Geology topics

Christian A. Hagen

Publications and source records attributed to Christian A. Hagen.

At least 19 recordsLinked to original sources

USGS2025

Greater sage-grouse seasonal habitat associations: A review and considerations for interpretation and management applications

Habitat features needed by wildlife can change in composition throughout the year, particularly in temperate ecosystems, leading to distinct seasonal spatial-use patterns. Studies of species-habitat associations therefore often focus on understanding relationships within discrete seasonal periods with common goals of prediction (e.g., habitat mapping) and inference (e.g., interpreting model coefficients). Across the range of the greater sage-grouse ( Centrocercus urophasianus ) of western North America, the increasing use of high-frequency tracking devices has led to a surge in habitat association studies covering multiple temporal periods and spatial extents. We reviewed the literature for seasonal habitat association studies corresponding to the second and third orders of selection (Johnson 1980). Our objectives were to summarize the methodological approaches used to estimate habitat associations to aid understanding in cross-study comparisons and identify common habitat features reported as selected or avoided within different seasonal periods. We reviewed 71 second- and third-order studies published from 2007–2023 that evaluated covariates collected in a geographic information system (GIS) and modeled probability of selection or intensity of use. The most common study design evaluated a single level of selection (third-order) and was multi-scale (i.e., covariates were measured at varying spatial grains). The most common model approach estimated habitat associations using resource selection functions (RSFs) fit with logistic regression. Studies mostly focused on the breeding periods and winter, but all seasons throughout the annual cycle were covered. There was clear support for selection of sagebrush and avoidance of trees and rugged terrain across seasons, and strong selection of mesic conditions in summer. However, habitat associations for most covariates were mixed, with proportionally equivalent selection and avoidance reported, even within the same seasons. Different factors hampered cross-study comparisons, including variation in study design, but additional contributors likely included important context-dependent habitat associations, such as functional responses to changing habitat availability. We suggest collaborative studies leveraging multiple datasets can help improve seasonal habitat inference by removing the effects of variable study designs.

Journal of Wildlife Management↗

USGS2024

Living on the edge: Identifying demographic bottlenecks in an isolated sage-grouse population

The greater sage-grouse ( Centrocercus urophasianus : hereafter sage-grouse) population in Modoc County California is geographically isolated and contains a single lek (from 56 leks in the 1940s), despite significant efforts to increase the population through translocations and habitat improvement. Repeated wildfire within the landscape has led to an increase in invasive annual grasses and a decrease in sagebrush ( Artemisia sp.) cover in important nesting and brood-rearing habitat. We estimated survival for adult females, nests, and chicks and assessed biotic characteristics that may influence these survival estimates to identify factors that may be limiting population growth. We monitored 37 female sage-grouse marked with GPS PTTS, 39 nests, and 8 broods for 3 years (2019–2021). We measured vegetation characteristics for nests at the microsite and landscape scale to evaluate effects on daily nest survival (DNS). We used survival rates from all life stages to parameterize matrix models and estimate population growth rate. Mean nest success over 3 years was 29% (95% CI: 17.1–44.8) across a 29-day incubation period and DNS declined as the proportion of both medusahead Taeniatherum caput-medusae and Japanese brome Bromus japonicus around the nest increased. Across all three years, mean chick survival across a 54-day period was 44% (95% CI: 0.9–72.3) and mean annual survival for adult females was 29% (95% CI: 17.8–43.7). Our estimated vital rates were 45–55% lower than distribution-wide estimates and the projected population growth rate was strongly declining (0.411, 95% CI: 0.30–0.52). Our results suggested recent cover changes associated with wildfire on the study area may have had a detrimental effect on this population across all life stages, and if attention is not given to preventing the transition from sagebrush communities into invasive grasslands, this population and others in degraded landscapes may not persist.

