Life Science Hour Seminar

Title:

Alaska wood bison restoration project

Abstract:

Wood bison existed in Alaska for the last 10,000 years. The last historic Alaska wood bison was shot around 1915, and after a decades long effort, the Alaska Department of Fish and Game released a new population into the wild in 2015. This seminar will provide you with the history of the project, the highlights of the epic effort to transport and release bison, monitoring information from the last 5 years, and where the project will go in the future.

About the Speaker:

Tom Seaton earned a BS in Wildlife Management from UAF in 1996. He did a work-study with the UA museum during his undergrad and caught small mammals for them and other museums in hundreds of remote locations across Alaska, Canada, Bolivia, and the Russian far east. He earned a Masters in Wildlife Biology from UAF in 2002. His thesis was focused on developing a moose browse survey technique that was sensitive enough to detect differences in range use between migratory and nonmigratory subpopulations. The technique was thoroughly tested by ADF&G over the following decade and is now used as the standard for moose browse surveys throughout Alaska and some other parts of the world. He has held several positions with ADF&G over the last 29 years from volunteer and technician up through the biologist series. He’s had the pleasure to work with all interior Alaska big game species, furbearers, and small game. He’s been involved in capture and handling of hundreds of big game animals and has flown more than 5,000 hours of aerial wildlife surveys. He continues to pilot the aircraft for the statewide caribou photocensus surveys annually, even though his main duty for the last 9 years has been the wood bison restoration project, mostly because of the breathtaking spectacle of seeing a hundred thousand Alaskan ungulates all together at once.

Life Science Hour Seminar

Title:

The mystery of the "Mammoth Hair": botanical studies complementing lake coring along a climate gradient on Baffin Island

Abstract:

I am working on a project on Baffin Island, sampling vegetation along a climate gradient from treeline to the retreating ice cap. The goal is to get a set of vegetation descriptions that match a range of climate conditions. This will be compared to the historical record of climate and vegetation retrieved from lake cores. It will give us a more complete picture of what the vegetation communities might have been like around these lakes in the past, and possibly what they might look like in the future. And that mysterious "mammoth hair"? Come and see photos of this stuff from the bottom of one of the lake cores, and see what you think about it.

About the Speaker:

Martha Raynolds is a plant ecologist, who samples and maps arctic vegetation. She got her undergraduate degree in Geography and Environmental Studies from Dartmouth College and her Master's in Botany from Virginia Tech. She came to Alaska in 1982 with her boyfriend, Sam, and worked for consulting companies and the US Fish & Wildlife Service, meanwhile getting married and having children. She started working at UAF in 1999, and completed her PhD here in 2009. She has been working at UAF in Skip Walker's Alaska Geobotany Center since then.

Thesis Defense

Title:

Seedling recruitment, genetic diversity, and secondary growth of deciduous shrubs in tundra disturbed by retrogressive thaw slump thermokarst on Alaska's North Slope

Abstract:

Since the 1970s, Arctic temperatures have risen by 2.7 ºC, more than twice that of lower latitudes. Tundra vegetation is historically growth-restricted, due to low decomposition rates, but warming is implicated in recent tall (≥ 0.5 m) woody shrub expansion. By 2100, some models predict shrubs may comprise ≥ 50% of tundra cover. Among the largest tundra plants, shrubs exert strong controls on hydrology, heat balance, nutrient cycling, and food webs. Shrubs may be key players in carbon storage and re-stabilization of thaw-deformed permafrost landscapes (thermokarst), however, shrub-climate feedbacks are complex and remain largely unknown. Warming associated with recent thermokarst activity includes large (≥ 1 ha) de-vegetated depressions on hillslopes caused by mass soil thaw, known as retrogressive thaw slumps (RTS). RTS have increased on Alaska’s North Slope by two thirds since the 1980s; some have released > 50% biodegradable C stores. Within decades, RTS near Toolik Lake support tall willow (Salix spp.) and dwarf birch (Betula nana) colonies. We quantified three plant response metrics in RTS of different ages (chronosequences) at two North Slope lakes: 1) recruitment (seedlings m-2 and percent germination of soil seedbanks), 2) clonal (asexual) growth of dominant vegetation (willow), and 3) secondary growth (annual rings) of dwarf birch and willow. We hypothesized that conditions in RTS support greater recruitment, genetic diversity, and growth than conditions in undisturbed moist acidic tussock tundra, and that the climate signal (June mean temperature) is amplified in RTS shrub ring widths. We found higher seedling density and seedbank viability associated with warm, nutrient-rich bare soil in recent RTS. Willow species richness was higher in RTS than in undisturbed tundra, but all willows showed high heterozygosity and low clonal growth. Ramets (branches) within clones were more widely spaced in RTS, suggesting RTS can fragment and disperse asexual propagules. Shrub rings in RTS were wider than in undisturbed tundra, but the climate signal present in most shrubs was largely not amplified in RTS shrubs, suggesting growth in RTS is strongly tied to local conditions. Most RTS shrubs had wider rings associated with greater September precipitation in the previous year, suggesting protective effects of early snow accumulations in RTS depressions. Our results demonstrate that some North Slope RTS support greater seedling recruitment and shrub growth than undisturbed tundra, and that RTS may be hotspots of arctic greening.

Life Science Hour Seminar

Title:

TBA