OLYMPUS DIGITAL CAMERA

OLYMPUS DIGITAL CAMERA

Refuge Notebook: Genetic diversity of wildlife on the Kenai Peninsula is a mixed bag

There are 1,786 plant and animal species known on the Kenai National Wildlife Refuge. That’s extraordinary biodiversity for this latitude with perhaps another 3,000 species, by my estimation, yet to be found. George Shiras III, a famous National Geographic Society photographer, wasn’t kidding when he wrote that “were all of Alaska erased from the map except the Kenai Peninsula and its immediately adjacent waters, there would yet remain in duplicate that which constitutes the more unique and that which typifies the whole of this wonderful country.”

What makes the Kenai Peninsula so species rich is the intersection of the Sitka-spruce rainforest that colonized Prince William Sound with the drier white and black spruce boreal forest that extends from interior Alaska to the Cook Inlet. Combined with elevations ranging from sea level to 6,000 feet in the Harding Icefield, Mother Nature has created lots of ecological niches to be filled by species.

But because we live on a peninsula that is separated from the adjacent mainland by a narrow, 10-mile wide isthmus only recently de-glaciated, it’s logical to assume that plant dispersal and wildlife movement have been minimal with restricted genetic mixing. So although species diversity is relatively high, we would expect low genetic diversity within populations of most species on the Kenai Peninsula.

ADVERTISEMENT
0 seconds of 0 secondsVolume 0%
Press shift question mark to access a list of keyboard shortcuts
00:00
00:00
00:00
 

On the other hand, a paper published in Science in 2003 showed that the diversity of chloroplast DNA in European plant species was highest in areas where populations dispersing from northern and southern refugia collided in the aftermath of the last ice age. Such a place could be the Kenai Peninsula, an area in which at least some species may have been colonized by populations originating from both northern (Beringia) and southern refugia.

In fact, Caribou Hills, nunataks in the Harding Ice Field, and the northern part of the Kenai Mountains around Big Indian Creek were unglaciated during the last ice age, serving as local refugia for some flora and fauna. So genetic diversity might be low because it’s an isolated peninsula or it might be high because of post-Pleistocene colonization patterns.

It only gets more confusing because there are different ways of measuring genetic diversity. Modern genetics considers variation in nuclear DNA versus mitochondrial DNA. Unlike nuclear DNA, which is inherited from both parents and in which genes are rearranged in the process of recombination, there is usually no change in mitochondrial DNA from parent (usually the mother) to offspring. As such, mitochondrial DNA is a powerful tool for tracking ancestry through females.

Consider Kenai brown bears. A study published in the Canadian Journal of Zoology shows they have lower levels of mitochondrial DNA diversity than most other brown bear populations in Alaska, including the Kodiak Archipelago, but relatively high nuclear diversity. The former could result from a few reproductive sows that are highly successfully. Conversely, the latter could be due to high gene flow from males that disperse widely coupled with a tendency of females to stay close to home. As the authors suggested, determining which mechanism is in play is important for effective management of the Kenai brown bear population — there’s a danger of harvesting the wrong sows or too many boars.

In contrast, Kenai moose were found to have higher genetic diversity than populations elsewhere in North America and Scandinavia. Kris Hundertmark, originally at the Kenai Moose Research Center when this study was published in 1992, and his colleagues found that genetic diversity, as measured by polymorphic loci in liver and muscle samples from moose killed by collisions with vehicles, was unusually high. They suggested that this was so because the Kenai population likely originated from moose that survived the last ice age in nearby climate refugia (Beringia).

Wolverines from the Kenai Peninsula were similarly found to harbor a disproportionate amount of the mitochondrial diversity in North American populations. Furthermore, the Kenai population was considered somewhat distinctive, with a single unique haplotype. While the authors of this study, published in the Journal of Mammology, suggested that the genetic structure of our wolverine is not enough to warrant designation as a subspecies (recognized as Gulo gulo katschemakensis in 1918), they also acknowledged that our local population deserves special conservation attention.