California↗

USGS2024

Evaluating satellite-transmitter backpack-harness effects on greater sage-grouse survival and device retention in the Great Basin

Wildlife tracking studies have become ubiquitous in ecology and now provide previously unobtainable data regarding individual movement, vital rates, and population demographics. However, tracking devices can potentially reduce survival of study subjects, generating biases in the vital rates they seek to measure. Previous studies have found that greater sage-grouse ( Centrocercus urophasianus ) fitted with Global Positioning System (GPS) tracking devices may experience reduced survival, relative to those tracked with traditional radio transmitters, and have documented skin abrasions and lacerations associated with typical backpack-style GPS harnesses. We implemented an experimental study comparing survival and harness retention between 2 different backpack-style GPS transmitter harnesses. We captured female sage-grouse at 3 study sites in the northwest Great Basin of Oregon, Nevada, and California during 2019–2021. We fit each individual, following previously published recommendations, with either a standard backpack harness or a modified harness hypothesized to reduce skin abrasion and laceration. We used known-fate models in Program MARK to model variation in survival and harness retention separately as a function of harness type, year, age, a linear effect of time, and the ratio of the device to individual body mass. Neither survival nor retention varied systematically by harness type, however retention decreased as a function of body mass ratio. We echo previous recommendations for standardized harness attachment protocols and studies designed to isolate and test potential mechanisms by which tracking devices and attachment methods might affect survival and well-being of sage-grouse and other tracked species.

California Nevada, Oregon↗

USGS2024

Melded integrated population models

Integrated population models provide a framework for assimilating multiple datasets to understand population dynamics. Understanding drivers of demography is key to improving wildlife management, and integrated population models have informed conservation practices for many species of conservation concern. Motivated by multiple surveys of lesser prairie-chicken ( Tympanuchus pallidicinctus ), we developed a flexible integrated population modeling framework for assimilating demographic data with multiple surveys of abundance. Measurements of abundance are derived from aerial and ground surveys that vary in their observational uncertainty, sampling design, temporal coverage, and survey effort. Our proposed integrated population model draws from the strengths of each survey and prevents their sampling biases from compromising inference. We facilitate posterior inference for our integrated population model using chained Markov melding, which induces the joint distribution for all data sources by linking inference across several submodels. Using Markov melding, we extend the modeling framework previously proposed for analyzing the individual data sources while still obtaining joint Bayesian inference. We fit the melded model with a multistage Markov chain Monte Carlo algorithm that decreases run time and improves mixing. We assimilate data from several state and federal wildlife agencies and over a dozen independent researchers to infer lesser prairie-chicken abundance and vital rates across its entire range over the last 18 years. Supplementary materials accompanying this paper appear online.

Colorado, Kansas, New Mexico, Oklahoma, Texas↗

USGS2024

Recovery of working grasslands following a megafire in the southern mixed-grass prairie

While fire is a necessary ecological driver for grassland systems, Great Plains grasslands have undergone extensive land use change following European settlement (conversion, fragmentation, fire suppression, intensive grazing, etc.). Recent studies have documented the benefits of re-introducing fire to grasslands, but work has largely focused on small-scale, low-intensity fire, often at a pasture scale (i.e., prescribed fire). Over the last 30–40 years, the size and frequency of wildfires in the Great Plains has increased due to long-term fire suppression, woody encroachment, and climate change, resulting in megafires (wildfire >40,000 ha). While there is a wealth of information regarding effects of prescribed fire on Great Plains grasslands, knowledge of how large megafire events affect modern, fragmented working grasslands (i.e., grazed grasslands) is lacking and needed in the face of increasing megafire activity. To assess grassland response and recovery following a 2017 megafire (~254,000 ha), we compared vegetation characteristics pre- (2014–2015) and post-fire (2018–2019) in the mixed-grass prairie of Kansas, USA. We examined linkages between vegetation characteristics and a metric of burn severity (differenced normalized burn ratio [dNBR]) and evaluated megafire effects on limiting reproductive habitat for a declining grassland species, the lesser prairie-chicken ( Tympanuchus pallidicinctus ). One-year post-fire, we documented increased bare ground (+59%) and decreased visual obstruction (−39%), litter depth (−31%), and forb cover (−35%). Decreased visual obstruction and increased bare ground led to an 81% decrease of lesser prairie-chicken nest habitat in the first-year post-fire, but grassland structure, functional group cover, and available nest habitat largely recovered 2.5 years post-fire. Recovery to pre-fire conditions 2.5 years post-fire was primarily due to elevated growing season precipitation received in the years following the fire (>700 mm/year). Percent cover of grass (β = 0.38) and bare ground (β = −0.36) exhibited the strongest relationships with burn severity pre-fire, but overall grassland structure and functional group cover were not strongly influenced dNBR burn severity post-fire. While our results suggested that recovering grasslands were more homogenous due to the large size of megafire, working grasslands in the mixed-grass prairie appeared largely resilient to the effects of megafire.

