Natural Resource Ecology Laboratory

Selected Current Research Projects

1) Wyoming Basins Ecoregional Assessment

This is a collaborative research project led by the USGS, the Forest Service, CSU, and funded by the Bureau of Land Management. We are developing an ecoregional planning tool for BLM lands across the greater Wyoming Basins area. This project involves extensive GIS analyses, developing landscape scale predictive models for a variety of vertebrate species of concern. We are currently completing the preliminary species models, and have completed the initial years of field data collection for empirical model development and validation. These ecoregional planning tools will be used by the BLM as a management tools across regional and state field offices.

Collaborative research project between the following Individuals/Organizations:

Funding Support for the Wyoming Basins Ecoregional Assessment:

Preliminary report:

Rowland, M.M., M. Leu, S. Hanser, S.P. Finn, C.L. Aldridge, S.T. Knick, L.H. Suring, J. M. Boyd, M.J. Wisdom, and C.W. Meinke. 2006. Assessment of threats to sagebrush habitats and associated species of concern in the Wyoming Basins. Version 2.0, March 2006, unpublished report on file at USGS Biological Resources Discipline, Snake River Field Station, 970 Lusk St., Boise , ID 83706.

2) Range-wide patterns of sage-grouse extirpation: lessons from the past, predictions for the future.

While local studies to address population declines are numerous, large scale range-wide analyses to address both patterns and processes of range contractions and population declines have never been attempted. We developed a series of range-wide habitat-based occupancy models for sage-grouse, contrasting 1) currently occupied (extant) and previously occupied (extinct) habitat. We use these models to identify habitat variables (i.e. sagebrush habitat), peripherality, drought conditions, and human-related parameters (i.e. human population density, agriculture, road densities) that best predict known local extinctions. Our models predict that Greater Sage-Grouse range extirpations are more likely in areas that had a greater population density, in areas that have had a greater proportion of habitat converted to cultivated crops, and where drier climates prevail and more sever droughts have occurred since 1950. Conversely, populations are more likely to persist in habitats that are less peripheral or further from the historic species range, and in habitats that contain a greater proportion of sagebrush habitat with the mean annual home range of sage-grouse. We use these models to identify which populations are considered secure and identify those most likely at risk of future extirpation.

Example Publication:

Aldridge, C.L., S.E. Nielsen, H.L. Beyer, M.S. Boyce, J.W. Connelly, S.T. Knick, and M.A. Schroeder. 2008. Range-wide patterns of greater sage-grouse persistence. Diversity and Distributions 14: 983-994. Reprinted with cooperation from Blackwell Publishing

Collaborative research project between the following Individuals/Organizations:

Funding Support for this Project:

 

3) Mapping sagebrush habitats across Wyoming

This is a research project that we are just getting underway. Despite current research identifying resource requirements for many sagebrush obligate species at local scales, a lack of methodologies to accurately assess and monitor habitats at large scales has prevented landscape scale management from occurring. The goal of this project is to develop statistically rigorous mapping products to assess habitat within the sagebrush ecosystem. We will use color aerial photographs to accurately assess and map roads, trails and oil and gas infrastructure. While methodologies (i.e. airphoto interpretation) are available to accurately identify anthropogenic features within sagebrush habitats, the techniques do not currently exist to assess and map sagebrush habitats throughout western North America. We will use high resolution remotely sensed imagery (i.e. Quickbird ~0.6 m resolution) to develop methodologies to identify and map species, cover, and height classes of sagebrush (Artemisia spp). We will attempt to 'scale up' these sagebrush models, applying them to larger landscapes. These products will be the backbone for future management and planning efforts on BLM lands, and directly assist with species and ecosystem assessments, like the BLM funded Wyoming Basins Ecoregional Assessment (above), and have huge implications for landscape scale habitat management for sage-grouse (Centrocercus spp.) and other sagebrush obligate species. This research will provide the BLM managers with the foundation for quantifying and assessing sagebrush habitats and anthropogenic influences.

