Shrub Canopy Cover Research Articles

Early post-fire plant succession in Peninsula Sandstone Fynbos: The first three years after disturbance

The early post-fire plant succession in fynbos vegetation in the Mediterranean-type climate area of South Africa was studied. Relatively little has been published on this early stage of plant succession in fynbos. Annual sampling over the first three post-fire years confirmed a steady, but relatively slow increase in plant canopy cover of shrubs and graminoids (mainly Restionaceae), whereas cover of geophytes and other herbs peaked in the first year and declined significantly, thereafter. Cover of annual plants increased each year, which may relate to the persistence of a relatively open vegetation cover by the third year. The responses of reseeder and resprouter species of the Restionaceae to the post-fire environment appeared to be habitat dependent. Cover of the reseeders increased rapidly in seep areas, but their recovery was distinctly delayed in dryland areas outside the seeps. Re-establishment of the many reseeder Erica species appeared to be delayed until the second post-fire year. Seed banks of these species were possibly negatively impacted by the fire, and required dispersal of seed from unburnt areas for recruitment. In contrast to some current generalisations, species richness appeared to increase after the fire; less certainly from the first to the second year, but more certainly from the second to the third year. Therefore, this study does not support a short-term monotonic decline in species richness after fire in fynbos.

Effects of shrub and canopy cover on the relative growth rate of Pinus pinaster Ait. seedlings of different sizes

• Introduction Shrubs are recognized as important tree regeneration niches. In this study, we experimentally analysed the effects of shrub presence, canopy cover (closed cover and open cover-gaps), and seedling size on Pinus pinaster growth.

Snow avalanche release in forest ecosystems: A case study in the Aosta Valley Region (NW-Italy)

Abstract Snow avalanches are among the most important disturbances that affect mountain ecosystems, influencing forest dynamics, establishment and mortality processes. At the same time, forests can affect the likelihood of avalanche release and can, in some cases, protect human settlements and infrastructure. Yet, since the ability of a forest to protect settlements is largely a function of its stand structure and composition, snow characteristics and topography, under particular conditions, avalanches can be triggered in forested areas. The aim of this work is to identify forested areas in the Aosta Valley (NW Italy) where at least an avalanche release occurred and to determine, through case studies, the main forest features that may prevent an avalanche release. Based on analysis of the regional avalanches cadastre, 5.4% of all the recorded avalanches released from a forested area. A sample of 15 avalanche sites with a release zone within a forested area was chosen, to compare the structural characteristics with neighboring forested areas located at the same altitude, aspect and slope, where no avalanches occurred. Most of the avalanches released at the end of winter and in the early spring, during periods when the danger level was equal or higher than 3-considerable. In our case studies, stem density (stems/ha) was the most important factor for snowpack stabilization, while the shrub canopy cover increased the probability of avalanche release. By enlarging the current database, it might be possible to relate forest structural characteristics to the snowpack structure, and consequently to avalanche release. In some cases, it might be preferable to use sustainable practices, such as suitable silvicultural approach, instead of permanent defense structures (less ecologic and often more onerous) in order to achieve a satisfactory avalanche protection.

A comparison of multi-spectral, multi-angular, and multi-temporal remote sensing datasets for fractional shrub canopy mapping in Arctic Alaska