Kansas, Oklahoma↗

USGS2022

Demographic effects of a megafire on a declining prairie grouse in the mixed-grass prairie

Recent studies have documented benefits of small, prescribed fire and wildfire for grassland-dependent wildlife, such as lesser prairie-chickens ( Tympanuchus pallidicintus ), but wildlife demographic response to the scale and intensity of megafire (wildfire >40,000 ha) in modern, fragmented grasslands remains unknown. Limited available grassland habitat makes it imperative to understand if increasing frequency of megafires could further reduce already declining lesser prairie-chicken populations, or if historical evolutionary interactions with fire make lesser prairie-chickens resilient. To evaluate lesser prairie-chicken demographic response to megafires, we compared lek counts, nest density, and survival rates of adults, nests, and chicks before (2014–2016) and after (2018–2020) a 2017 megafire in the mixed-grass prairie of Kansas, USA (Starbuck fire ~254,000 ha). There was a 67% decline in attending males on leks post-fire and a 57% decline in occupied leks post-fire. Despite population declines as indicated by lek counts, adult female breeding season survival ( Ŝ ) was similar pre- ( Ŝ = 0.65 ± 0.08 [SE]) and post-fire (0.61 ± 0.08), as was chick survival (pre-fire: 0.23 ± 0.07; post-fire: 0.27 ± 0.11). Nest survival appeared lower post-fire (pre-fire: 0.38 ± 0.06; post-fire: 0.20 ± 0.06), but did not differ at the 95% confidence interval. Nest density of marked females declined 73% in areas burned by megafire. Although lesser prairie-chickens persisted in the study area and we documented minimal effects on most demographic rates, reduced lesser prairie-chicken abundance and reproductive output suggests full recovery may take >3 years. Increased propensity for megafire resulting from suppression of smaller fires, compounded by climate change and woody encroachment, may impose a short-term (3–5 year) threat to already declining lesser prairie-chicken populations.

Kansas, Oklahoma↗

USGS2022

Temporal mismatch in space use by a sagebrush obligate species after large-scale wildfire

The increase in size and frequency of wildfires in sagebrush steppe ecosystems has significant impacts on sagebrush obligate species. We modeled seasonal habitat use by female greater sage-grouse ( Centrocercus urophasianus ) in the Trout Creek Mountains of Oregon and Nevada, USA, to identify landscape characteristics that influenced sage-grouse habitat selection and to create predictive surfaces of seasonal use 1 and 7 years postfire. We developed three resource selection function models using GPS location data from 2013 to 2019 for three biologically distinct seasons (breeding, n = 149 individuals: 8 March–12 June; summer, n = 140 individuals: 13 June–20 October; and winter, n = 94 individuals: 21 October–7 March). For all seasons, by the fourth or fifth year postfire, sage-grouse selected for unburned patches more than all other burn severity patches and the use of unburned areas in comparison with burned areas increased through time. During the breeding season, sage-grouse selected for low-sagebrush ( Artemisia arbuscula )-dominated ecosystems and areas with low biomass (normalized difference vegetation index). During summer, sage-grouse selected for areas with higher annual and perennial grasses and forb cover, and areas that had higher biomass. During winter, sage-grouse selected for areas of intact sagebrush on less rugged terrain. For the winter and breeding season, there was a positive linear relationship between annual grasses and forb cover through time. Seven years postfire (2019), the area predicted to have a high probability of use in each seasonal range decreased (breeding: 16.4%; summer: 12.2%; and winter: 4.2%), while the area predicted to have low or low-medium probability of use increased (breeding: 14.5%; summer: 22.5%; and winter: 22.8%) when compared to the first year following the wildfire (2013). Our results demonstrated a 4- to 5-year time lag before female sage-grouse adapted to a disturbed landscape began avoiding burned areas more than intact, unburned habitats. This mismatch in ecological response may imply declines in habitat availability for sage-grouse and may destabilize population vital rates. Spatially explicit models can aid in identifying priority areas for restoration efforts and conservation actions to mitigate the impacts of future disturbances.

