Date of Award:

5-2013

Document Type:

Thesis

Degree Name:

Master of Science (MS)

Department:

Wildland Resources

Committee Chair(s)

Terry A. Messmer

Committee

Terry A. Messmer

Committee

Randy T. Larsen

Committee

Frank P. Howe

Abstract

Greater sage-grouse (Centrocercus urophasianus; sage-grouse) populations have declined range-wide with some local populations exhibiting dramatic decreases. In 2009–2010, radio-marked hens (30 hens in 2009 and 30 hens in 2010) were translocated from Parker Mountain in south-central Utah to augment a rapidly declining population on Anthro Mountain in northeastern Utah. Thirty-two resident female sage-grouse on Anthro Mountain were also radio-collared from 2009–2012.

I compared population vital rates (i.e., nest and brood success, and survival) of resident and translocated hens in Anthro Mountain’s population to those of a translocated population in Strawberry Valley, Utah and the source population. Of these populations, Anthro Mountain sage-grouse exhibited the lowest average survival rates. Anthro Mountain survival rates were lower than range-wide estimates while hens in Strawberry Valley and on Parker Mountain had survival rates comparable to the range-wide estimates.

I evaluated the effect of the translocations on the Anthro Mountain population 4 years after the initial release by comparing survival rates, reproductive success, home ranges, and breeding habitat use of translocated and resident hens. I also examined if the translocations had any effect on Anthro Mountain lek count trends. Vital rates were similar for resident and translocated hens regardless of age or year. However, resident and previously translocated adult hens had highest reproductive success and newly translocated yearling hens had the lowest. Home ranges and breeding habitat use were comparable for each cohort (yearling vs. adult and resident vs. translocated hens). Lek counts gradually increased from 2010 to 2013 and a new lek was discovered in 2011. Based on these data, the translocation efforts appeared to have augmented Anthro Mountain’s declining population. The translocated sage-grouse successfully adapted to the release area and integrated into the resident population. Although lek counts indicated that the population increased, vital rates for both resident and translocated sagegrouse remained low compared to range-wide estimates. These observations suggest that other factors such as predation and habitat availability at the landscape scale may be inhibiting population growth. Managers should strive to mitigate limiting factors to stabilize this isolated population.

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