Abstract Shrub cover appears to be increasing across many areas of the Arctic tundra biome, and increasing shrub cover in the Arctic has the potential to significantly impact global carbon budgets and the global climate system. For most of the Arctic, however, there is no existing baseline inventory of shrub canopy cover, as existing maps of Arctic vegetation provide little information about the density of shrub cover at a moderate spatial resolution across the region. Remotely-sensed fractional shrub canopy maps can provide this necessary baseline inventory of shrub cover. In this study, we compare the accuracy of fractional shrub canopy (> 0.5 m tall) maps derived from multi-spectral, multi-angular, and multi-temporal datasets from Landsat imagery at 30 m spatial resolution, Moderate Resolution Imaging SpectroRadiometer (MODIS) imagery at 250 m and 500 m spatial resolution, and MultiAngle Imaging Spectroradiometer (MISR) imagery at 275 m spatial resolution for a 1067 km2 study area in Arctic Alaska. The study area is centered at 69 °N, ranges in elevation from 130 to 770 m, is composed primarily of rolling topography with gentle slopes less than 10°, and is free of glaciers and perennial snow cover. Shrubs > 0.5 m in height cover 2.9% of the study area and are primarily confined to patches associated with specific landscape features. Reference fractional shrub canopy is determined from in situ shrub canopy measurements and a high spatial resolution IKONOS image swath. Regression tree models are constructed to estimate fractional canopy cover at 250 m using different combinations of input data from Landsat, MODIS, and MISR. Results indicate that multi-spectral data provide substantially more accurate estimates of fractional shrub canopy cover than multi-angular or multi-temporal data. Higher spatial resolution datasets also provide more accurate estimates of fractional shrub canopy cover (aggregated to moderate spatial resolutions) than lower spatial resolution datasets, an expected result for a study area where most shrub cover is concentrated in narrow patches associated with rivers, drainages, and slopes. Including the middle infrared bands available from Landsat and MODIS in the regression tree models (in addition to the four standard visible and near-infrared spectral bands) typically results in a slight boost in accuracy. Including the multi-angular red band data available from MISR in the regression tree models, however, typically boosts accuracy more substantially, resulting in moderate resolution fractional shrub canopy estimates approaching the accuracy of estimates derived from the much higher spatial resolution Landsat sensor. Given the poor availability of snow and cloud-free Landsat scenes in many areas of the Arctic and the promising results demonstrated here by the MISR sensor, MISR may be the best choice for large area fractional shrub canopy mapping in the Alaskan Arctic for the period 2000–2009.

Nest Predation of Greater Sage‐Grouse in Relation to Microhabitat Factors and Predators

ABSTRACT Nest predation is a natural component of greater sage‐grouse (Centrocercus urophasianus) reproduction, but changes in nesting habitat and predator communities may adversely affect grouse populations. We used a 2‐part approach to investigate sage‐grouse nest predation. First, we used information criteria to compare nest survival models that included indices of common raven (Corvus corax) abundance with other survival models that consisted of day of incubation, grouse age, and nest microhabitat covariates using measurements from 77 of 87 sage‐grouse nests. Second, we used video monitoring at a subsample of 55 of 87 nests to identify predators of depredated nests (n = 16) and evaluated the influence of microhabitat factors on the probability of predation by each predator species. The most parsimonious model for nest survival consisted of an interaction between day of incubation and abundance of common ravens (wravenXincubation day = 0.67). An estimated increase in one raven per 10‐km transect survey was associated with a 7.4% increase in the odds of nest failure. Nest survival was relatively lower in early stages of incubation, and this effect was strengthened with increased raven numbers. Using video monitoring, we found the probability of raven predation increased with reduced shrub canopy cover. Also, we found differences in shrub canopy cover and understory visual obstruction between nests depredated by ravens and nests depredated by American badgers (Taxidea taxus). Increased raven numbers have negative effects on sage‐grouse nest survival, especially in areas with relatively low shrub canopy cover. We encourage wildlife managers to reduce interactions between ravens and nesting sage‐grouse by managing raven populations and restoring and maintaining shrub canopy cover in sage‐grouse nesting areas.