Nevada, Oregon↗

USGS2022

Trends of lesser prairie-chicken habitat extent and distribution on the Southern High Plains

The lesser prairie-chicken ( Tympanuchus pallidicinctus ) is a species of prairie grouse that occupies grassland ecosystems in the Southern and Central High Plains of the Great Plains. Reduced abundance and occupied ranges have led to increased conservation efforts throughout the species’ range. Habitat loss is considered the predominant cause of these declines. In the Southern High Plains of Texas and New Mexico, lesser prairie-chicken habitat corresponds to the Sand Shinnery Oak Prairie Ecoregion, which is comprised of a mixture of sand shinnery oak ( Quercus havardii) -dominated grasslands, sand sagebrush ( Artemisia filifolia )-dominated grasslands, and mixed grasslands. In sand shinnery oak–grassland communities, conversion to row-crop agriculture, continuous unmanaged livestock grazing, restriction of natural fire, invasive plant species (e.g., mesquite ( Prosopis spp. )), extensive use of herbicides, energy development, and a variety of other factors have also negatively affected ecosystem extent and function. We integrated historical maps and remote sensing-derived information to measure trends in the extent and geographical distribution of sand shinnery oak prairies in eastern New Mexico and northwest Texas. Potential lesser prairie-chicken habitat was reduced by 56% from a potential of 43,258 km 2 to 18,908 km 2 in ~115 years (since pre-settlement). Our assessment indicated both mixed grasslands and sand shinnery oak-dominated grasslands were transformed from large parcels of existing vegetation communities to urban settlements, row crops, roads, and industrial land uses by the 1970s. Currently, potential habitat is highly fragmented and restricted to isolated locations in Texas and New Mexico, with an increasing dominance in mixed grasslands, especially in the southeastern portion of the lesser prairie-chicken range. Sand shinnery oak-dominated grasslands have been declining rapidly, from 69% of its potential extent in 1985, 65% in 1995, 54% in 2005, to 42% in 2015. Mixed grasslands drastically declined to 50% of its potential distribution by 1985. Since then, it has been stable until the 2005–2015 period when it declined to 45% of its potential extent. Based on the 2015 assessment, the current potential habitat for lesser prairie chicken is estimated at 18,908 km 2 (1,890,800 ha or 4.6 million acres), where 13,126 km 2 corresponds to mixed grasslands and 5782 km 2 corresponds to sand shinnery oak-dominated grasslands.

New Mexico, Texas↗

USGS2022

Effects of megafire on woody species in the mixed-grass prairie

Lack of fire in contemporary grasslands has contributed to the invasion of woody plants that can survive low-intensity fire upon maturity, but knowledge of the effects of megafires (>40,000 ha) on grassland tree mortality is limited. We used remote sensing and ground surveys to estimate tree canopy cover change and rates of top-kill and mortality of woody species in the mixed-grass prairie following megafire. After megafire, we detected 63% tree canopy cover loss, 17 ± 4% (mean ± SD) of woodland trees were dead, and 56 ± 5% of tree species were top-killed and resprouted. We conclude that further postfire management (e.g., targeted herbicide, mechanical removal) may be required to limit woody encroachment following megafire.

