Elk following forage and fleeing to protected areas

Animated image depicting elk following forage and fleeing

Detailed Description

Elk begin on their low elevation winter range in January 2008. Gray dots represent locations from elk collared on Fossil Butte National Monument (outlined in black), while black dots represent elk collared near Cokeville, WY. As the landscape begins to green up (as measured by the instantaneous rate of green-up measured with satellites), the elk move north to higher elevations, generally following the green-up (day 113= April 23). They spend the summer in the more northerly portions of the study area. When archery season starts (September 1 ) the Monument elk all move back to the Monument, with the median date of migration of August 29). The elk collared near Cokeville, Wyoming remain on their summer grounds, which still contain reasonably high quality of forage, until snow and forage biomass declines (as measured by NDVI, day 305 = November 1). We found that early migration had a large effect (~16% decrease) on summer-fall forage availability for the elk near the Monument, as elk chose the safety of the Monument over the higher quality forage of summer range.  White values represent clouds and change in snow cover that masked the underlying forage quality. To learn more:  

Mikle, N, TA Graves, E Olexa.  2019. To forage or flee: lessons from an elk migration near a protected area.  Ecosphere. https://doi.org/10.1002/ecs2.2693

Details

Image Dimensions: 1500 x 1500

Date Taken:

Location Taken: WY, US

Credits

USGS: Nate Mikle and Tabitha Graves