Short-Term Fire Effects on Small Mammal Populations and Vegetation of the Northern Chihuahuan Desert

Fire is an important ecological factor in semidesert grass-shrub community dynamics, but there is a lack of designed field experiments documenting effects on vegetation and small mammals. We document effects of June prescribed fire on vegetation and small mammals on 20, 25-ha study areas in the Northern Chihuahuan Desert of Southern New Mexico, USA one month and one year posttreatment. Canopy cover of shrubs and grasses recovered to 68 and 27% of the preburn canopy cover, respectively, after one year. Prescribed burns during June enhanced short-term forb production by reducing competition from grasses and shrubs. Thirty thousand trap-nights yielded 1744 captures of 766 individuals of 15 small mammal species. Burns did not affect small mammal species richness and species diversity. Relative abundance of Merriam's kangaroo rats (Dipodomys merriami) was 91% greater on burned sites than on control sites one year postburn. Silky pocket mouse (Perognathus flavus) relative abundance was 221% greater on burned sites one year postburn. Chihuahuan Desert pocket mice (Chaetodipus eremicus) responded negatively to the fire, with relative abundance 170% greater on control sites (). Burning produced short-term benefits for two heteromyids, Merriam's kangaroo rats and silky pocket mice.

Nest Site Selection by Greater Sage‐Grouse in Mono County, California

ABSTRACT Loss of nesting habitat is believed to be a factor in the decline of greater sage‐grouse (Centrocercus urophasianus) throughout its range. Few data are available for sage‐grouse in Mono County, California, USA, in the most southwestern portion of the species’ range. We studied habitat selection of nesting sage‐grouse in Mono County, California, from 2003 to 2005 by capturing and radiotracking females to identify nesting locations. We sampled vegetation at nest sites and randomly selected sites within 200 m of nests and within each of 5 subareas within Mono County. Nest sites were characterized by 42.4 ± 1.3% (x̄ ± SE) shrub canopy cover, 10.5 ± 1.0 cm residual grass height, and 2.7 ± 1.0% residual grass cover. Shrub cover was the only variable found to differentiate nest sites from randomly selected sites. Unlike some other studies, we did not find understory vegetation to be important for selecting nest sites. Mean shrub cover was 38.7 ± 1.5% at random sites within 200 m of nests and 33.6 ± 1.6% at random sites at the approximate scale of home ranges, indicating that nesting females selected nesting areas that contained denser shrubs than their home range, and nest sites that contained greater shrub cover than the vicinity immediately surrounding nests. Our results suggest that managers should consider managing for greater shrub cover in Mono County than what is currently called for in other parts of sage‐grouse range and that management for sage‐grouse habitat may need to be tied more closely to local conditions.

Status and habitat requirements of Physaria thamnophila, an endangered species of Tamaulipan thornscrub

Abstract Physaria (Lesquerella) thamnophila (Brassicaceae; henceforth Physaria) is an endangered herbaceous perennial plant of remnant patches of Tamaulipan thornscrub near the southern Texas border. Six years of censuses of four populations of Physaria were analyzed. Quantitative data were collected to describe the plant community in the four sites. There was no overall trend in population size, but fluctuations in observed numbers of plants among years were extremely large: a single census cannot provide a reliable assessment of a population of this species. Seedling numbers were positively related with shrub canopy cover. However, there were many more Physaria plants in the brush-cleared portion of one site than in its uncleared portion. Seedling survival may be facilitated by anything that reduces movement of the highly erodible soils of these sites.

Postfire Recovery of Two Shrubs in the Interiors of Large Burns in the Intermountain West, USA

ABSTRACT. Shrub canopy cover can take between 10 and >50 years to recover to predisturbance levels following fire in sagebrush communities. The high degree of unpredictability of shrub recovery following prescribed fires and wildfires makes it difficult to prioritize restoration efforts and develop long-term plans for restoring or maintaining the integrity of sagebrush communities. Our overall goal was to develop a hypothesis based on descriptive data that describes the temporal pattern of recruitment for 2 important shrubs, Artemisia tridentata Nutt. ssp. vaseyana (Rydb.) Beetle and Purshia tridentata (Pursh) DC., in the interiors of large burns where little seed input from surviving shrubs occurs. We had 2 primary questions: (1) are there distinct temporal patterns of recruitment in the interiors of large burns that determine the recovery rate of the shrub canopy layer for species largely dependent on seedlings for reestablishment and (2) can we generate hypotheses that explain this variation in shrub r...

