Date of Award

8-2021

Degree Type

Report

Degree Name

Master of Natural Resources (MNR)

Department

Natural Resources

Committee Chair(s)

Thomas C. Edwards

Committee

Thomas C. Edwards

Committee

Mary Conner

Abstract

Land management practices in piñon-juniper woodlands can impact piñon pine (Pinus edulis, Pinus monophylla) obligates, including the pinyon jay (Gymnorhinus cyanocephalus). I summarized covariates surrounding pinyon jay nests to characterize pinyon jay nesting habitat at multiple scales relevant to both restoration work and pinyon jay life history. By referencing my results and overlaying my predictive models with proposed project sites, land managers can incorporate habitat metrics important to jays into restoration planning.

The Utah Division of Wildlife collaborated with Colorado Parks and Wildlife and the U.S. Fish and Wildlife Service to study pinyon jay occupancy in 2019 and 2020. This effort located 110 active nests and 24 pinyon jay colonies within the Colorado Plateau ecoregion. I identified habitat characteristics associated with jay nest and colony sites by analyzing remotely sensed covariates at four spatial scales centered on nests and non-nest (hereafter pseudo-absence) sites. These spatial scales included covariate values at the immediate nest site or pseudo-absence, at 300 m, at 3 km, and at 6 km.

Random forests model results highlighted differences in covariates between small and large scales: at nest locations or small scales, Juniperus spp. basal area (IQR: 27-77 ft²), distance to road (IQR: 117-342 m), and elevation (IQR: 1837-1981 m) were important. In comparison, heat load index (IQR: 0.78-0.83 units) and terrain roughness (IQR: 23-48 units) were more important at the 300 m and 3 km buffer size. Finally, within the largest buffer size of 6 km, percent canopy cover (IQR: 2.2-6.3) and canopy bulk density measures (IQR: 0.7-2.4 kg/m³) were most significant to nest habitat. Overall, land managers conducting restoration work can avoid impacts to potential pinyon jay nesting sites if they focus on terrain derivatives at smaller scales and canopy cover measures at larger scales during project planning. Furthermore, projects planners can reduce jay impact by referencing predictive nest habitat models at multiple spatial scales in the context of their project areas.

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