Similarly, Trumpeter swans on the Kenai Peninsula were found to have slightly higher genetic diversity based on nuclear DNA than other populations in the western U.S. However, the authors of this study, from the University of Denver and U.S. Geological Survey, concluded that the diversity was not enough to warrant special management consideration.

At the end of the day, why should we care about genetic diversity? Genetic diversity plays an important role in the survival and adaptability of a species to environmental stressors such as rapid climate change, disease or contaminants, or how successful a native species might be in responding to competition from invasive exotic species. Variation in a population’s gene pool provides variable traits among the individuals of that population. Like making the wise decision to not put all your eggs in one basket, having multiple baskets of varying sizes ensures that someone gets home with at least some of the eggs. More genetic diversity means greater resilience in a population or species to survive environmental change, exactly what is needed to sustain our diverse biota on the Kenai Peninsula.

John Morton is the supervisory biologist at Kenai National Wildlife Refuge. You can find more information about the refuge at http://kenai.fws.gov or http://www.facebook.com/kenainationalwildliferefuge.

More in Life

These poached pears get their red tinge from a cranberry juice bath. (Photo by Tressa Dale/Peninsula Clarion)
A dessert to stimulate the senses

These crimson-stained cranberry poached pears offer a soft and grainy texture.

File
Minister’s Message: Palm Sunday — ‘Hosanna in the highest!’

The fact that Jesus came back to Jerusalem for Passover was an intentional decision of Jesus.

Cecil Miller took leave from Akron (Ohio) Police Department to join the U.S. Navy Seabees during World War II. When he returned to the force after his military service, he was featured in an October 1945 article in the Akron Beacon Journal.
The Man Called ‘Greasy’ — Part 2

Two distinct versions of Cecil “Greasy” Miller received the most publicity during his brief tenure on the southern Kenai Peninsula.

The cast of Seward High School Theatre Collective’s “Charlie and the Chocolate Factory” rehearse on Thursday, April 3, 2025. (Jake Dye/Peninsula Clarion)
‘A jaunt into a fantastical world’

Seward theater collective returns for second weekend of “Charlie and the Chocolate Factory.”

“Octoparty,” by Kenai Alternative High School student Adelynn DeHoyos, and “Green Speckled Ocean,” by Soldotna High School Student Savannah Yeager are seen as part of the 34th Annual Visual Feast Kenai Peninsula Borough School District Juried Student Art Show during an opening reception at the Kenai Art Center in Kenai, Alaska, on Friday, April 4, 2025. (Jake Dye/Peninsula Clarion)
‘Consume a bunch of art’

The 34th Annual Visual Feast showcases art by Kenai Peninsula Borough School District students.

Debbie Adams joins Kenai Mayor Brian Gabriel in cutting a ribbon during the grand opening of Debbie’s Bistro in its new location in the Kenai Municipal Airport in Kenai, Alaska, on Saturday, April 5, 2025. (Jake Dye/Peninsula Clarion)
Debbie’s Bistro opens in Kenai Municipal Airport

The menu features waffles, waffle pizzas and waffle sandwiches.

Photo courtesy of the Pratt Museum
During her brief time on the southern Kenai Peninsula, Dorothy Miller, wife of Cecil “Greasy” Miller, was a part of the Anchor Point Homemakers Club. Here, Dorothy (far left, standing) joins fellow area homemakers for a 1950 group shot. Sitting on the sled, in the red blouse, is Dorothy’s daughter, Evelyn, known as “Evie.”
The Man Called ‘Greasy’ — Part 1

There are several theories concerning the origin of Cecil Miller’s nickname “Greasy.”

Sweet potatoes, tomatoes, cauliflower, kale, onions and buckwheat are served in this rich, healthy salad. (Photo by Tressa Dale/Peninsula Clarion)
Salad, reinvented

This salad is exciting, complex, and has a much kinder kale to carb ratio.

File
Minister’s Message: Unexpected joy

This seems to be the way of life, undeniable joy holding hands with unavoidable sorrow.

Most Read