Kansas↗

USGS2021

Acute and lagged fitness consequences for a sagebrush obligate in a post mega-wildfire landscape

Species responses to disturbance influence their extinction risks. Greater sage- grouse ( Centrocercus urophasianus ) are bioindicators of sagebrush ecosystem health and the loss of sagebrush ( Artemisia spp.) due to wildfire, can cause long- term declines in sage- grouse populations and other sagebrush obligate species. We examined the de - mographic response of a greater sage- grouse population following a mega- wildfire using stochastic age- structured female- based matrix models over 6 years (2013– 2018). Notably, chick survival (range = 0.18– 0.38) and female survival (yearling range: 0.20– 0.68; adult range: 0.27– 0.75) were low compared to values reported for greater sage- grouse in other parts of their distribution. Greater sage- grouse displayed vari - ation in demographic tactics after the fire; however, adult female survival explained most of the variation in λ during each year, which reflected a declining population in 3 of 6 years with more uncertainty observed in 2015 when populations may have been increasing, and 2017 and 2018, when populations may have been declining. The continued annual population decline observed since 2016 suggested there were ad - ditional strong environmental impacts that may have been compounded by the fire effects, prolonging recovery of greater sage- grouse. Our results support others that reported negative effects to greater sage- grouse demographics from broad- scale fire and provide a baseline for understanding how this species responds to loss of sage - brush cover based on their life history strategy.

Nevada, Oregon↗

USGS2021

Ecological disturbance through patch-burn grazing influences lesser prairie-chicken space use

Across portions of the western Great Plains in North America, natural fire has been removed from grassland ecosystems, decreasing vegetation heterogeneity and allowing woody encroachment. The loss of fire has implications for grassland species requiring diverse vegetation patches and structure or patches that have limited occurrence in the absence of fire. The lesser prairie-chicken ( Tympanuchus pallidicinctus ) is a declining species of prairie-grouse that requires heterogeneous grasslands throughout its life history and fire has been removed from much of its occupied range. Patch-burn grazing is a management strategy that re-establishes the fire-grazing interaction to a grassland system, increasing heterogeneity in vegetation structure and composition. We evaluated the effects of patch-burn grazing on lesser prairie-chicken space use, habitat features, and vegetation selection during a 4-year field study from 2014–2017. Female lesser prairie-chickens selected 1- and 2-year post-fire patches during the lekking season, ≥4-year post-fire patches during the nesting season, and year-of-fire and 1-year post-fire patches during post-nesting and nonbreeding seasons. Vegetation selection during the lekking season was not similar to available vegetation in selected patches, suggesting that lesser prairie-chickens cue in on other factors during the lekking season. During the nesting season, females selected nest sites with greater visual obstruction, which was available in ≥4-year post-fire patches; during the post-nesting season, females selected sites with 15–25% bare ground, which was available in the year-of-fire, 1-year post-fire, and 2-year post-fire patches; and during the nonbreeding season they selected sites with lower visual obstruction, available in the year-of-fire and 1-year post-fire patches. Because lesser prairie-chickens selected all available time-since-fire patches during their life history, patch-burn grazing may be a viable management tool to restore and maintain lesser prairie-chicken habitat on the landscape. © 2021 The Wildlife Society.

Kansas↗

USGS2021

Nest microclimates of Greater Sage-Grouse in a post-megafire landscape: does selection equate to success?