Nesting Ecology and Reproductive Success of Lesser Prairie-Chickens in Shinnery Oak-Dominated Rangelands

Abstract I evaluated the effects of habitat composition on Lesser-Prairie-Chicken (Tympanuchus pallidicinctus) breeding season habitat use in shinnery oak (Quercus havardii)-dominated rangelands. Female Lesser Prairie-Chickens selected nest sites with greater visual obstruction, shrub height, shrub cover, and litter compared to adjacent rangeland sites with most (n = 21) selecting nest sites within 1 km of the leks on which they were captured. Successful nests were in areas with greater visual obstruction and were characterized by greater canopy cover of shrubs than at unsuccessful nests. Nesting habitat did not appear to be limited on the study area and use of shinnery oak-dominated rangelands did not reflect poor or scarce nesting habitat. Management that protects both the shrub and herbaceous component of the shinnery oak community is essential for maintaining nesting habitat for Lesser Prairie-Chickens in east-central New Mexico.

Factors affecting nest-site selection and nest success of translocated greater sage grouse

Translocations have been used for decades to restore or augment wildlife populations, yet more often than not, little to no data and/or arbitrary means are used for determining translocation success. The objectives of our study were to describe nesting habitat utilised by the greater sage grouse translocated into an extant population and to identify factors related to nest success, thereby demonstrating the adaptability of the birds to their new environment and producing one measure of long-term translocation success. We trapped female grouse individuals during the spring on and near leks of source populations, fitted them with radio-transmitters, and released them in the morning onto an active lek in an extant population in Strawberry Valley, Utah. We monitored translocated females for nesting activity and documented nesting attempts, nest success, clutch size and embryo viability. Data were recorded on habitat variables associated with nest sites and paired-random sites, including factors known to be important for resident females that nested successfully. We used logistic regression and an a priori information-theoretic approach for modelling nest v. paired-random sites and successful v. unsuccessful nest sites. Our analyses suggested that crown area of the nest shrub and percentage grass cover were the two variables that discriminated between nest and paired-random sites. Females that nested successfully selected sites with more total shrub canopy cover, intermediate size-shrub crown area, aspects other than NW and SE, and steeper slopes than for unsuccessful nests. After being translocated from distant sites with differing habitat characteristics, these birds were able to initiate a nest, nest successfully, and select micro-habitat features similar to those selected by resident sage grouse across the species range. Our results demonstrate the adaptability of the translocated female sage grouse individuals and produce one tangible measure of long-term translocation success.

Postfire Recovery of Sagebrush Communities: Assessment Using Spot-5 and Very Large-Scale Aerial Imagery

Abstract Much interest lies in long-term recovery rates of sagebrush communities after fire in the western United States, as sagebrush communities comprise millions of hectares of rangelands and are an important wildlife habitat. Little is known about postfire changes in sagebrush canopy cover over time, especially at a landscape scale. We studied postfire recovery of shrub canopy cover in sagebrush-steppe communities with the use of spectral mixture analysis. Our study included 16 different fires that burned between 1937 and 2005 and one unburned site at the US Sheep Experiment Station in eastern Idaho. Spectral mixture analysis was used with September 2006 Systeme Pour l’Observation de la Terre-5 (SPOT-5) satellite imagery to estimate percent shrub canopy cover within pixels. Very large-scale aerial (VLSA) imagery with 24-mm resolution was used for training and validation. SPOT-5 image classification was successful and the spectral mixture analysis estimates of percent shrub canopy cover were highly correlated with the shrub canopy cover estimates in the VLSA imagery ( R 2 = 0.82; P Artemisia tridentata Nutt. subsp. vaseyana [Rydb.] Beetle) communities recovered approximately 27 yr after fire, with an average shrub cover of 38%. These results are consistent with other field-based studies in mountain big sagebrush communities.