Example Publication:

Homer, C.G., C.L. Aldridge, D.K. Meyer, M.J. Coan, and Z.H. Bowen. 2009. Multiscale Sagebrush Rangeland Habitat Modeling in Southwest Wyoming. U.S. Geological Survey Open-File Report 2008-1027.

Collaborative research project between the following Individuals/Organizations:

Funding Support for this Project:

 

4) Quantifying the physical impacts of re-enacted Mormon handcart journeys across the historic Oregon-California trail: an aerial photography approach to assess impacts and develop use thresholds in Wyoming

Recently (beginning in 1998), Mormon handcart emigrant companies began re-enacting their ancestors’ historic westward trips along the historic Oregon California trail in Wyoming, resulting in short duration but intense use of certain sections of the trail. This trail is very much considered a historic relic, and concern exists over the extensive damage that may be caused to the trail through the intense use of wagons, handcarts, and motorized vehicles during these reenactments. Unfortunately, the historic state of the trail is not known, and the impacts of current intensive trail use have not been assessed. We are working with the BLM to understand the impacts of these re-enactments to the trail, and develop defensible threshold levels of use that will allow the Historic Trail to remain relatively intact. The BLM has identified a severely impacted 25-mile segment of the historic Oregon-California Trail that extends from the sixth Crossing of the Sweetwater River to Rock Creek. We will measure a broad spectrum of intensities of use by quantifying impacts along this heavily used section, and along sections of the trail that are exposed only to moderate and light use. We will use high resolution (i.e. 1:4,000 scale) aerial photographs to quantify use and impacts to the historic Oregon-California Trail, associated social trails. We will develop models that predicts impacts based on the intensity, duration, and type of use. These models will allow us to development ‘thresholds of use’ that will allow BLM managers to establish use levels. The ‘threshold of use’ measures will provide BLM managers with an objective and quantifiable means of establishing the numbers and types of users that can access the historic Oregon-California Trail with corresponding levels of impact.

Collaborative research project between the following Individuals/Organizations:

Funding Support for this Project:

 

5) Sage-grouse winter habitat assessment in southwestern Wyoming using remotely sensed data

Little is known about the landscape scale distribution and habitat requirements of greater sage-grouse in the winter. We are mapping sage-grouse winter habitat in a southwest portion of Wyoming for the BLM (Rock Springs Field Office) using remotely sensed data, habitat maps, and snow fall records. We have identified large patches of sagebrush (Artemisia spp.) habitat that remain exposed over the winter, providing suitable food and cover resources throughout the winter.

Collaborative research project between the following Individuals/Organizations:

Funding Support for this Project:

 

6) Stratton sagebrush ecology research study area

The Stratton sagebrush study site is a long-term BLM sagebrush ecology research site. We are assessing the impacts of grazing (domestic and native), as well as managed burns on the vegetation community, range condition, and associated wildlife use of different habitats. We have three different cattle grazing treatments, each with controls and burn treatments. Within each treatment we have exclosures and grazing cages, allowing us to measure grazing pressure and offtake. Across each treatment, we are assessing greater sage-grouse (Centrocercus urophasianus) abundance and habitat use (permanent pellet transects) songbird (point counts) and small mammal abundance (live trapping) and habitat associations. Similar wildlife and vegetation studies were conducted 30 years ago at this site, which will act as a useful reference comparison.

Example Publication:

Erickson, H.J., C.L. Aldridge, and N.T. Hobbs. 2008. Progress Report: Stratton Ecological Research Site-An Experimental Approach to Assess Effects of Various Grazing Treatments on Vegetation and Wildlife Communities Across Managed Burns and Habitat Controls. U.S. Geological Survey Open-File Report 2009-1016, 15p.

Collaborative research project between the following Individuals/Organizations:

Funding Support for this Project: