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.
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!
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 three examining wolf movement in the Yukon Flats, Alaska. 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.
Wolves are highly studied because they are charismatic, exhibit interesting pack behaviors, and are a key predator in the systems where they exist. Their behaviors including movement speed, movement distances, number of prey killed, and travel distances have been well documented in high prey-density systems, but practically no information exists on these behavior in low or very-low density systems. In an attempt to rectify that, a study was initiated in 2008 to understand the kill rate of moose by wolves in the Yukon Flats, Alaska, where moose are held at low densities (<0.20 per square kilometer) by predation. In an interesting twist, that study found wolves are maintaining kill rates (moose per wolf per day) similar to wolves in high prey density systems. Certainly these results counter what I would predict and lead to a natural question – how are wolves accomplishing such high kill rates in low-prey densities? A known mechanism is that wolves in the Yukon Flats keep small pack sizes to cope with low densities of prey; if you have fewer wolves in a pack, more nutrition is available per wolf during each kill. However, if wolves were traveling further or faster in this low prey-density system was unknown. I predicted that wolves in a low prey density system were traveling further, but not faster than wolves in a high prey-density system to maintain these kill rates. I also predicted they were selecting for river corridors when traveling.
To understand wolf movement, I used the same dataset from the 2008 kill rate study. It was composed of Global Positioning System (GPS) collars on six packs. Thanks to diligence in the kill rate study, I knew where kills occurred along each of the paths. For each pack, I characterized if the wolves were traveling, resting, at a kill site, or revisiting a kill site. These behaviors gave me enough information to calculate the rate of speed they were traveling, the distance they were traveling, the number of days traveling to make a kill, and how long they spent at kill sites. I also using a Generalized Linear Mixed Model to understand what landscape features were important for traveling wolves.
I found some interesting results, and put them in context of 16 comparable research papers of movements of wolves in high or medium prey-density systems. I am presenting the most applicable comparisons from the literature review (i.e., systems where moose are prey and studies where GPS collars were used) here. I found search time was slightly longer and search distance was 2.4 times greater in my low prey-density study area. Search time and search length are correlated together given that wolves are (almost) always hunting when moving. Due to that relationship, the search time is expected to go up as search days goes up. I found no evidence that wolves were handling prey longer or traveling faster in the low prey-density system. Those results were not surprising as one researcher found that handling time of moose was not significantly different among packs which varied in size from 2 – 20. Since wolves were not traveling faster in our system, it is probable that regardless of prey density, that on average wolves travel at their maximum comfortable speed that maximizes efficient travel.
I also found that wolves were utilizing river corridors and that they were selecting strongly against brushy habitat. In the Yukon Flats, that means they were selecting against thick stands of alder and willow. This was similar to previous studies where they found that wolves were able to travel 2.8 times faster if they used a river corridor rather than moving through a brushy environment. By using rivers, wolves were traveling faster and are likely taking advantage of increased prey density along river corridors.
The results of this work have some useful applications in helping us broadly understand wolf behavior. First, wolf territories are very large within low prey-density wolf systems. The mechanism that creates these large territories was unknown, but long-distance movements by wolves would create large territories by default. Next, back in the mid 1980s a researcher suggested that 0.20 moose per kilometer squared was the lowest density that wolves could persist at. Within the Yukon Flats, they are already persisting at lower densities than that, and since they are able to extend their travel distances to maintain kill rates it seems a minimum prey-density threshold could be much lower. A final implication of this work is that managers should expect wolf territories to increase in size if prey density decreases. In other systems (for instance deer in the mid-west), wolf territories should inflate in size as they move further in search of prey.
I look forward to presenting part four to you soon, which ties together moose hunting by wolves and humans by starting to understand the likelihood of competition.
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.
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?
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.
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
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.
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:
How do human hunters and wolves utilize their environment when pursuing moose?
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?
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.
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!
I have spent my last couple of days in Fort Yukon, Alaska. I was gathering data for my thesis as well as some data to fulfill some granting deliverables. As proof of that I offer you this key piece of evidence:
This was my first time into truly remote Alaska. In fact, Fort Yukon has no roads into it. It is far from the system of pavement which means your options are dogsled, snowmachine or airplane. I chose the latter. An interesting tidbit – villagers do drive cars, and the cars get there by barge when the Yukon is open and flowing. The flight up to Fort Yukon was very special because I got to experience the sunrise coming over the mountains. I attempted to capture the sunrise in my flight to Fort Yukon video. I will just warn you that the technique I used was a bit ‘experimental’. I wanted to shoot the video as a timelapse so I could get the sun rising as well as the plane in flight. That part worked; the sun definitely rises and the plane certainly moves. However, I didn’t account for the jerkiness of the plane when using a timelapse. I’ve done my best to edit to a smoother product, but you’ll still get tossed around a bit! It isn’t for the weak stomach :p. For a ‘smoother’ version of the flight, have a look at the flight from Fort Yukon to Fairbanks at the bottom which I think is a very cool video.
