Vegetative Characteristics of Sage-grouse Nesting and Brood Rearing Sites

Vegetative characteristics of 146 greater sage-grouse (Centrocercus urophasianus) nest sites and 48 brood rearing sites were compared with paired random sites to determine if hens were selecting sites with certain vegetative attributes at three study areas in central Montana in 2003 and 2004. Ninety-seven percent of all nest locations and 92% of all brood rearing locations were in Wyoming big sagebrush (Artemisia tridentata Nutt. ssp. wyomingensis Beetle & Young) plants. Therefore, only attributes of Wyoming big sagebrush plants were analyzed. Shrub characteristics such as percent cover, density (shrubs/m2), average shrub height (cm), nest shrub height (cm) and nest shrub production (g/shrub) were recorded. Herbaceous measurements such as forb cover (%), grass cover (%), total cover (%) and grass height (cm) were recorded. Sage-grouse hen nest sites had greater (P ≤ 0.05) average shrub height (36 vs 31 cm) and more (P ≤ 0.05) nest shrub production (55 vs 48 g/shrub) than random sites. There were no differences in sagebrush cover density or nest shrub height or any herbaceous characteristics between nest and random sites. Fifty percent of all nests were successful. Successful nest sites were not different from unsuccessful nest sites in any shrub or herbaceous component. There were no differences in shrub or herbaceous measurements between yearling and adult nest sites. Shrub and herbaceous characteristics of brood sites did not differ from random sites. Average shrub height was greater (P ≤ 0.05) for adult brood rearing sites compared to yearling sites (35 vs 31 cm). Brood site shrub cover was less (P < 0.05) than nest shrub cover (14 vs 21%). Our results suggest that even though nesting sage-grouse hens selected for taller and more productive Wyoming big sagebrush plants, these attributes did not improve nesting success. Grazing guidelines suggested to increase herbaceous vegetation may not improve nesting or brood rearing success. Although brood rearing vegetative characteristics were lower (P £ 0.05) in sagebrush cover and production than nesting sites, managers should not reduce Wyoming big sagebrush cover or production to emphasize one stage of sage-grouse production since this plant is vital for all life phases.

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Sage-Grouse Nesting, Brood and Winter Habitat Characteristics in Montana

Environmental Management and Sustainable Development ◽

10.5296/emsd.v5i1.9048 ◽

2016 ◽

Vol 5 (1) ◽

pp. 126

Author(s):

Jennifer Woodward ◽

Jenny Sika ◽

Carl Wambolt ◽

Jay Newell ◽

Sean Schroff ◽

...

Keyword(s):

Primary Objective ◽

Habitat Characteristics ◽

Shrub Cover ◽

Sage Grouse ◽

Winter Habitat ◽

Brood Rearing ◽

Study Sites ◽

Wyoming Big Sagebrush ◽

Central Montana ◽

Cover Density

Greater sage-grouse (Centrocercus urophasianus) habitat characteristics were studied in central Montana primarily on Wyoming big sagebrush (Artemisia tridentata Nutt. ssp. wyomingensis Beetle & Young) dominated rangeland. The primary objective was to compare shrub and herbaceous parameters within (use, random or non-use) and between seasonal habitats (nest, brood, winter). Two study sites (Musselshell and Golden Valley counties), and 2 years (2004 and 2005) were compared. Nest, brood, and random sites were compared for herbaceous cover, and grass height (n = 648). Nest, brood, random, winter use and winter non-use sites were evaluated for shrub cover, density, and height. All differences were considered significant at P ≤ 0.05. Sage-grouse nested in areas with greater total shrub cover and height, and taller live and residual grass than was randomly available. No differences were found between brood and paired random sites for any of the herbaceous or shrub parameters measured. Shrub cover and density were greater at winter use sites than non-use sites. Winter use sites had less shrub cover than nest sites. The nest and brood habitat had similar shrub cover, density, and height on the study area. Sage-grouse habitats should be managed to include sagebrush, forbs, and grass. Herbaceous vegetation was more important during nesting and brood rearing than during the winter. Therefore, some portions of sage-grouse habitat may benefit from management for greater herbaceous cover, but not at the expense of removing sagebrush. Sagebrush cover from 10 to 15 percent was the most consistent component of sage-grouse habitat.

