Robert S. Arkle

Robert S. Arkle
United States Geological Survey | USGS · Forest and Rangeland Ecosystem Science Center

About

63
Publications
23,400
Reads
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2,664
Citations
Citations since 2017
30 Research Items
2025 Citations
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Additional affiliations
June 2011 - present
United States Geological Survey
Position
  • Supervisory Ecologist
Description
  • Designing and conducting ecological studies in the Inter-mountain West and Great Basin and publishing results in scientific journals.
June 2007 - June 2011
United States Geological Survey
Position
  • Ecologist
Description
  • Designing and conducting ecological studies in the Inter-mountain West and Great Basin and publishing results in scientific journals.
September 2004 - June 2007
California Polytechnic State University, San Luis Obispo
Position
  • Lecturer
Description
  • Teaching upper division biology and ecology classroom and field-based courses.
Education
September 2004 - June 2007
September 1997 - June 2002
University of California, Irvine
Field of study
  • Biological Sciences, Spc. Ecology & Evolutionary Biology

Publications

Publications (63)
Article
Full-text available
A recurrent challenge in the conservation of wide-ranging, imperiled species is understanding which habitats to protect and whether we are capable of restoring degraded landscapes. For Greater Sage-grouse (Centrocercus urophasianus), a species of conservation concern in the western United States, we approached this problem by developing multi-scale...
Article
Full-text available
Resource managers and scientists need efficient, reliable methods for quantifying vegetation to conduct basic research, evaluate land management actions, and monitor trends in habitat conditions. We examined three methods for quantifying vegetation in 1-ha plots among different plant communities in the northern Great Basin: photography-based grid-p...
Article
Full-text available
Studies have demonstrated negative effects of non-native, predatory fishes on native amphibians, yet it is still unclear why some amphibian populations persist, while others are extirpated, following fish invasion. We examined this question by developing habitat-based occupancy models for the long-toed salamander (Ambystoma macrodactylum) and non-n...
Article
Full-text available
Forest managers use prescribed fire to reduce wildfire risk and to provide resource benefits, yet little information is available on whether prescribed fires can function as ecological surrogates for wildfire in fire-prone landscapes. Information on impacts and benefits of this management tool on stream and riparian ecosystems is particularly lacki...
Article
Full-text available
Stream ecosystems harbor many secretive and imperiled species, and studies of vertebrates in these systems face the challenges of relatively low detection rates and high costs. Environmental DNA (eDNA) has recently been confirmed as a sensitive and efficient tool for documenting aquatic vertebrates in wetlands and in a large river and canal system....
Article
Full-text available
For nearly 40 years, the Conservation Reserve Program (CRP) has implemented practices to reduce soil erosion, improve water quality, and provide habitat for wildlife and pollinators on highly erodible cropland in the United States. However, an approximately 40,470 ha (10 million acres) decline in enrolled CRP land over the last decade has greatly r...
Article
Full-text available
Improving post‐wildfire restoration of foundational plant species is crucial for conserving imperiled ecosystems. We sought to better understand the initial establishment of sagebrush (Artemisia sp.), a foundational shrubland species over a vast area of western North America, in the first 1–2 years post‐wildfire, a critical time period for populati...
Article
Full-text available
Although bull trout (Salvelinus confluentus) and tailed frogs (Ascaphus montanus) have co-existed in forested Pacific Northwest streams for millennia, these iconic cold-water specialists are experiencing rapid environmental change caused by a warming climate and enhanced wildfire activity. Our goal was to inform future conservation by examining the...
Article
Full-text available
Amphibian populations are sensitive to environmental temperatures and moisture, which vary with local weather conditions and may reach new norms and extremes as contemporary climate change progresses. Using long-term (11–16 years) mark-recapture data from 10 populations of the Columbia spotted frog (Rana luteiventris) from across its U.S. range, we...
Article
Full-text available
The U.S. federal government has recently committed to the difficult task of slowing and managing the invasive grass‐fire cycle in sagebrush steppe, where property, livelihoods, and entire ecosystems are at risk. To safely manage this crisis, the government recently proposed to construct about 17,700 km of fuel breaks and millions of hectares of fue...
Article
Full-text available
The U.S. Department of Agriculture’s Conservation Reserve Program (CRP) is one of the largest private lands conservation programs in the United States, establishing perennial vegetation on environmentally sensitive lands formerly in agricultural production. Over its 35 year existence, the CRP has evolved to include diverse conservation practices (C...
Article
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A lack of information regarding which ecological factors influence restoration success or failure has hindered scientifically based restoration decision-making. We focus on one headwater site to examine factors influencing divergent ecological outcomes of two post-mining stream restoration projects designed to improve instream conditions following...