Temperature at fine spatial scales is an important driver of nest site selection for many avian species during the breeding season and can influence nest success. Sagebrush ( Artemisia spp. ) communities have areas with high levels of vegetation heterogeneity and high thermal variation; however, fire removes vegetation that provides protection from predators and extreme environmental conditions. To examine the influence of microclimates on Greater Sage-Grouse ( Centrocercus urophasianus ) nest site selection and nest success in a fire affected landscape, we measured black bulb temperature (Tbb) and vegetation attributes (e.g. visual obstruction) at 3 spatial scales (i.e. nest bowl, microsite, and landscape) in unburned and burned areas. Nest bowls exhibited greater buffering of Tbb than both nearby microsites and the broader landscape. Notably, nest bowls were warmer in cold temperatures, and cooler in hot temperatures, than nearby microsites and the broader landscape, regardless of burn stage. Nest survival was higher for nests in unburned areas compared to nests in burned areas (unburned NS = 0.43, 95% CI: 0.33 to 0.54; burned NS = 0.24, 95% CI: 0.10 to 0.46). Amount of bare ground was negatively associated with nest survival, but effects diminished as the amount of bare ground reached very low levels. Shrub height and visual obstruction were positively associated with nest survival during the entire study period whereas, minimum Tbb had a weaker effect. Our findings demonstrate that thermoregulatory selection by Greater Sage-Grouse at nest sites had marginal effects on their nest survival. However, given that increases in vegetation structure (e.g. shrub height) provides thermal refuge and increases nest survival, vegetation remnants or regeneration in a post-fire landscape could be critical to Greater Sage-Grouse nesting ecology.

Oregon, Nevada↗

USGS2021

Using grazing to manage herbaceous structure for a heterogeneity-dependent bird

Grazing management recommendations often sacrifice the intrinsic heterogeneity of grasslands by prescribing uniform grazing distributions through smaller pastures, increased stocking densities, and reduced grazing periods. The lack of patch-burn grazing in semi-arid landscapes of the western Great Plains in North America requires alternative grazing management strategies to create and maintain heterogeneity of habitat structure (e.g., animal unit distribution, pasture configuration), but knowledge of their effects on grassland fauna is limited. The lesser prairie-chicken ( Tympanuchus pallidicinctus ), an imperiled, grassland-obligate, native to the southern Great Plains, is an excellent candidate for investigating effects of heterogeneity-based grazing management strategies because it requires diverse microhabitats among life-history stages in a semi-arid landscape. We evaluated influences of heterogeneity-based grazing management strategies on vegetation structure, habitat selection, and nest and adult survival of lesser prairie-chickens in western Kansas, USA. We captured and monitored 116 female lesser prairie-chickens marked with very high frequency (VHF) or global positioning system (GPS) transmitters and collected landscape-scale vegetation and grazing data during 2013–2015. Vegetation structure heterogeneity increased at stocking densities ≤0.26 animal units/ha, where use by nonbreeding female lesser prairie-chickens also increased. Probability of use for nonbreeding lesser prairie-chickens peaked at values of cattle forage use values near 37% and steadily decreased with use ≥40%. Probability of use was positively affected by increasing pasture area. A quadratic relationship existed between growing season deferment and probability of use. We found that 70% of nests were located in grazing units in which grazing pressure was <0.8 animal unit months/ha. Daily nest survival was negatively correlated with grazing pressure. We found no relationship between adult survival and grazing management strategies. Conservation in grasslands expressing flora community composition appropriate for lesser prairie-chickens can maintain appropriate habitat structure heterogeneity through the use of low to moderate stocking densities (<0.26 animal units/ha), greater pasture areas, and site-appropriate deferment periods. Alternative grazing management strategies (e.g., rest-rotation, season-long rest) may be appropriate in grasslands requiring greater heterogeneity or during intensive drought. Grazing management favoring habitat heterogeneity instead of uniform grazing distributions will likely be more conducive for preserving lesser prairie-chicken populations and grassland biodiversity.

Kansas↗

USGS2021

Breeding season space use by lesser prairie-chickens (Tympanuchus Pallidicinctus) varies among ecoregions and breeding stages