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Wyoming Big Sagebrush and Herbaceous Cover Relationships

Environmental Management and Sustainable Development ◽

10.5296/emsd.v5i1.9302 ◽

2016 ◽

Vol 5 (1) ◽

pp. 179

Author(s):

Bok Sowell ◽

Carl Wambolt ◽

Jennifer Paddock ◽

Vanessa Lane ◽

Michael Frisina

Keyword(s):

Centrocercus Urophasianus ◽

Simple Linear Regression ◽

Sage Grouse ◽

Herbaceous Vegetation ◽

Big Sagebrush ◽

Wyoming Big Sagebrush ◽

Central Montana ◽

Relationship Of ◽

Best Fit

We measured 328 sites in northern, central, and southern Montana and northern Wyoming during 2003 to test the competitive relationship of herbaceous cover in the interspaces to Wyoming big sagebrush (Artemisia tridentata wyomingensis) cover. Long term annual precipitation at all sites was approximately 31 cm. Sagebrush and total herbaceous cover varied from 5 to 45 percent and 3.5 to 55 percent, respectively. Simple linear regression was the best fit model for predicting herbaceous cover from sagebrush cover using the highest Ra2 values as the model selection criteria. In northern Montana, herbaceous vegetation was predicted by sagebrush cover with the following model: Y = 37.4 – 0.61X (<a name="OLE_LINK2"></a><a name="OLE_LINK1"></a>Ra2 = 0.16, P < 0.001, n = 87). In central Montana, the model was Y = 14.0 – 0.00X (Ra2 = 0.00, P = 1.0, n = 155). In southern Montana, the model was Y = 35.9 – 0.39X (Ra2 = 0.14, P < 0.001, n = 86). When all sites were combined, the best fit model was Y = 23.7 – 0.15X (Ra2 = 0.01, P < 0.061, n = 328). This analysis determined that only 1 percent of the variation in herbaceous vegetation cover was associated with Wyoming big sagebrush cover. Management suggestions to reduce Wyoming big sagebrush in order to increase long-term herbaceous production for greater sage-grouse (Centrocercus urophasianus) would not be recommended.

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Reconstructing Greater Sage-Grouse chick diets: Diet selection, body condition, and food availability at brood-rearing sites

The Condor ◽

10.1093/condor/duy012 ◽

2019 ◽

Vol 121 (1) ◽

Cited By ~ 2

Author(s):

Kurt T Smith ◽

Aaron C Pratt ◽

Jason R LeVan ◽

Ashleigh M Rhea ◽

Jeffrey L Beck

Keyword(s):

Body Condition ◽

Isotope Analysis ◽

Field Measurements ◽

Sage Grouse ◽

Growth And Survival ◽

Dietary History ◽

Brood Rearing ◽

Big Sagebrush ◽

Chick Diet ◽

Selection Of

ABSTRACT Growth and survival of juvenile birds is nutritionally demanding, making the availability of major foods critical to population productivity. Access to nutritious foods for juveniles has important implications because poor foraging conditions during development could result in mortality, or reduced fitness in adulthood. Selection of brood-rearing habitats by female Greater Sage-Grouse (Centrocercus urophasianus) thus has broad implications to survival of juveniles and persistence of populations. Previous research using crop contents demonstrated that invertebrates and forbs comprise the major portion of sage-grouse chick diets for the first few months post-hatch. We coupled stable isotope analysis of feathers and field measurements to quantify chick diet and then correlated that with measures of chick body condition. We sought to reconstruct sage-grouse chick dietary history (2013–2015) using nitrogen stable isotopes to (1) evaluate whether selection of brood-rearing habitats by female sage-grouse was related to chick diet, and (2) assess the relationship between dietary consumption and body condition. Brood-rearing females selected habitats in areas where diet resources occurred in proportion to their availability, with the exception that females selected areas with greater forb abundance 4 weeks after hatch. Diet assimilation by chicks at brood-rearing locations was unrelated to the availability of forbs and invertebrates, but consumption of forbs increased with chick age. Chicks that assimilated proportionally greater amounts of plant-derived nitrogen in their feathers during their first week of life tended to weigh more and have longer wing chords. This relationship was similar between male and female chicks. The importance of quality foods for sage-grouse is well recognized and conservation efforts should aim to maintain functioning sagebrush ecosystems containing adequate brood-rearing habitats for juvenile sage-grouse; there remains a need to identify whether desirable effects are achievable when attempting to improve big sagebrush (Artemisia tridentata) habitats to benefit sage-grouse populations.

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