full three months in Fairbanks, Alaska. http://www.esrl.noaa.gov/gmd/grad/solcalc/azelzen.gif

There are a variety of tools, apps, and websites to calculate the solar angle at your location.  I used the NOAA ESRL Sun Position Calculator to determine that in Fairbanks the sun dips to the 6 degree mark on October 24th, 2015 and will remain below 6 degrees until February 26th, 2016. To illustrate the effect of the polar magic hour the images below showcase the colors, and shadows achieved by the low-lying sun. For 3 months, the silver lining of our short, winter days is a luxurious landscape lit by an eternal Golden Hour.

Golden Hour Tamaracks
Although we often want to watch the sunset, the objects that it lights up behind us can be brought to life. These tamarack cones are bathed in the remarkable light of the Golden Hour
Golden Hour Angel Rocks
Because unique light of the Golden Hour, it offers the perfect opportunity for black and white transformations. Do you prefer the full color or black and white image?
Black and White Golden Hour
Because unique light of the Golden Hour, it offers the perfect opportunity for black and white transformations. Do you prefer the full color or black and white image?

I used several key resources for this article. If you are interested in calculating your sun angle check out :

http://www.suncalc.org/

http://www.esrl.noaa.gov/gmd/grad/solcalc/azel.html

http://www.golden-hour.com/

The Likelihood of Competition In The Yukon Flats

This entry details a portion of my thesis work at the University of Alaska Fairbanks, and is intended to communicate the findings of that work in a four part series. You are reading part four examining the likelihood of competition between wolves and humans. In order to make the article concise, you  may review the general background of this work in part one. I have truncated the background and methods of this work and focused on a portion of the results.

In parts two and three of this series I have been examining where humans in the Yukon Flats, Alaska are traveling to harvest moose and where/how wolves are traveling to harvest moose. A key finding of human access was that humans are mostly operating within 1500 meters of navigable water. During our wolf study I found that travel was based around river corridors. Based on this, I will conclude this series of articles by examining the “Beaver Creek” pack which overlapped strongly with navigable water.

I wanted to begin to understand the likelihood of competition around navigable waters for moose between humans and wolves. Remember, moose exist at extremely low densities and humans and wolves depend on them as a food resource. Therefore, I believe understanding competition is particularly important.  To understand the likelihood of competition, I applied my model of human access and overlapped it with wolf locations. I found that 75% of wolf use locations fell within the human access model.

Beaver Creek competition likelihood
This figure demonstrates the overlap in points between the human access model that I created (part two), and the wolf points (part 3). Beaver Creek pack falls on navigable water, and hence the likelihood of competition is greatest there.

My analysis does not contain temporally overlapping data. Wolf habitat selection may differ in September and October when humans are hunting moose.  Wolves could also rely on other prey species other than moose during that period.  Also, predation in the Yukon Flats extends beyond wolves. Bears take up to 85% of moose calves each spring. As such, my conclusion is just the beginning research for future biologists in the region. A complete analysis would encompass all predation on moose, be spatially and temporally overlapping, and would evaluate how many moose which are predated could be taken by humans. I hope you have enjoyed this four part series! A full copy of the thesis can be obtained by contacting me. Feel free to do so!

Starry Stitches

On the evening of December 8th this year, a wonderful series of phenomenon occurred. The sun went down, the aurora remained muted, brilliant stars of the Milky Way dappled the darkness, and a new moon sealed the deal for a night of very dark-skies.  I left the orange glow of Fairbanks behind and set off on a quest into the inky darkness of interior Alaska to photograph the Milky Way Galaxy.

When photographing the galaxy you are capturing the “galactic plane” which is the stars which spin out from the “galactic center“. Our sun and solar system reside on the edge of the galaxy, and give us the opportunity to look into it. However, depending on the season and the photographer’s location on the planet, the true center of the galaxy may not be available. In Fairbanks the galactic center would be visible in the summer when it is always light. During the winter the galactic plane of the Milky Way is visible,  but we do not get an opportunity to see the center because we are blocked from it by the planet.