Article
Full-text available
Abstract A better understanding of seed movement in plant community dynamics is needed, especially in light of disturbance‐driven changes and investments into restoring degraded plant communities. A primary agent of change within the sagebrush‐steppe is wildfire and invasion by non‐native forbs and grasses, primarily cheatgrass (Bromus tectorum). O...
Technical Report
The greater sage-grouse (Centrocercus urophasianus; hereafter GRSG) has been a focus of scientific investigation and management action for the past two decades. The 2015 U.S. Fish and Wildlife Service listing determination of “not warranted” was in part due to a large-scale collaborative effort to develop strategies to conserve GRSG populations and...
Technical Report
Full-text available
The greater sage-grouse (Centrocercus urophasianus; hereafter GRSG) has been a focus of scientific investigation and management action for the past two decades. The 2015 U.S. Fish and Wildlife Service listing determination of “not warranted” was in part due to a large-scale collaborative effort to develop strategies to conserve GRSG populations and...
Article
Full-text available
Wildfires change plant community structure and impact wildlife habitat and population dynamics. Recent wildfire‐induced losses of big sagebrush (Artemisia tridentata ) in North American shrublands are outpacing natural recovery and leading to substantial losses in habitat for sagebrush‐obligate species such as Greater Sage‐grouse. Managers are cons...
Article
The effects of extreme concentrations of toxic metalloids, such as arsenic (As) and antimony (Sb), on larval amphibians are not well understood. We sampled Western Toad tadpoles (Anaxyrus boreas) living in As- and Sb-contaminated wetlands throughout their development. Although the tadpoles completed metamorphosis, they accumulated among the highest...
Article
Full-text available
Ecological droughts are deficits in soil-water availability that induce threshold-like ecosystem responses, such as causing altered or degraded plant-community conditions, which can be exceedingly difficult to reverse. However, 'ecological drought' can be difficult to define, let alone to quantify, especially at spatial and temporal scales relevant...
Article
Full-text available
In conservation paradigms, management actions for umbrella species also benefit co‐occurring species because of overlapping ranges and similar habitat associations. The greater sage‐grouse (Centrocercus urophasianus) is an umbrella species because it occurs across vast sagebrush ecosystems of western North America and is the recipient of extensive...
Article
The greater sage-grouse (Centrocercus urophasianus; hereafter GRSG) has been a focus of scientific investigation and management action for the past two decades. The 2015 U.S. Fish and Wildlife Service listing determination of “not warranted” was in part due to a large-scale collaborative effort to develop strategies to conserve GRSG populations and...
Data
These data were collected between 1996 and 2018 to represent the on the ground burn severity as estimated by the Composite Burn Index (CBI). These data can be regressed against satellite estimates of burn severity (e.g. Landsat Normalized Burn Ratio) to develop regression equations.
Article
Full-text available
The apparent failure of ecosystems to recover from increasingly widespread disturbance is a global concern. Despite growing focus on factors inhibiting resilience and restoration, we still know very little about how demographic and population processes influence recovery. Using inverse and forward demographic modelling of 531 post‐fire sagebrush po...
Article
Full-text available
Reestablishing shrub canopy cover after disturbance in semi‐arid ecosystems, such as sagebrush steppe, is essential to provide wildlife habitat and restore ecosystem functioning. While several studies have explored the effects of landscape and climate factors on the success or failure of sagebrush seeding, the influence of soil properties on gradie...
Article
Full-text available
Improving predictions of restoration outcomes is increasingly important to resource managers for accountability and adaptive management, yet there is limited guidance for selecting a predictive model from the multitude available. The goal of this paper was to identify an optimal predictive framework for restoration ecology using eleven modeling fra...
Article
Full-text available
Long-term vegetation dynamics across public rangelands in the western United States are not well understood because of the lack of large-scale, readily available historic datasets. The Bureau of Land Management's Soil-Vegetation Inventory Method (SVIM) program was implemented between 1977 and 1983 across 14 western states, but the data have not bee...
Article
Full-text available
Context Reestablishing foundational plant species through aerial seeding is an essential yet challenging step for restoring the vast semiarid landscapes impacted by plant invasions and wildfire-regime shifts. A key component of the challenge stems from landscape variability and its effects on plant recovery. Objectives We assessed landscape correl...
Article
Full-text available
Restoration and rehabilitation of native vegetation in dryland ecosystems, which encompass over 40% of terrestrial ecosystems, is a common challenge that continues to grow as wildfire and biological invasions transform dryland plant communities. The difficulty in part stems from low and variable precipitation, combined with limited understanding ab...
