Geology topics

Steve E. Hanser

Publications and source records attributed to Steve E. Hanser.

24 records · Page 2Linked to original sources

USGS2016

Science framework for the conservation and restoration strategy of DOI secretarial order 3336: Utilizing resilience and resistance concepts to assess threats to sagebrush ecosystems and greater sage-grouse, prioritize conservation and restoration actions, and inform management strategies

The Science Framework for the Conservation and Restoration Strategy of the Department of the Interior, Secretarial Order 3336 (SO 3336), Rangeland Fire Prevention, Management and Restoration, provides a strategic, multiscale approach for prioritizing areas for management and determining effective management strategies across the sagebrush biome. The emphasis of this version is on sagebrush ecosystems and greater sage-grouse. The Science Framework uses a six step process in which sagebrush ecosystem resilience to disturbance and resistance to nonnative, invasive annual grasses is linked to species habitat information based on the distribution and abundance of focal species. The predominant ecosystem and anthropogenic threats are assessed, and a habitat matrix is developed that helps decision makers evaluate risks and determine appropriate management strategies at regional and local scales. Areas are prioritized for management action using a geospatial approach that overlays resilience and resistance, species habitat information, and predominant threats. Decision tools are discussed for determining the suitability of priority areas for management and the most appropriate management actions at regional to local scales. The Science Framework and geospatial crosscut are intended to complement the mitigation strategies associated with the Greater Sage-Grouse Land Use Plan amendments for the Department of the Interior Bureaus, such as the Bureau of Land Management, and the U.S. Forest Service.

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USGS2011

Chapter 5: Greater sage-grouse: General use and roost site occurrence with pellet counts as a measure of relative abundance

Greater sage-grouse ( Centrocercus urophasianus ) have been declining both spatially and numerically throughout their range because of anthropogenic disturbance and loss and fragmentation of sagebrush ( Artemisia spp.) habitats. Understanding how sage-grouse respond to these habitat alterations and disturbances, particularly the types of disturbances and extent at which they respond, is critical to designing management actions and prioritizing areas of conservation. To address these needs, we developed statistical models of the relationships between occurrence and abundance of greater sage-grouse and multi-scaled measures of vegetation, abiotic, and disturbance in the Wyoming Basins Ecoregional Assessment (WBEA) area. Sage-grouse occurrence was strongly related to the amount of sagebrush within 1 km for both roost site and general use locations. Roost sites were identified by presence of sage-grouse fecal pellet groups whereas general use locations had single pellets. Proximity to anthropogenic disturbance including energy development, power lines, and major roads was negatively associated with sage-grouse occurrence. Models of sage-grouse occurrence correctly predicted active lek locations with >75% accuracy. Our spatially explicit models identified areas of high occurrence probability in the WBEA area that can be used to delineate areas for conservation and refine existing conservation plans. These models can also facilitate identification of pathways and corridors important for maintenance of sage-grouse population connectivity.

Wyoming↗

USGS2011

Chapter 6: Detectability adjusted count models of songbird abundance

Sagebrush ( Artemisia spp.) steppe ecosystems have experienced recent changes resulting not only in the loss of habitat but also fragmentation and degradation of remaining habitats. As a result, sagebrush-obligate and sagebrush associated songbird populations have experienced population declines over the past several decades. We examined landscape-scale responses in occupancy and abundance for six focal songbird species at 318 survey sites across the Wyoming Basins Ecoregional Assessment (WBEA) area. Occupancy and abundance models were fit for each species using datasets developed at multiple moving window extents to assess landscape-scale relationships between abiotic, habitat, and anthropogenic factors. Anthropogenic factors had less influence on species occupancy or abundance than abiotic and habitat factors. Sagebrush measures were strong predictors of occurrence for sagebrush-obligate species, such as Brewer’s sparrows ( Spizella breweri ), sage sparrows ( Amphispiza belli ) and sage thrashers ( Oreoscoptes montanus ), as well as green-tailed towhees ( Pipilo chlorurus ), a species associated with mountain shrub communities. Occurrence for lark sparrows ( Chondestes grammacus ) and vesper sparrows ( Pooecetes gramineus ), considered shrub steppe-associated species, was also related to big sagebrush communities, but at large spatial extents. Although relationships between anthropogenic variables and occurrence were weak for most species, the consistent relationship with sagebrush habitat variables suggests direct habitat loss and not edge or additional fragmentation effects are causing declines in the avifauna examined in the WBEA area. Thus, natural and anthropogenic disturbances that result in loss of critical habitats are the biggest threats to these species. We applied our models spatially across the WBEA area to identify and prioritize key areas for conservation.

