Tag Archives: research

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/

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.

P9230239

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?

IMG_20150913_152647869_HDR

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!

 

 

Colorful Seasons in Alaska

There is nothing more beautiful than a wildflower, but what about them makes them so beautiful? Surely the details in them are often astounding. Long stamens, unique petals, or colorful flowers may dazzle the eyes. Alternatively, the beauty of a wildflower may be linked to its overall surrounding. We often find them perched in rocky crags, in front of mountain vistas, at the edge of our favorite pond, or along our favorite hiking trail. Each wildflower represents a detailed, wild beauty, and that beauty grows as you consider the ecosystem and ecology that surround them.

Wildflowers excel at telling us the progression of summer. In Alaska, one of the first wildflowers of spring, pasque flowers, spring up in large purple and yellow blossoms welcoming the queen bumble bees which have just woken up from a long winter. Similarly, the early blooms of purple mountain saxifrage provide a critical nectar resource for queen bees. However, the timing, or phenology, of wildflowers in Alaska is changing with a warming climate. Changing flower timing can effect insects populations, and in turn birds by growing at different times than they have for milleniums. An example that we (I believe) have all noticed is a quickly melting snowpack. As snowpack melts earlier it has repercussions on when a flower starts to grow and bloom by moving it earlier, and buds may freeze in the still cold temperatures (Inouye 2008). This changes the plant’s fitness and also the flowers available to pollinators.  Although the genes of plants may have enough flexibility accommodate some of the effects of climate change, they may need to evolve to ultimately survive (Anderson, Jill T., et al. 2012).

This summer I’ve turned my lens to all of the wildflower blooms I can. I am actually pretty astounded by the number of species I have photographed and learned! When photographing them I both put them in their surroundings, and captured the fine details of their beauty. Some of these images are availble for purchase through my Fine Art America gallery. I hope you enjoy this extensive collection of the colorful seasons of Alaska! Photos are featured in the month that I captured them, rather than when they first start blooming.

June

July

August

 

If you’ve made it this far then I want to let you know that these images are available in a single page as well with some images that are not featured in this post:

http://ianajohnson.com/wildflowers-of-alaska/

Identification Sources:

If you are looking for Alaskan wildflower identification I cannot say enough about the utility of these two sites:

http://www.turtlepuddle.org/alaskan/wild/flowers-1.html

http://www.alaskawildflowers.us/

USDA Plant Database http://plants.usda.gov/java/

Literature

Inouye, David W. “Effects of climate change on phenology, frost damage, and floral abundance of montane wildflowers.” Ecology 89.2 (2008): 353-362.

Anderson, Jill T., et al. “Phenotypic plasticity and adaptive evolution contribute to advancing flowering phenology in response to climate change.” Proceedings of the Royal Society of London B: Biological Sciences 279.1743 (2012): 3843-3852.