Article
Full-text available
Statistically defensible information on vegetation conditions is needed to guide rangeland management decisions following disturbances such as wildfire, often for heterogeneous pastures. Here we evaluate sampling effort needed to achieve a robust statistical threshold using > 2 000 plots sampled on the 2015 Soda Fire that burned across 75 pastures...
Technical Report
Full-text available
The greater sage-grouse (Centrocercus urophasianus; hereafter GRSG) has been a focus of scientific investigation and management action for the past two decades. The 2015 U.S. Fish and Wildlife Service listing determination of “not warranted” was in part due to a large-scale collaborative effort to develop strategies to conserve GRSG populations and...
Article
Terrestrial laser scanning (TLS) has been shown to enable an efficient, precise, and non-destructive inventory of vegetation structure at ranges up to hundreds of meters. We developed a method that leverages TLS collections with machine learning techniques to model and map canopy cover and biomass of several classes of short-stature vegetation acro...
Article
Full-text available
Terrestrial laser scanning (TLS) provides fast collection of high-definition structural information, making it a valuable field instrument to many monitoring applications. A weakness of TLS collections, especially in vegetation, is the occurrence of unsampled regions in point clouds where the sensor’s line-of-sight is blocked by intervening materia...
Article
Full-text available
Larger, more frequent wildfires in arid and semi-arid ecosystems have been associated with invasion by non-native annual grasses, yet a complete understanding of fine fuel development and subsequent wildfire trends is lacking. We investigated the complex relationships among weather, fine fuels, and fire in the Great Basin, USA. We first modeled the...
Article
Full-text available
Our study objectives were to model the aboveground biomass in a xeric shrub-steppe landscape with airborne light detection and ranging (Lidar) and explore the uncertainty associated with the models we created. We incorporated vegetation vertical structure information obtained from Lidar with ground-measured biomass data, allowing us to scale shrub...
Article
Full-text available
Invasions by non-native plants can alter ecosystems such that new ecological states are reached, but less is known about how these transitions influence animal populations. Sagebrush (Artemisia tridentata) ecosystems are experiencing state changes because of fire and invasion by exotic annual grasses. Our goal was to study the effects of these stat...
Article
Full-text available
Sagebrush (Artemisia tridentata) ecosystems are declining due to biological invasions and changes in fire regimes. Understanding how ecosystem changes influence functionally important animals such as ecosystem engineers is essential to conserve ecological functions. American badgers (Taxidea tax-us) are an apex predator and ecosystem engineer in th...
Article
The Landsat 8 mission provides new opportunities for quantifying the distribution of above-ground carbon at moderate spatial resolution across the globe, and in particular drylands. Furthermore, coupled with structural information from space-based and airborne laser altimetry, Landsat 8 provides powerful capabilities for large-area, long-term studi...
Article
Full-text available
Harvester ants are influential in many ecosystems because they distribute and consume seeds, remove vegetation, and redistribute soil particles and nutrients. Understanding the interaction between harvester ants and plant communities is important for management and restoration efforts, particularly in systems altered by fire and invasive species su...
Conference Paper
Full-text available
Key Findings We successfully modeled the vegetation cover at a large scale using multispectral imagery (Landsat 8). The frequent occurrence of soil adjusted metrics in the model demonstrates the influence of bare soil reflectance in the spectral models in this rangeland ecosystem. We found the best model to describe vegetation cover fractions incl...
Article
Full-text available
Abstract. We compared As and Sb bioaccumulation and biomagnification when these metalloids co-occurred at varying environmental concentrations in a stream and wetlands near a contaminated mine site in Idaho (USA). We measured As and Sb concentrations in water and substrate samples, and in tissues of organisms representing several trophic levels. Bi...
Conference Paper
Full-text available
Remote sensing based quantification of semi-arid rangeland vegetation provides the large scale observations necessary for monitoring native plants distribution, estimating fuel loads and measuring carbon storage. Improved signal to noise ratio and radiometric resolution of recent satellite imagery and fine scale 3-dimensional information from lidar...
Article
The loss of big sagebrush (Artemisia tridentata Nutt.) on sites disturbed by fire has motivated restoration seeding and planting efforts. However, the resulting sagebrush establishment is often lower than desired, especially in dry areas. Sagebrush establishment may be increased by addressing factors such as seed source and condition or management...
