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Your search keyword '"Lorelle I. Berkeley"' showing total 3 results
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3 results on '"Lorelle I. Berkeley"'

1. Phenology largely explains taller grass at successful nests in greater sage‐grouse

Author

Joseph T. Smith, Jason D. Tack, Kevin E. Doherty, Brady W. Allred, Jeremy D. Maestas, Lorelle I. Berkeley, Seth J. Dettenmaier, Terry A. Messmer, and David E. Naugle

Subjects
Centrocercus urophasianus, concealment, greater sage‐grouse, nest survival, phenology, Ecology, QH540-549.5
Abstract

Abstract Much interest lies in the identification of manageable habitat variables that affect key vital rates for species of concern. For ground‐nesting birds, vegetation surrounding the nest may play an important role in mediating nest success by providing concealment from predators. Height of grasses surrounding the nest is thought to be a driver of nest survival in greater sage‐grouse (Centrocercus urophasianus; sage‐grouse), a species that has experienced widespread population declines throughout their range. However, a growing body of the literature has found that widely used field methods can produce misleading inference on the relationship between grass height and nest success. Specifically, it has been demonstrated that measuring concealment following nest fate (failure or hatch) introduces a temporal bias whereby successful nests are measured later in the season, on average, than failed nests. This sampling bias can produce inference suggesting a positive effect of grass height on nest survival, though the relationship arises due to the confounding effect of plant phenology, not an effect on predation risk. To test the generality of this finding for sage‐grouse, we reanalyzed existing datasets comprising >800 sage‐grouse nests from three independent studies across the range where there was a positive relationship found between grass height and nest survival, including two using methods now known to be biased. Correcting for phenology produced equivocal relationships between grass height and sage‐grouse nest survival. Viewed in total, evidence for a ubiquitous biological effect of grass height on sage‐grouse nest success across time and space is lacking. In light of these findings, a reevaluation of land management guidelines emphasizing specific grass height targets to promote nest success may be merited.

Published
2018
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2. Survival of Sharp‐Tailed Grouse Under Variable Livestock Grazing Management

Author

Lorelle I. Berkeley, Megan C. Milligan, and Lance B. McNew

Subjects
Geography, Ecology, Rangeland management, Agronomy, Livestock grazing, General Earth and Planetary Sciences, Mixed grass prairie, Sharp-tailed grouse, Livestock management, Ecology, Evolution, Behavior and Systematics, Nature and Landscape Conservation, General Environmental Science
Published
2020
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3. Resource allocation effects on the timing of reproduction in an avian habitat specialist

Author

Jay J. Rotella, Lorelle I. Berkeley, Andrea R. Litt, Kyle A. Cutting, Aaron O'Harra, Sean R. Schroff, James A. Waxe, Mark Szczypinski, and Bok F. Sowell

Subjects
nutrient allocation, Ecology, Reproduction (economics), stable isotopes, Biology, reproduction, sage‐grouse, Habitat, endogenous, Resource allocation, Sage grouse, sagebrush, QH540-549.5, Ecology, Evolution, Behavior and Systematics, Nutrient allocation
Abstract

Variation in nutrient allocation can influence the timing of breeding and ultimately reproductive output. Time and space constraints might exist, however, if fewer food resources are available to meet the costs of reproduction early during the reproductive season. Here, for the first time, we test whether nutrient‐allocation strategies for reproduction in a shrub‐dependent avian species differ with timing of breeding in different ecoregions: a high‐elevation landscape, containing spatially complex vegetation (Rocky Mountains) vs. a low‐elevation, more homogenous landscape (Great Plains). We analyzed data collected from radio‐telemetry and stable isotopes to assess the degree to which endogenous (body) reserves are used for reproduction and whether variation in allocation strategies was associated with time of year, ecoregion, habitat quality (including sagebrush type and plant greenness), or maternal characteristics. Using a Bayesian statistical framework, we found that females relied on a similar amount of endogenous reserves for reproduction in first nesting and renesting attempts. Additionally, endogenous contributions declined more rapidly throughout the nesting season in the Rocky Mountains than in the Great Plains. Individuals in high‐ and intermediate‐elevation sagebrush types in the Rocky Mountains used similar amounts of endogenous reserves, whereas females nesting in low‐elevation sagebrush used less. Females nesting at intermediate elevations, which experience the greatest flush of new green vegetation during the nesting season, switched their reliance from endogenous‐to‐exogenous sources for reproduction as green vegetation became available during spring. Our study highlights adaptations of a nutrient‐allocation strategy across areas with varying levels of resources in time and space in a habitat specialist bird. Nutrient allocation by individuals residing in high‐elevation areas favors a strategy that mainly uses nutrients gained from wintering habitats, whereas individuals residing in low‐elevation areas mainly use exogenous sources for reproduction.

Published
2021
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