Rangeland Ecology & Management

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INFLUENCE OF CONIFER ENCROACHMENT ON BODY CONDITION OF GREATER SAGE-GROUSE
Author
Rabon, Jordan C.
Johnson, Tracey N.
Publisher
Society for Range Management
Publication Year
2018
Body

Recent studies of conifer encroachment into sagebrush steppe have documented negative impacts on demographic rates of greater sage-grouse (Centrocercus urophasianus), but few specific mechanisms have been tested. �Conifer densities may be positively related to predation risk, potentially altering time spent feeding by grouse, and closed conifer canopies can reduce floral food resources for sage-grouse.� Altered habitat characteristics resulting from conifer encroachment may influence body condition for grouse, which has implications for individual fitness.� Therefore, we evaluated the relationship of conifer canopy cover and stem density on body condition of sage-grouse during spring and summer of 2017 in southwestern Idaho.� Body condition was assessed using body mass and plasma protein levels, both of which are influenced by protein consumption. �We established two study sites from which we captured grouse, one with high levels of conifer encroachment and one with low encroachment. �We captured male and female grouse, fitted females with VHF radio-collars, and collected habitat data at known-use locations. �We collected 22 blood samples (n=12 hens and 6 males in high-encroachment sites and n=4 hens in low-encroachment sites). �High-encroachment use locations were characterized by average conifer stem densities of 2.08 stems (� 1.56, n = 24) at the 10-m scale, and 15.09 stems (� 15.32, n =44) at the 100-m scale.� Low-encroachment use locations had no conifers within 10 or 100 m.� Average plasma protein for females and males at high-encroachment sites was 4.99 g/dl (� 1.73) and 4.63 g/dl (� 1.17), respectively, and was 5.41 g/dl (� 1.47) for females at low-encroachment sites.� We will evaluate relationships of mass, accounting for body size, with conifer canopy cover and stem density at multiple spatial scales.� Results from this work will help elucidate specific mechanisms responsible for observed demographic rates and inform management efforts aimed at juniper removal in support of greater sage-grouse.

Language
English
Resource Type
Text
Document Type
Conference Proceedings
Conference Name
SRM Reno, NV