Article
Full-text available
Amphibian species persisting in isolated streams and wetlands in desert environments can be susceptible to low connectivity, genetic isolation, and climate changes. We evaluated the past (1900–1930), recent (1981–2010), and future (2071–2100) climate suitability of the arid Great Basin (USA) for the Columbia spotted frog (Rana luteiventris) and ass...
Article
Full-text available
A common challenge in the conservation of broadly distributed, yet imperiled species is understanding which factors facilitate persistence at distributional edges, locations where populations are often vulnerable to extirpation due to changes in climate, land use, or distributions of other species. For Columbia spotted frogs (Rana luteiventris) in...
Conference Paper
Full-text available
Quantifying aboveground total biomass of sagebrush (Artemisia tridentata), as well as native and non-native grasses, is important for modeling climate and hydrological dynamics, estimating pre-fire and post-fire fuel loads, measuring carbon storage, assessing habitat quality and managing changes in sagebrush-steppe environments. Remote sensing data...
Conference Paper
Full-text available
Understanding and quantifying biomass of sagebrush (Artemisia tridentata), as well as native and non-native grasses, is important for managing changes to the sagebrush-steppe, modeling vegetation dynamics, estimating pre-fire and post-fire fuel loads, measuring carbon storage and assessing habitat quality. Remote sensing techniques can be exploited...
Conference Paper
Background/Question/Methods Columbia spotted frogs in southeastern Oregon, southern Idaho, and Nevada constitute a genetically distinct population segment (DPS) of Rana luteiventris. This Great Basin DPS has been a Candidate for Listing under the Endangered Species Act since 1993 because remaining populations are small, isolated, and reside in ha...
Article
Invasive annual grasses alter fire regimes in shrubland ecosystems of the western USA, threatening ecosystem function and fragmenting habitats necessary for shrub-obligate species such as greater sage-grouse. Post-fire stabilization and rehabilitation treatments have been administered to stabilize soils, reduce invasive species spread and restore o...
Article
Environmental DNA (eDNA) methods for detecting and estimating abundance of aquatic species are emerging rapidly, but little is known about how processes such as secretion rate, environmental degradation, and time since colonization or extirpation from a given site affect eDNA measurements. Using stream-dwelling salamanders and quantitative PCR (qPC...
Article
Full-text available
Environmental DNA (eDNA) methods for detecting aquatic species are advancing rapidly, but with little evaluation of field protocols or precision of resulting estimates. We compared sampling results from traditional field methods with eDNA methods for two amphibians in 13 streams in central Idaho, USA. We also evaluated three water collection protoc...
Conference Paper
Background/Question/Methods Federal land management agencies, particularly the Bureau of Land Management (BLM), have invested heavily in post-fire seedings in Great Basin sage steppe ecosystems of the western U.S. These seedings are typically implemented to reduce both soil erosion and post-fire dominance of non-native annual grasses while also m...
Article
Full-text available
We examined the effects of three early season (spring) prescribed fires on burn severity patterns of summer wildfires that occurred 1–3 years post-treatment in a mixed conifer forest in central Idaho. Wildfire and prescribed fire burn severities were estimated as the difference in normalized burn ratio (dNBR) using Landsat imagery. We used GIS deri...
Article
Prescribed fires and wildland fire-use are increasingly important management tools used to reduce fuel loads and restore the ecological integrity of western forests. Although a basic understanding of the effects of fire on aquatic ecosystems exists, the cumulative and possibly synergistic effects of wildfire following prescribed fire are unknown. W...
Data
PCR protocols and results for amplifying DNA of Rocky Mountain tailed frogs (Ascaphus montanus) and Idaho giant salamanders (Dicamptodon aterrimus) from stream water. (DOCX)
Article
Full-text available
1. The complex effects of disturbances on ecological communities can be further complicated by subsequent perturbations within an ecosystem. We investigated how wildfire interacts with annual variations in peak streamflow to affect the stability of stream macroinvertebrate communities in a central Idaho wilderness, USA. We conducted a 4-year retros...

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Projects (2)
Project
The SageSuccess Project is a joint effort between USGS, BLM, and FWS to understand how to establish big sagebrush and ultimately restore functioning sagebrush ecosystems. Improving the success of land management treatments to restore sagebrush-steppe is important for reducing the long-term impacts of rangeland fire on sage-grouse and over 350 other wildlife species that use these habitats. The project will evaluate treatments completed between 1990 and 2013 and determine the treatment methods and environmental factors that have contributed to past restoration success. This research will help inform future land management activities and contribute to the development of new practices or improvement of existing methods to restore sagebrush ecosystems. Ultimately, this research could improve the efficacy and efficiency of investments made by federal, state, NGO, and private entities to restore the stability and productivity of rangelands.