Wyoming↗

USGS2011

Chapter 7: Occurrence and abundance of ants, reptiles, and mammals

Sagebrush ( Artemisia spp.)- associated wildlife are threatened by habitat loss and fragmentation and by impacts associated with anthropogenic disturbances, including energy development. Understanding how species of concern as well as other wildlife including insects, reptiles, and mammals respond to type and spatial scale of disturbance is critical to managing future land uses and identifying sites that are important for conservation. We developed statistical models to describe species occurrence or abundance, based on area searches in 7.29-ha survey blocks, across the Wyoming Basins Ecoregional Assessment (WBEA) area for six shrub steppe-associated species: harvester ant ( Pogonomyrmex spp.), thatch ant ( Formica spp.), short-horned lizard ( Phrynosoma hernandesi ), white-tailed jackrabbit ( Lepus townsendii ), cottontail ( Sylvilagus spp.) and least chipmunk ( Tamius minimus ). We modeled patterns in occupancy or abundance relative to multi-scale measures of vegetation type and pattern, abiotic site characteristics, and anthropogenic disturbance factors. Sagebrush habitat was a strong predictor of occurrence for shorthorned lizards and white-tailed jackrabbits, but weak for the other four species. Vegetation and abiotic characteristics were strong determinants of species occurrence, although the scale of response was not consistent among species. All species, with the exception of the short-horned lizard, responded to anthropogenic disturbance, although responses again varied as a function of scale and direction (negative and positive influences). Our results improve our understanding of how environmental and anthropogenic factors affect species distributions across the WBEA area and facilitate a multi-species approach to management of this sagebrush ecosystem.

Wyoming↗

USGS2011

Chapter 8: Occurrence of large and medium-sized mammals: Occurrence but not count models predict pronghorn distribution

Management of medium to large-sized terrestrial mammals (Antilocapridae, Canidae, Cervidae, Leporidae, Mustelidae, Ochotonidae) in the western United States is multifaceted and complex. Species in this group generally are charismatic and provide economic opportunities, although others are considered a nuisance at one extreme or are listed as species of conservation concern at the other. Understanding the relative influence of land cover, habitat fragmentation, and human land use on their distribution during the breeding season is imperative to inform management decisions on land use and conservation planning for these species. We surveyed medium to large-sized sagebrush ( Artemisia spp.)-associated mammal species in 2005 and 2006 on 141 random transects (mean length = 1.1 km) in the Wyoming Basins, an area undergoing rapid land cover transformation due to human actions including energy development. Overall, we observed 10 species but only obtained enough observations of pronghorn ( Antilocapra americana ) to develop spatially explicit distribution models. For pronghorn, occurrence related positively to proportion of sagebrush land cover within 0.27 km, mixed shrubland land cover within 3 km, riparian land cover within 5 km, Normalized Difference Vegetation Index (NDVI) within 0.27 km, road density within 5 km, and decay distance to power line corridors at 1 km, but negatively to salt-desert shrubland cover within 18 km and an interaction between sagebrush and NDVI within 0.27 km. We found excellent predictive capability of this model when evaluated with independent test data. The model provides a basis for assessing the effects of proposed development on pronghorn and can aid planning efforts to avoid or mitigate adverse effects on pronghorn.

Wyoming↗

USGS2011

Introduction: An ecoregional assessment of the Wyoming Basins

The Wyoming Basins Ecoregional Assessment (WBEA) area in the western United States contains a number of important land cover types, including nearly one-fourth of the sagebrush ( Artemisia spp.) in North America. Although relatively unappreciated until recent decades, the broad open landscapes dominated by sagebrush communities have received increasing attention for their ecological value and the resources that they contain (Knick and Connelly 2011). As many as 350 wildlife species depend on sagebrush ecosystems for all or part of their life requirements (Wisdom et al. 2005a). Within the WBEA, intact sagebrush landscapes provide an important stronghold for populations of greater sage-grouse ( Centrocercus urophasianus ), recently listed as a candidate species under the Endangered Species Act (U.S. Department of the Interior 2010). Numerous other plant and vertebrate species of state or national concern also occur within the WBEA study area (Ch. 2). Conserving sagebrush ecosystems is a major conservation challenge that will require an understanding not only of current trajectories and scales of habitat change due to natural and anthropogenic disturbances (Leu and Hanser 2011), but also the potential exacerbation of these trends from climate change (Wiens and Bachelet 2010, Miller et al. 2011).

Wyoming↗