Large-scale declines of grassland ecosystems in the conterminous United States since European settlement have led to substantial loss and fragmentation of lesser prairie-chicken ( Tympanuchus pallidicinctus ) habitat and decreased their occupied range and population numbers by ∼85%. Breeding season space use is an important component of lesser prairie-chicken conservation, because it could affect both local carrying capacity and population dynamics. Previous estimates of breeding season space use are largely limited to one of the four currently occupied ecoregions, but potential extrinsic drivers of breeding space use, such as landscape fragmentation, vegetation structure and composition, and density of anthropogenic structures, can show large spatial variation. Moreover, habitat needs vary greatly among the lekking/prelaying, nesting, brood-rearing, and postbreeding stages of the breeding season, but space use by female lesser prairie-chickens during these stages remain relatively unclear. We tested whether home range area and daily displacement (the net distance between the first and last location of each day) of female lesser prairie-chickens varied among ecoregions and breeding stages at four study sites in Kansas and Colorado, U.S.A., representing three of the four currently occupied ecoregions. We equipped females with very-high-frequency (VHF) or Global Positioning System (GPS) transmitters, and estimated home range area with kernel density estimators or biased random bridge models, respectively. Across all ecoregions, breeding season home range area averaged 190.4 ha (±19.1 ha se ) for birds with VHF and 283.6 ha (±23.1 ha) for birds with GPS transmitters, whereas daily displacement averaged 374.8 m (±14.3 m). Average home range area and daily displacement of bird with GPS transmitters were greater in the Short-Grass Prairie/ Conservation Reserve Program Mosaic and Sand Sagebrush Prairie Ecoregions compared to sites in the Mixed-Grass Prairie Ecoregion. Home range area and daily displacement were greatest during lekking/prelaying and smallest during the brood-rearing stage, when female movements were restricted by mobility of chicks. Ecoregion- and breeding stage-specific estimates of space use by lesser prairie-chickens will help managers determine the spatial configuration of breeding stage-specific habitat on the landscape. Furthermore, ecoregion- and breeding stage-specific estimates are crucial when estimating the amount of breeding habitat needed for lesser prairie-chicken populations to persist.

Colorado↗

USGS2020

A decision-support tool to prioritize candidate landscapes for lesser prairie-chicken conservation

Context Development of systematic methods for conservation planning has improved effectiveness and efficiency of implementing such plans. The lesser prairie-chicken ( Tympanuchus pallidicinctus ) is a grouse species of conservation concern native to the southwestern Great Plains of the United States. Recent lesser prairie-chicken conservation planning has involved identifying ecologically important areas but has not incorporated economic data into prioritization of areas to target for conservation management. Objectives We used the program Marxan to develop a decision-support tool for managers in Kansas to prioritize tracts for improving lesser prairie-chicken habitat quality and increasing habitat availability. We developed three different conservation scenarios and evaluated the tradeoffs among multiple planning objectives in these scenarios. Methods We incorporated population targets from an existing conservation plan and agricultural economic data to help select land with maximum ecological value and minimum economic productivity to prioritize for lesser prairie-chicken conservation. We compared potential conservation plans and incorporated a post hoc connectivity model to test potential for individuals to travel among habitat patches in these plans during dispersal events. Results We found that different conservation scenarios led to different solutions, though differences varied by ecoregion. Potential solutions for all scenarios contained habitat patches not currently included in existing conservation plans and had high connectivity potential. Conclusions These results provide context for spatial prioritization of lesser prairie-chicken habitat management in Kansas. Application of this approach to species of conservation interest could help managers incorporate socioeconomic factors into planning methods and identify important tracts for conservation currently overlooked by existing planning methods.

Kansas↗

USGS2020

The effects of fire on the thermal environment of sagebrush communities

Thermal heterogeneity provides options for organisms during extreme temperatures that can contribute to their fitness. Sagebrush ( Artemisia spp.) communities exhibit vegetation heterogeneity that creates thermal variation at fine spatial scales. However, fire can change vegetation and thereby variation within the thermal environment of sagebrush communities. To describe spatial and temporal thermal variation of sagebrush communities following wildfire, we measured black bulb temperature ( T bb ) at 144 random points dispersed within unburned and burned communities, for 24-h at each random point. We observed a wide thermal gradient in unburned (−7.3° to 63.3 °C) and burned (−4.6° to 64.8 °C) sagebrush communities. Moreover, unburned and burned sagebrush communities displayed high thermal heterogeneity relative to ambient temperature ( T air ). Notably, T bb varied by 47 °C in both unburned and burned communities when T air was 20 °C. However, fire greatly reduced the buffering capacity and thermal refuge of Wyoming big sagebrush ( A. tridentata wyomingensis ) communities during low and high T air . Furthermore, fire increased T bb in Wyoming big sagebrush and mountain big sagebrush ( A. t. vaseyana ) during the mid-day hours. These results demonstrate how fire changes the thermal environment of big sagebrush communities and the importance of shrub structure which can provide thermal refuge for organisms in burned communities during extreme low and high T air .