MilkyWay
This image does a nice job of demonstrating our position in the disk of the milky way, and translating that disk to the “galactic plane”. Brilliant Milky Way images capture the nuclear bulge a the center of the Milky Way. The nuclear bulge is not visible from Fairbanks in the December. Image Credit : UCSD.edu

Fairbanks has not felt wind for over two months and snow  which would ordinary not persist with wind clung to the spruces encasing them . I angled my camera at the bases of those trees and slowly moved at up into the sky after each exposure with the goal of creating panoramic ‘stitches’ of the Milky Way. The method compounds the star density of the galaxy, and brings out distant features like a nebula seen in the upper left of several of the images. I hope you take to opportunity to view dark skies when you can!

A panoramic stitch of the Milky Way.
A panoramic stitch of the Milky Way and a nebula cluster in the upper left.
Milky Way Stitch
I was able to achieve the most definition of the Milky Way in this particular shot and misty veils of aurora float through for effect.
Milky Way Panorama
A tall vertical stitch of the Milky Way over a winter paradise.
Nebula cluster
The nebula cluster in this shot is pointed out by a snow covered spruce that arches into the picture from the left.
Milky Way and Nebula Cluster.
The Milky Way springs out of this crotch formed by these snow-covered spruces.
Milky Way Stitch
A distant planet, perhaps Venus, is particularly bright in this image.
Hoar Frost
The hoar-frost covered trees are a testament to the lack of wind in the region.

Quantifying Rural Hunter Access in Alaska*

This entry details a portion of my thesis work at the University of Alaska Fairbanks, and is intended to communicate the findings of that work in a four part series. You are reading part two. In order to make the article concise, you  may review the general background of this work in part one. I have truncated the background and methods of this work and focused on a portion of the results.

How do you get to a resource? Well, the simple answer is you “access” them. Depending on what you are trying to achieve, access may mean walking through the door of your local grocery store, driving onto a frozen lake and drilling a hole to jig up a fish, or driving a boat up a river to harvest a moose. The last example speaks directly to subsistence use patterns of communities in the Yukon Flats, Alaska. The objective of this part (specifically Chapter 1) of my study was quantify rural hunter access in Alaska.

Fort Yukon Aerial
This is an image for Fort Yukon in the spring. The Yukon River dominates the landscape. Fort Yukon is ~500 people, and the other communities I studied range from 30 – 100 people.

Let’s take a step backward quickly to look at why access matters. Game levels are traditionally managed to create yield for hunters, but it is critical that game populations be accessible to hunters. In the huge area of Alaska, creating high game densities in a remote region may have minimal benefit to hunters. Outside of Alaska, the effect of access on game populations and hunter success is not well understood, but increased access in Ontario may decrease moose, increased access in Idaho may increase elk mortality, and hunters in Minnesota concentrate their efforts within 0.8 km of roads 98% of the time. These studies suggest that access is important, but within the Arctic access has not been quantified despite being important for hunters, particularly those with a subsistence lifestyle.

It is important that game managers understand how many animals are being harvested to aid in setting regulations. In Alaska, this is accomplished by reporting harvest via a “harvest tag”. However, under-reporting of harvest via the harvest tag system is high in the subsistence communities of the Yukon Flats. This is due to a variety reasons centering around culture practices and feasibility of reporting. Within those communities, moose hunters are allowed one bull moose per season, and hunting most often occurs along rivers in September and October.

To understand where moose hunters are harvesting moose, I used an interview dataset collected in 2005 and 2007 by the Council of Athabascan Tribal Governments. The interviews were in conducted in five subsistence communities including Fort Yukon, Beaver Creek, Circle, Arctic Village, and Birch Creek. In the interview process, interviewees recorded harvest locations of moose on a topographic map. Based on that we determined they utilized rivers, a hunting method that is well documented in other research. However, the data allowed me go beyond just determining river use. I wanted to know : how far were users traveling from their community and from the river to harvest moose?

Yukon Flats Study Area
The study area was reviewed in part 1 of this four part series. This figure demonstrates the five communities that I studied, and their relation to each other.