Small Antedote. For those who know my woes with laptops. I got off the plane in Fort Yukon and jumped into a vehicle with a stranger. Her name was Hannah. She thought I was someone else and I thought she was just picking me up for the office. So, off we went, but neither of us knew where we had to go :S . It didn’t take me long to figure out that I should head back to the airport and meet up with my actual pick-up. I had extra incentive though, I had left my laptop ON THE PLANE wedged between the plane and the seat. I talked to the Fort Yukon office and they weren’t able to contact the plane, but did put in a contact to the next village. That was lucky enough. On top of that I was fortunate that my plane was to return in 1.5 hours to pick up some freight before heading back to Fairbanks. When they arrived at 11:25 (and yes, minutes count when you are watching the time so closely) I was OVERJOYED to see the pilot step out of the plane with my laptop. Crisis averted!
THE FLIGHT TO FYU (Smoother flight at bottom 🙂 )
MY GRADUATE WORK
The purpose of this trip was to gather data for my graduate work. I’ll put down my current proposed thesis, so someday I can look back and read this. I’m sure I will have a good laugh. Currently I’m looking at competition between humans and wolves for the common resource of moose, in the Yukon Flats of interior Alaska. In this area moose populations are as low as anywhere in the U.S. or even the world. These low moose densities are unexpected, with exceptional habitat existing throughout the Yukon Flats. Moose in this system are thought to be controlled by wolves, which keep them at densities well below the carrying capacity of the land. This has been dubbed the ‘predator pit’. To get at competition I’m utilizing a collared wolf dataset through collaboration with the Fish and Wildlife Service, as well as Traditional Ecological Knowledge (TEK) from the Council of Athabascan Government. Those data – which comprise the purpose of my trip to Fort Yukon- were collected during interviews in the mid-2000s and serve as a useful tool to understand landscape usage by the villagers. My intent is to understand where they harvest moose. By comparing the two datasets using resource selection functions in GIS I am hoping to gain insights into competition based on how humans and wolves use the landscape when pursuing moose. I can’t thank enough CATG and FWS the opportunity to work with their data.
FORT YUKON AT NIGHT
Fort Yukon is a really cool place. Due to its location (the middle of nowhere) the night-scapes that occur there are second to none (but probably tied with many). I went out into the night and wandered around Fort Yukon passing through snow covered trees and by quiet houses. The full moon lit the landscape up so that in these pictures it appears to be daytime. You certainly could have read a book by it!
Unfortunately I did not get to partake or see much of life at the Fort Yukon. I spent most of my time indoors going through data and maps. However, before leaving I got a small tour of town. Here’s just some of the things to catch my eye.
By the way, I had this pronounced to me many times. If there is someone reading this who could phonically write it out for me that would be a huge help. I’m having a hard time getting it.
THE FLIGHT TO FAI (smoother video! :D)
The flight home was a much different flight. It started out clear, but then below us a cloud bank formed. However, just after we got past the Yukon Flats (as denoted by a rising mountain range) the skies cleared again and created a beautiful juxtaposition of clouds, light, and shade.
On the way home I met a really unique and talented individual. His name is Donovan Felix and he is currently on a mission to revive native tanning practices (brain tanning) in the interior. He was pulling on a chunk of moose hide while the flight was happing to make it supple part of his cargo for the trip was a caribou hide he had just been given. He specializes in caribou, but in recent years has started tanning moose asl well. Donovan is obviously very passionate about what he does and his mission. He was constantly giving me tips on how to tan hides, and what he was doing with the hide. In fact, what he is is doing is so novel that he was covered by www.culturesurval.org . Click the link to read the story. Also, if you are interested in learning about brain tanning UAF holds a workshop! http://www.uaf.edu/iac/traditional-learning/animal-hide-tanning/. This is certainly something that I will be looking out for this spring. I ended up giving Donovan a ride to town after we got off the plane.
The planes that bring people back and forth are not that big. They are carry as much freight and cargo as they do people. At each stop cargo is loaded and unloaded quickly and planes do not stay around long. I must say though their service is excellent and is needed by the villages. During my ride to Fort Yukon I sat next to Dr. Pepper and milk. Here’s a picture of the plane that got me back to Fairbanks.
Here’s the last bit. I’m really happy how this video turned out of the flight to Fairbanks. Have a look and let me know what you think!