Chukar Watering Patterns and Water Site Selection

Abstract We evaluated chukar (Alectoris chukar) watering patterns as well as habitat variables influencing water site selection in western Utah. Motion-sensing cameras and chukar dropping counts were primary techniques to evaluate watering patterns. We took vegetative and other habitat measurements at each water source (n = 43) to discriminate use from nonuse sites using logistic regression. Chukars watered during daylight hours with a modal hour from 1200 hours to 1300 hours daylight savings time. Annual patterns suggest limited use of water sources from November to May with first observed visits occurring in June and last observed visits in October. Shrub canopy cover was the only variable to discriminate between site types (P 0.05). Chukars seem to have a loose shrub canopy threshold near 11% that is likely due...

Factors Affecting Nest Survival of Greater Sage‐Grouse in Northcentral Montana

Abstract: We studied greater sage‐grouse (Centrocercus urophasianus) in northcentral Montana, USA, to examine the relationship between nest success and habitat conditions, environmental variables, and female sage‐grouse characteristics. During 2001‐2003, we radiomarked 243 female greater sage‐grouse, monitored 287 nests, and measured 426 vegetation plots at 4 sites in a 3,200‐km2 landscape. Nest survival varied with year, grass canopy cover, daily precipitation with a 1‐day lag effect, and nesting attempt. In all years, daily survival rate increased on the day of a rain event and decreased the next day. There was temporal variation in nest success both within and among years: success of early (first 28 d of nesting season) nests ranged from 0.238 (SE = 0.080) in 2001 to 0.316 (SE = 0.055) in 2003, whereas survival of late (last 28 d of nesting season) nests ranged from 0.276 (SE = 0.090) in 2001 to 0.418 (SE = 0.055) in 2003. Renests experienced higher survival than first nests. Grass cover was the only important model term that could be managed, but direction and magnitude of the grass effect varied. Site, shrub and forb canopy cover, and Robel pole reading were less useful predictors of nest success; however, temporal and spatial variation in these habitat covariates was low during our study. We note a marked difference between both values and interpretations of apparent nest success, which have been used almost exclusively in the past, and maximum‐likelihood estimates used in our study. Annual apparent nest success (0.46) was, on average, 53% higher than maximum‐likelihood estimates that incorporate individual, environmental, and habitat covariates. The difference between estimates was variable (range = +8% to +91%). Management of habitats for nesting sage‐grouse should focus on increasing grass cover to increase survival of first nests and contribute to favorable conditions for renesting, which should be less likely if survival of first nests increases.

Long-term changes in an oak forest's woody understory and herb layer with repeated burning1

Although fire exclusion is thought to be linked with declining plant diversity in oak forests, few studies have examined long-term changes in their shrub and ground layers resulting from repeated burning. In this study, we compare the composition and structure of woody understory and ground layer vegetation in burned and unburned oak forest after 17 years of annual dormant season low-intensity burns. Over time, burned forest had 97% reduction of shrubs and small saplings, but only 38% loss of stems in the > 5–10 cm size class. Canopy openness was similar in burned and unburned forest plots prior to the onset of burning, but it was significantly greater in burned forest after 17 years of fire. Ground layer vegetation structure also changed significantly, with responses differing by guilds. Spring herbs were the dominant guild before burning and did not change over time. However, cover and abundance of summer herbs increased over time in burned forest, probably in response to greater light assimilation under the more open canopy. This resulted in greater overall species richness in burned plots without loss of the spring herbs. Burning eliminated most alien shrubs, although common buckthorn persisted in small numbers. The alien herb garlic mustard also persisted and had greater abundance in burned plots, apparently by re-colonizing from unburned micro-habitats and adjacent forest. These results indicate that long-term burning can eliminate shrub and small sapling canopy cover, thereby increasing canopy openness and promoting greater richness and cover of summer forbs. Fire also probably had a positive effect on seedling establishment through removal of litter. Resulting tradeoffs to this gain in diversity include loss of native vines, shrubs, understory trees and forest interior bird habitat, as well as persistence of alien plants.