Journal of Thermal Biology↗

USGS2019

Factors influencing nesting ecology of lesser prairie-chickens

Lesser prairie-chicken ( Tympanuchus pallidicinctus ) populations have declined since the 1980s. Understanding factors influencing nest-site selection and nest survival are important for conservation and management of lesser prairie-chicken populations. However, >75% of the extant population is in the northern extent of the range where data on breeding season ecology are lacking. We tested factors influencing fine-scale and regional nest-site selection and nest survival across the northern portion of the lesser prairie-chicken range. We trapped and affixed satellite global positioning system and very high frequency transmitters to female lesser prairie-chickens ( n = 307) in south-central and western Kansas and eastern Colorado, USA. We located and monitored 257 lesser prairie-chicken nests from 2013 to 2016. We evaluated nest-site selection and nest survival in comparison to vegetation composition and structure. Overall, nest-site selection in relation to vegetation characteristics was similar across our study area. Lesser prairie-chickens selected nest microsites with 75% visual obstruction 2.0–3.5 dm tall and 95.7% of all nests were in habitat with ≥1 dm and ≤4 dm visual obstruction. Nests were located in areas with 6–8% bare ground, on average, avoiding areas with greater percent cover of bare ground. The type of vegetation present was less important than cover of adequate height. Nest survival was maximized when 75% visual obstruction was 2.0–4.0 dm. Nest survival did not vary spatially or among years and generally increased as intensity of drought decreased throughout the study although not significantly. To provide nesting cover considering yearly variation in drought conditions, it is important to maintain residual cover by managing for structural heterogeneity of vegetation. Managing for structural heterogeneity could be accomplished by maintaining or strategically applying practices of the Conservation Reserve Program, using appropriate fire and grazing disturbances in native working grasslands, and establishing site-specific monitoring of vegetation composition and structure.

Colorado, Kansas↗

USGS2019

Strategic conservation for lesser prairie-chickens among landscapes of varying anthropogenic influence

For millennia grasslands have provided a myriad of ecosystem services and have been coupled with human resource use. The loss of 46% of grasslands worldwide necessitates the need for conservation that is spatially, temporally, and socioeconomically strategic. In the Southern Great Plains of the United States, conversion of native grasslands to cropland, woody encroachment, and establishment of vertical anthropogenic features have made large intact grasslands rare for lesser prairie-chickens ( Tympanuchus pallidicinctus ). However, it remains unclear how the spatial distribution of grasslands and anthropogenic features constrain populations and influence conservation. We estimated the distribution of lesser prairie-chickens using data from individuals marked with GPS transmitters in Kansas and Colorado, USA, and empirically derived relationships with anthropogenic structure densities and grassland composition. Our model suggested decreased probability of use in 2-km radius (12.6 km 2 ) landscapes that had greater than two vertical features, two oil wells, 8 km of county roads, and 0.15 km of major roads or transmission lines. Predicted probability of use was greatest in 5-km radius landscapes that were 77% grassland. Based on our model predictions, ~10% of the current expected lesser prairie-chicken distribution was available as habitat. We used our estimated species distribution to provide spatially explicit prescriptions for CRP enrollment and tree removal in locations most likely to benefit lesser prairie-chickens. Spatially incentivized CRP sign up has the potential to provide 4189 km 2 of additional habitat and strategic application of tree removal has the potential to restore 1154 km 2 . Tree removal and CRP enrollment are conservation tools that can align with landowner goals and are much more likely to be effective on privately owned working lands.

Colorado, Kansas↗