Geology topics

Lee J. Foster

Publications and source records attributed to Lee J. Foster.

8 recordsLinked to original sources

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↗

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

Synthesizing and analyzing long-term monitoring data: A greater sage-grouse case study

Long-term monitoring of natural resources is imperative for increasing the understanding of ecosystem processes, services, and how to manage those ecosystems to maintain or improve function. Challenges with using these data may occur because methods of monitoring changed over time, multiple organizations collect and manage data differently, and monetary resources fluctuate, affecting many aspects of data. Because many species respond to changes in habitat conditions and predator-prey relationships across different spatial scales that span management boundaries, greater efforts for collaborating are essential. We demonstrate the challenges and methods for standardizing greater sage-grouse ( Centrocercus urophasianus ) long-term monitoring data across the species range in the western United States to inform population modeling needs identified by the Western Association of Fish and Wildlife Agencies. We used automated and repeatable methods of standardizing data via custom open-source software ( grsg_lekdb ) to improve the scientific integrity of future sage-grouse population assessments within and among states. Data standardization included reconciling uses of different terminology and expunging unusable data, resulting in the removal of 26% of data records due to database insertion errors and modifications to >1 million values to correct formatting and typing errors. Our approaches maximized the inclusion of usable data and identified data that could inform detection probabilities, population trends, and monitoring guidelines. Using sage-grouse databases as an example, we identified the importance of data management and how quality assurance and quality control measures can improve the usefulness of these data for future research needs. Our methods of using informatics and concluding recommendations can support similar endeavors of flora and fauna monitoring programs, whether those efforts are to use existing data or support new monitoring programs.

Ecological Informatics↗

USGS2020

Broad-scale impacts of an invasive native predator on a sensitive native prey species within the shifting avian community of the North American Great Basin

Human enterprise has modified ecosystem processes through direct and indirect alteration of native predators’ distribution and abundance. For example, human activities subsidize food, water, and shelter availability to generalist predators whose subsequent increased abundance impacts lower trophic-level prey species. The common raven (Corvus corax; hereafter, raven) is an avian predator, native to the northern hemisphere, that can become invasive when subsidized. Raven populations are increasing at unprecedented rates in many regions globally. Information regarding scale of impact and potential ecological thresholds is needed to guide conservation actions aimed at reducing adverse effects on sensitive prey. We conducted a multi-part analysis to investigate broad-scale variation in raven densities and impacts on nesting greater sage-grouse (Centrocercus urophasianus), an indicator species for sagebrush ecosystems in western North America. We estimated raven densities using 16,000 point surveys over 10 years within the Great Basin, USA, and examined associations with anthropogenic and environmental covariates. Average density was 0.54 ravens km-2 (95% CI: 0.42–0.70), with higher densities at lower relative elevations comprising increased agriculture and development. We then used a reduced dataset to estimate the effect of raven density on sage-grouse nest survival (nests = 737). We identified negative impacts to nesting sage-grouse, especially where raven density exceeded ~ 0.40 km-2, a potential ecological threshold. We mapped regions where elevated raven densities were predicted to depress sage-grouse population growth in the absence of compensatory demographic responses from other sage-grouse life-history stages, and found ~ 64% of sage-grouse breeding areas were adversely impacted by high raven density.

California, Idaho, Nevada, Oregon, Utah↗

USGS2018

Potential effects of GPS transmitters on greater sage-grouse survival in a post-fire landscape

Rigorous monitoring and evaluation of wildlife population performance because of management or disturbance often relies upon the handling and marking of animals. Such studies must assume that marking animals does not affect their behavior or demography. We examined survival of greater sage-grouse Centrocercus urophasianus post wildfire in southeastern Oregon, USA. We observed extremely high mortality rates early in the study and questioned if our global positioning systems (GPS) transmitters were negatively affecting survival of adult greater sage-grouse. Thus, in situ we captured and randomly assigned additional grouse to either a GPS or VHF transmitter and examine patterns of mortality and estimated survival to evaluate if there were in fact transmitter effects on this important vital rate. Our results indicated that regardless of instrument type large wildfire had negative effects on monthly survival the first year after the fire. However, point estimates indicated that greater sage-grouse fitted with GPS transmitters had approximately 5% lower annual survival than VHF tagged birds, but although there was relatively large overlap in confidence limits, likely caused by small sample sizes. Further research is needed to disentangle potential confounding effects of GPS transmitters on survival impacts of grouse in association with large disturbance.

Oregon↗

USGS2018

Greater sage-grouse vital rates after wildfire

Greater sage-grouse ( Centrocercus urophasianus ) have been subject to long-term and continuing declines in population and habitat since European settlement of western North America. Increased wildfire activity constitutes a primary threat to the species in western portions of their range, with documented declines in wildfire-affected populations. Following a 187,000-ha wildfire in southeastern Oregon and northern Nevada, USA, we used global positioning system (GPS) telemetry to monitor nest initiation, nest survival, nesting habitat, and adult survival of female sage-grouse during 2013 and 2014. We used known-fate models in Program MARK to estimate daily nest survival and monthly adult survival in relation to temporal patterns, physiological characteristics of females, and habitat and land-cover characteristics. We assessed habitat characteristics using geographic information system (GIS)-derived measures of post-fire habitat condition and land cover. Nest initiation rate following the fire was comparable to that observed in unaltered habitat. We observed nesting rates of 90% and 100% during 2013 and 2014, respectively, and renesting rates of 23% and 57% during the same years. Daily nest survival was consistently low in comparison to rates observed in concurrent studies in the region, for first nests during both years, and for second nests during 2013, but survival markedly increased for second nests during 2014. Sage-grouse generally did not leave the fire perimeter to nest, with 64% and 73% of nests located in the fire boundary during 2013 and 2014, respectively. Approximately 27% of nests were located in burned habitat during 2013, and 20% of nests in 2014 were located in burned habitat. Adult survival varied by month, and although patterns of monthly survival were similar between years, monthly survival rates were significantly reduced from the beginning of the study through the end of the first post-fire growing season. Our results indicate that sage-grouse continue to use fire-affected habitat in the years immediately following wildfire and sage-grouse experienced lower nest survival and adult female survival than other populations during the same period.