I designed a method to quantify hunter access. I measured the straight-line distance of the harvest points from their community of origin, and the distance from the rivers. The idea behind this is that the hunter moved up river to a certain point, and then moved away from the river a certain distance. I grouped the resulting distances into five groups, and created a buffer around communities and rivers based on those distances. Within the buffers, I developed an “access index” with the goal of understanding the likelihood that a hunter would utilize an area. The access index was calculated as the number of points that fell inside of a buffer divided by the total number of points up to the edge of that buffer. So, based on that the maximum achievable value was 100% and either existed near community, or near the rivers. In effect, 100% means that 100% of the time, hunters were willing to travel that distance to harvest a moose.

Access Index Schematic
This schematic illustrates the calculation of the access index. I buffered rivers and each of the five communities base on the distances to harvest points. Within each of the buffers I calculated an access index, with the buffer around rivers and communities equaling 100%. In the first buffer hunters were 100% likely to travel at least that far to harvest a moose.
Access Index Final Model
This final model demonstrates how access if focused around rivers, and around communities. In this image, I added together of the access index around each of the five communities, and around the rivers.

The approach that I took was novel, and yielded some useful results. We found that on average hunters were traveling 0.9 ± 0.6 km from rivers and 47km ± 32km from their communities. Harvest was centered around rivers, and was happening most frequently near rivers. Some useful results!

There are a few ways that this model may be applied. First, I applied a region density of 0.0016 bull moose per square kilometer (remember, there are VERY low moose densities) to estimate the number of legal moose that are available to moose hunters. Based on hunter success of 27 – 46%, I estimated that 98 – 176 moose are harvested by hunters annually. Those numbers fell into the reasonable range of reported harvest in the region. Seeing as that’s the case, this method could help managers understand the amount of moose harvested, instead of relying on the extremely (regionally) variable harvest ticket system. Since this model enables an estimate of the number of animals taken around an access corridor, it could be used in other hunting systems where access is important. For instance in Alaska if a new road was created, how many moose would be harvested based on the new access. In Idaho, how many elk would be preserved if a road is closed?

Overall the results of this study have applicability within my study system, other subsistence systems in Alaska, and more broadly to regions where harvest of game is linked to access.  It demonstrates a novel method, and the results that can be gained through an interview process. In the next portion of this series, I will be examining wolf movement in this same area, which yielded some great results.

*The entirety of this work is in review with the Journal of Human Dimensions of Wildlife

Humans and Wolves in the Yukon Flats, Alaska

For the last 2.5 years in fulfillment of my Masters in Wildlife Biology at the University of Alaska Fairbanks, I have been researching the biological and human component of two key moose hunters (wolves and humans) within the Yukon Flats. I am happy to say that the full thesis is is completed and that I will be graduating in December! In my eyes, a critical next step is to make the results of this work public. Hence, I will be dedicating four blog entries to the subject. This first installment will introduce  the biology of the region, study area, and my research questions. My next installment will examine access of subsistence hunters to moose within the region. Following that I will look at movement of wolves in the region, and I will conclude by looking at areas were the likelihood of competition between wolves and humans for moose is highest.

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I conducted my research on human hunters and wolves in the Yukon Flats, Alaska. The predator-prey relations in Yukon Flats are unique because wolves and subsistence users pursue low-density moose that are held at a low-density equilibrium from predation. In fact, moose are at some of the lowest densities in the world (<0.20 moose per square kilometer).

Broadly I was interested in:

  1. How do human hunters and wolves utilize their environment when pursuing moose?
  2. How does understanding space use and movement and of humans and wolves pursuing moose help us understand competition for a scarce resource they rely on?

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The Yukon Flats National Wildlife Refuge is located in central Alaska, and extends nearly 220 miles east to west and 120 miles north to south.  It falls directly into a the boreal forest, which means if you walk around that you’ll find birch, black spruce, white spruce, alder and willow. Its namesake is the Yukon River which bisects the Flats, and the huge watershed of the Yukon River is fed by a plethora of rivers. In short, it is a water dominated system.