Stocking Rate and Weather Impacts on Sand Sagebrush and Grasses: A 20-Year Record

Abstract Understanding how stocking rate or grazing intensity affects the abundance of common plant species is fundamental to the sustainable management of rangelands. We had the unique opportunity to determine the impact of stocking rate on shrub canopy cover and grass basal cover in a sand sagebrush (Artemisia filifolia Torr.) grassland of the Southern Plains, United States. Treatments were imposed over a 20-year time span that included an entire precipitation cycle from wet to dry and back to wet conditions. From 1941 until 1951, continuous stocking treatments of 41, 53, and 82 animal-unit-days ha−1 (AUD·ha−1) were imposed with straight-bred Hereford steers (initial weight of 213 kg ± 11 SE) for about 320 days from mid-November to late September of the next year. From 1952 through 1961, the experimental pastures were grazed yearlong by cow-calf pairs at 45, 60, and 87 AUD·ha−1. Canopy cover of shrubs and basal cover of grasses were measured by the line-intercept method in 1940, 1942, 1949, 1955, 1958, ...

Stocking Rate and Weather Impacts on Sand Sagebrush and Grasses: A 20-Year Record

Understanding how stocking rate or grazing intensity affects the abundance of common plant species is fundamental to the sustainable management of rangelands. We had the unique opportunity to determine the impact of stocking rate on shrub canopy cover and grass basal cover in a sand sagebrush (Artemisia filifolia Torr.) grassland of the Southern Plains, United States. Treatments were imposed over a 20-year time span that included an entire precipitation cycle from wet to dry and back to wet conditions. From 1941 until 1951, continuous stocking treatments of 41, 53, and 82 animal-unit-days ha-1 (AUD ha-1) were imposed with straight-bred Hereford steers (initial weight of 213 kg +/- 11 SE) for about 320 days from mid-November to late September of the next year. From 1952 through 1961, the experimental pastures were grazed yearlong by cow-calf pairs at 45, 60, and 87 AUD ha-1. Canopy cover of shrubs and basal cover of grasses were measured by the line-intercept method in 1940, 1942, 1949, 1955, 1958, and 1961. Canopy cover of sand sagebrush was not affected by stocking rate. Individual grass species exhibited positive and negative responses to stocking rate in some years, but no grass species responded to stocking rate in a single direction over the entire length of this long-term study. Stocking rate effects were most obvious under favorable conditions of high precipitation, but these effects were absent during drought. Climatic variability and slope gradient exerted the primary controlling influences on sand sagebrush-grasslands in the Southern Great Plains when stocking rates were within the bounds tested in this study.