Oregon↗

USGS2018

Broad‐scale occurrence of a subsidized avian predator: reducing impacts of ravens on sage‐grouse and other sensitive prey

Expanding human enterprise across remote environments impacts numerous wildlife species. Anthropogenic resources provide subsidies for generalist predators that can lead to cascading effects on prey species at lower trophic levels. A fundamental challenge for applied ecologists is to disentangle natural and anthropogenic influences on species occurrence, and subsequently develop spatially explicit models to help inform management and conservation decisions. Using Bayesian hierarchical occupancy models, we mapped the broad‐scale occurrence of common ravens Corvus corax as a function of natural and anthropogenic landscape covariates using >15,000 point count surveys performed during 2007–2016 within the Great Basin region, USA. Raven abundance and distribution is substantially increasing across the American west due to unintended anthropogenic resource subsidies. Importantly, ravens prey on eggs and chicks of numerous species including greater sage‐grouse Centrocercus urophasianus , an indicator species whose decline is at the centre of national conservation strategies and land use policies.Anthropogenic factors that contributed to greater raven occurrence were: increased road density, presence of transmission lines, agricultural activity, and presence of roadside rest areas. Natural landscape characteristics included lower elevations with greener vegetation (NDVI), greater stream and habitat edge densities, and lower percentages of big sagebrush A. tridentata spp . Interactions between anthropogenic sources of nesting substrate and food subsidies suggested that raven occurrence increased multiplicatively when these resource subsidies co‐occurred. Overall, the average probability of raven occurrence estimated within sagebrush ecosystems of the study area was ~0.83. Synthesis and applications . We demonstrate how anthropogenic factors can be disentangled from natural effects when making spatially‐explicit predictions of subsidized predators occurring across expansive landscapes. This approach can guide management decisions where subsidized predators overlap sensitive prey habitats. For example, we identify areas where elevated raven occurrence coincides with breeding sage‐grouse concentration areas and appears to be largely driven by anthropogenic factors. Management applications could focus on reducing raven access to anthropogenic subsidies in these areas, while prioritizing habitat improvements for sage‐grouse elsewhere. Our approach is applicable to other species where widespread survey data are available.

Journal of Applied Ecology↗

USGS2018

Greater sage-grouse science (2015–17)—Synthesis and potential management implications

Executive Summary The greater sage-grouse ( Centrocercus urophasianus ; hereafter called “sage-grouse”), a species that requires sagebrush (Artemisia spp.), has experienced range-wide declines in its distribution and abundance. These declines have prompted substantial research and management investments to improve the understanding of sage-grouse and its habitats and reverse declines in distribution and population numbers. Over the past two decades, the U.S. Fish and Wildlife Service (USFWS) has responded to eight petitions to list the sage-grouse under the Endangered Species Act of 1973, with the completion of the most recent listing determination in September 2015. At that time, the USFWS determined that the sage-grouse did not warrant a listing, primarily because of the large scale science-based conservation and planning efforts completed or started by Federal, State, local agencies, private landowners, and other entities across the range. The planning efforts culminated in the development of the 2015 Bureau of Land Management (BLM) and U.S. Forest Service Land Use Plan Amendments, which provided regulatory certainty and commitment from Federal land-management agencies to limit, mitigate, and track anthropogenic disturbance and implement other sage-grouse conservation measures. After these policy decisions, the scientific community has continued to refine and expand the knowledge available to inform implementation of management actions, increase the efficiency and effectiveness of those actions, and continue developing an overall understanding of sage-grouse populations, habitat requirements, and their response to human activity and other habitat changes. The development of science has been driven by multiple prioritization documents including the “Greater Sage-Grouse National Research Strategy” (Hanser and Manier, 2013) and, most recently, the “Integrated Rangeland Fire Management Strategy Actionable Science Plan” (Integrated Rangeland Fire Management Strategy Actionable Science Plan Team, 2016). In October 2017, after a review of the 2015 Federal plans relative to State sage-grouse plans, in accordance with Secretarial Order 3353, the BLM issued a notice of intent to consider whether to amend some, all, or none of the 2015 land use plans. At that time, the BLM requested the U.S. Geological Survey (USGS) to inform this effort through the development of an annotated bibliography of sage-grouse science published since January 2015 and a report that synthesized and outlined the potential management implications of this new science. Development of the annotated bibliography resulted in the identification and summarization of 169 peer-reviewed scientific publications and reports. The USGS then convened an interagency team (hereafter referred to as the “team”) to develop this report that focuses on the primary topics of importance to the ongoing management of sage-grouse and their habitats. The team developed this report in a three-step process. First, the team identified six primary topic areas for discussion based on the members’ collective knowledge regarding sage-grouse, their habitats, and threats to either or both. Second, the team reviewed all the material in the “Annotated Bibliography of Scientific Research on Greater Sage-Grouse Published since January 2015” to identify the science that addressed the topics. Third, team members discussed the science related to each topic, evaluated the consistency of the science with existing knowledge before 2015, and summarized the potential management implications of this science. The six primary topics identified by the team were: Multiscale habitat suitability and mapping tools Discrete anthropogenic activities Diffuse activities Fire and invasive species Restoration effectiveness Population estimation and genetics

Open-File Report↗