Cues for migratory species and implications for adaptability to changing seasons Ken Tape EPSCoR All-Hands Meeting May 24, 2012 Institute of Arctic Biology Alaska Cooperative Fish & Wildlife Research Unit

EPSCoR-2008

Apr 07

Elucidate relationships between ptarmigan herbivory, snow, and shrubs. Objective

Methods Manipulated Betula nana and Salix pulchra by staking them upright throughout winter. Compared browsing severity on manipulated and unmanipulated (laid down) shrubs. Made additional, more specific, measurements.

Manipulated vs. unmanipulated shrubs

Legacies of ptarmigan browsing intensity and snow depth can be inferred from the architecture of shrub branches… UnbrowsedRepeatedly browsed

…and shrub architecture hedge partial hedge

snow-ptarmigan-shrub interactions

Conclusions, Chapter 3 Ptarmigan (and other herbivores) strongly shape shrub architecture during spring migrations when snow is moderate to deep. The few unbrowsed buds in the low horizon on exposed willows suggests that late-winter forage may be limiting, and that the expansion of tall shrubs would increase ptarmigan populations. Ptarmigan may be facilitating floodplain succession to alder by preferentially browsing willow, much as moose do in interior Alaska.

Cues for migratory species and implications for adaptability to changing seasons Ken Tape 1, David Ward 2, David Gustine 2 EPSCoR All-Hands Meeting May 24, Institute of Arctic Biology, ACFWRU 2 USGS Alaska Science Center

Post-Doctoral USGS Projects: Changing Herbivore Habitat 1.Accelerated permafrost degradation facilitates vegetation change along the Arctic Coast of Alaska: Paul Flint, Brandt Meixell 2.Dynamics of the thaw lake system and succession of emergent vegetation: Tom Fondell 3.Advances in the date of snowmelt impact the timing of bird arrival: David Ward 4.Observed and Predicted Herbivore Responses to Earlier Snowmelt and Advanced Vegetation Phenology: Dave Gustine, Roger Ruess

Outline Background for studying snowmelt Some initial results

Lake 3 8/1/ /11/1948 7/27/2002

Lengthened Growing Season Asymmetrical toward spring, May 10 to May 2 Earlier disappearance of snow, onset of growing season Kuparuk River Peak Discharge Dates, Days after April 1st

Discharge does indeed reflect the decreasing snow fraction on the landscape

Acknowledgements Ptarmigan work: Alaska EPSCoR NSF award #EPS and the state of Alaska Recent work: USGS Alaska Science Center

Thank You

Approach: Caribou and Ptarmigan Deploy time-lapse cameras at numerous locations covering a gradient in snow cover, from snow-covered to snow-free, to record the number of caribou or ptarmigan in relation to snow fraction. If the number of individuals of a given species, such as caribou or ptarmigan, shows a preference for a certain snow cover fraction, then can we deduce that an earlier disappearance of snow would equate to an earlier migration? That ability to adapt by migrating sooner is likely an important factor in predicting which species populations will survive the shift toward earlier snowmelt and green-up