Effects of Invasive Exotic Grasses on South Texas Rangeland Breeding Birds

AbstractInvasive exotic plants are a major threat to many species of wild birds. When these plants become established and widespread, the floristic composition of native plant communities becomes simplified, which can result in long-term and often irreversible habitat degradation for birds and other animals. Until recently, few studies have focused on the effect of invasive exotic grasses on breeding birds in southwestern rangelands. During the 2001 and 2002 breeding seasons (May-June), we compared the abundance and species richness of breeding birds, native flora, and arthropods on South Texas rangeland plots dominated by native grasses and plots dominated by two invasive exotic grasses, Lehmann lovegrass (Eragrostis lehmanniana) and buffelgrass (Cenchrus ciliaris). Native-grass cover was >400% greater on native-grass sites than on exotic-grass sites. Forb and grass species-richness were higher on native-grass sites. Shrub canopy cover, bare ground, and vegetation height measurements were similar on native-grass and exotic-grass sites. Overall bird abundance was 32% greater on native-grass sites than on exotic-grass sites. Lark Sparrows (Chondestes grammacus) were 73% more abundant on native-grass sites. Four other species—Black-throated Sparrow (Amphispiza bilineata), Northern Mockingbird (Mimus polyglottos), Northern Bobwhite (Colinus virginianus), and Cassin’s Sparrow (Aimophilla cassini)— were 26–70% more abundant on native-grass sites. The guild of birds that foraged on the ground under open brush canopies was almost twice as abundant on native-grass sites. Arthropod abundance was 60% greater on the native-grass site we sampled. Specifically, spiders, beetles, and ants were 42–83% more abundant on a native-grass site than on a buffelgrass site. Compared with rangelands dominated by native vegetation, areas dominated by Lehmann lovegrass and buffelgrass in South Texas appear to provide less suitable habitat for breeding birds, especially for bird species that forage on or near the ground.Efectos de Pastos Invasores Exóticos en las Aves que Nidifican en los Campos de Pastoreo del Sur de Texas

EFFECTS OF INVASIVE EXOTIC GRASSES ON SOUTH TEXAS RANGELAND BREEDING BIRDS

Abstract Invasive exotic plants are a major threat to many species of wild birds. When these plants become established and widespread, the floristic composition of native plant communities becomes simplified, which can result in long-term and often irreversible habitat degradation for birds and other animals. Until recently, few studies have focused on the effect of invasive exotic grasses on breeding birds in southwestern rangelands. During the 2001 and 2002 breeding seasons (May-June), we compared the abundance and species richness of breeding birds, native flora, and arthropods on South Texas rangeland plots dominated by native grasses and plots dominated by two invasive exotic grasses, Lehmann lovegrass (Eragrostis lehmanniana) and buffelgrass (Cenchrus ciliaris). Native-grass cover was >400% greater on native-grass sites than on exotic-grass sites. Forb and grass species-richness were higher on native-grass sites. Shrub canopy cover, bare ground, and vegetation height measurements were similar on nat...

GREATER SAGE-GROUSE NESTING HABITAT SELECTION AND SUCCESS IN WYOMING

Nesting habitat degradation and its negative effect on nesting success might contribute to the recent population and distributional declines of greater sage-grouse (Centrocercus urophasianus) throughout North America. We used radiotelemetry to locate greater sage-grouse nests in 7 different areas of central and southwestern Wyoming between 1994 and 2002; we studied each area for 2 to 4 years. Using binary logistic regression, we compared microsite vegetal data collected at nests (n = 457) and random (n = 563) sites and successful (n = 211) and unsuccessful (n = 238) nests to test hypotheses concerning greater sage-grouse nesting habitat selection and vegetal conditions associated with nesting success. We used Akaike's Information Criterion (AICc) and model averaging to make inference about the weighted support for the importance of individual habitat variables through the comparison of sets of competing models. Selected nest sites were located in areas with increased total shrub canopy cover (relative importance [RI] = 1.00), residual grass cover (RI = 0.47), and residual grass height (RI = 0.77) compared to random sites. Successful nests had increased residual grass cover (RI = 0.43) and height (RI = 0.48) relative to unsuccessful nests. Additionally, annual nest success rates (i.e., above vs. below our study's average) were related to the preceding year's spring (Apr–May; RI = 0.44) and winter–early spring (Jan–Jun) precipitation (RI = 0.32). Correct classification rates for weighted average models that we derived through the 3 comparisons were between 60 and 70%, suggesting the variables adequately differentiated between plot types. However, high model selection uncertainty (i.e., the total number of models included in the sets of AICc-selected models) suggested that nest site selection and nesting success may be influenced by factors not considered in the modeling process. Management strategies that protect dense sagebrush stands and enhance residual grass cover and height within those stands should be used to maintain nesting habitat and increase nesting success of greater sage-grouse.