Yukon Flats
The Yukon Flats National Wildlife Refuge is located north of Fairbanks. It extends nearly 220 miles from east to west and 120 miles north to south.

Yukon Flats

Within the Yukon Flats there are several communities that are defined by their reliance on the land to harvest food, fuel, and fiber. Their subsistence lifestyle provides up to 85% of the resources they use including but not limited to moose, fish, and waterfowl. Since moose are such low densities but are critical for humans and moose,  it is interesting to research how moose are pursued, and where the likelihood of competition between humans and wolves in the highest. Answering any of those questions pertinent for managers.  My thesis integrated spatially explicit (i.e., locations) datasets of moose (Alces alces) hunters and of wolves (Canis lupus) to ultimately evaluate how two predators pursue a common resource, moose.

To this end, Chapter 1 of my thesis will be the second installment on this blog and focus on quantifying rural hunter access in the Yukon Flats, Alaska, through spatially-linked interviews. I chose this research topic because previous studies have only qualitatively surmised use area for subsistence resources by drawing boundaries around use areas. However, a quantitative approach can yield firmer management information. My novel approach provided pertinent insight into resource use for our system and created a method that may be applied to other systems. Using results generated from subsistence hunter interviews, I applied a model of access to moose hunting areas. Harvest reporting is low among the subsistence communities in our study, and from our results we generated an estimate of harvest based on game densities similar to the best data available on reported harvest. As such, my method may provide an alternative to, or supplement, harvest-ticket reporting.

In Chapter 2, I characterized movement paths (i.e., hunt paths) between moose kills by six packs in the Yukon Flats. The results of that work will be the third installment on this blog. The movements of wolves have been studied and documented in many high prey-density systems, but almost no information exists on their movements when prey is just dense (<0.20 /km2) enough for wolves to survive.

Finally, I will tie what I learned about wolf movement and human access to examine where competition between humans is the most likely. At that time, I hope to provide a full copy of the thesis for comprehensive reading of the research. I look forward to sharing this information with you, please feel free to ask questions!

 

 

Oh My, Fungi!

There have been many times when I stooped during my meanders through the woods to look at fungi, often not considering that I was only seeing the fruiting body of a large underground network of “hyphae” – small root-like structures which interact with many species in woodlands. Most of the time I only contemplate the color, shape, or size of the mushroom, and move on without ever being able to identify the species. I believe that experience is the same for many others. However, as I stood on the deck at the Folk School in Fairbanks, Alaska and watched a band of kids ranging from age 7-12 roam through the woods with mycologist Christin Anderson, I was excited to learn of the species they brought in!

I was astounded by the diversity of mushrooms brought forth – in a short time they had collected over 10 genus, and many more species. Functionally, the collection of mushrooms ranged from parasitic, to decomposing; one species even grew on decomposing mushrooms! We observed the variety of color and size of each by touching and looking as Christin explained that it is not possible to absorb the toxin of any mushroom through the skin, although most people believe that you can. It was certainly news to my ears! On top of that, I didn’t know the hallucinogenic compounds in mushrooms are the not same ones that can kill you; poisons and hallucinogens are separate things.

I think mushroom identification is the hardest part of being a mycologist, and is simply overwhelming for those of who are not mycologists. However, with Christin at the helm of at least identifying each of the mushrooms to genus, I was excited to look up information each. Here’s just a little of what I learned about the diversity of the world of mushrooms.  As a result of my research, I am in awe of the functionality that mushrooms play in Alaskan ecosystems.

Below are a images of the mushrooms collected. If you are receiving this post via email, you may have to visit the post to see them, since there are too many to be sent in the email.

 

Literature and websites:

http://ncbi.nlm.nih.gov

http://www.shroomery.org/

en.wikipedia.org

http://www.mushroomexpert.com/

http://mushroom-collecting.com/

http://www.wildmanstevebrill.com/

http://www.backyardnature.net/

Michelot, D., & Melendez-Howell, L. M. (2003). Amanita muscaria: chemistry, biology, toxicology, and ethnomycology. Mycological research, 107(02), 131-146.