Research · Ecological Management

Fish and Wildlife Modeling

History of Ecological Modeling in ESD

Overview of ESD's history in modelingTheoretical ecology and research involving ecological models has a long history in ORNL. Beginning with ecosystem and trophic models, researchers in ESD branched into landscape ecology, risk assessment, individual-based modeling, and population viability analysis (PVA). Most recently, we are using PVA models to address both applied and theoretical questions in conservation and landscape ecology. Research in ecosystem modeling, landscape ecology, and risk assessment continue to be important areas of interest. A very simplified overview of our history in modeling, including both applied and theoretical research, is presented in this figure. (Read more...)

Current Research

ORNL has developed and applied population models for quite a few species, including species of conservation concern. In many cases, conservation concern is the driver for studying population responses, and in others, research questions focus on the impacts of a potential stressor associated with human activities (e.g., regulated flows, dams, oil production). We have studied species of conservation concern from a broad range of taxa, including butterflies, fish, birds, and mammals. A landmark event in these efforts was a workshop on "Ecological Modeling for Resource Management" in 2002, which led to a book edited by V. Dale. The program that produced this workshop had the goal of developing spatially-explicit ecological models for resource management that identified, in a spatial context, natural resources at risk, temporal and spatial trends, and key features of resources that should be monitored. The main product of this research, which targeted four species (butterflies, two territorial migrants, and red-cockaded woodpecker) were metapopulation models linking each species to relevant spatially explicit management information and risk maps. With this broad background in diverse types of species, one goal of our future research is to better understand how life histories of these species, and particularly spatial life histories, influence the likelihood of persistence and vulnerability to different risks. Below, we describe the aforementioned research efforts in more detail.


Population Viability Analysis of the Blue Karner butterfly--The Blue Karner butterfly (Lycaeides melissa samuelis) is a federally endangered species that depends on wild blue lupine. A metapopulation model was developed with a patch structure to represent suitable areas with lupine. (Read more...)


Population Viability Analysis of Henslow's sparrow and the cerulean warbler-- The territorial migrant model [right click to download, left click to view] addresses population demographics of bird species that are migratory and establish breeding territories. The model has been parameterized for and applied to on the Department of Energy's Oak Ridge Reservation, Tennessee, Henslow's sparrows (Ammodramus henslowii) at both Fort Knox, Kentucky and Fort Riley, Kansas, and for golden-cheeked warbler (Dendroica chrysoparia) and black-capped vireo (Vireo atricapillus) at Fort Hood, Texas. (Read more...) This species-centric, applied model has been generalized in collaboration with Dr. Kim With of Kansas State University to investigate theoretical questions of how spatial pattern and structure influence avian demography. (Read more...)

Population Viability Analysis of the Red-cockaded woodpecker--Modeling research for this species, Picoides borealis, asked the following questions: (1) Can the red-cockaded woodpecker be managed as a regional metapopulation? (2) Is the current distribution of red-cockaded woodpecker habitat consistent with long-term regional persistence? and (3) If not, what changes in habitat distribution or other management interventions would promote regional persistence? (Read more...)

Population Viability Analysis of Sage grouse--The Bureau of Land Management (BLM) is interested in studying the effects of oil exploration and development on species of conservation concern on their lands. We will use a terrestrial PVA model to examine this question for the sage grouse (Centrocercus urophasianus) in northeastern Utah. One question will be to seek a spatially optimal arrangement of oil wells that protects this species from future harm.


Population Viability Analysis of Sturgeons--Sturgeons are a group of fishes that are at great risk of decline, in part because of changes in the large-river habitat and fragmentation by dams. ORNL has been involved in using individual-based models for Population Viability Analysis (PVA) of two sturgeon species.

White sturgeon: We conducted a PVA of white sturgeon (Acipenser transmontanus) populations between dams in the Snake River, USA. A PVA model for this species has been used to rank threats and evaluate management alternatives proposed as part of relicensing for Middle Snake River dams. (Read more...)

Pallid sturgeon: We developed a PVA model for the endangered Pallid sturgeon (Scaphirhynchus albus) in the Missouri and Yellowstone rivers. One issue for the Pallid sturgeon is hybridization with the closely related and abundant shovelnose sturgeon, which we were able to address through the genetic component of the IBM.

Flow Effects on River Fishes--ORNL researchers have used IBMs to study the relationship between the river environment, particularly streamflow, and fish populations. As part of the EPRI COMPMECH program, Mike Sale proposed the use of these IBM’s as a tool for setting instream-flow regulations (i.e., minimum flows). Linkages with flow involve bioenergetic costs of “living in the fast lane”, flow-related disruption of reproduction (e.g., redd scouring or nest desertion), influences on food availability in drift, and mortality (e.g., due to extreme temperatures, which are mediated by flow releases in tailwaters). Such models were developed for smallmouth bass, brown trout, rainbow trout, and Chinook salmon. Of these species, all but brown trout are native, and fall-run Chinook salmon, although not listed, is a species of conservation concern.

We used the Chinook salmon model (ORCM) to design optimal flow regimes either to maximize the number of salmon recruits or to maximize the diversity of run times among recruits. We are now comparing the ORCM model against data collected over the past ten years. (Read more...)


Population Viability Analysis of the American badger--Although the American badger (Taxidea taxus) is not a species of high conservation concern, this species provided ORNL with an opportunity to develop a terrestrial PVA model to examine landscape and spatial impacts associated with habitat loss and fragmentation, which is the predominant threat to most species of concern. The model was applied at the Tallgrass Prairie Preserve in Oklahoma, owned by The Nature Conservancy. The specific goal of this project was to evaluate the effects of habitat loss and fragmentation due to oil exploration and production. Results suggested that habitat loss and fragmentation force mustelids like the badger to travel farther to find mates, during which time they are exposed to higher risks. Allee effects also contribute to declines in highly fragmented landscapes. (Read more...)

For more information, contact:
Mark Bevelhimer (, 865-576-0266)
Virginia Dale (, 865-576-8043 )
Rebecca Efroymson (, 865-574-7397)
Yetta Jager (, 865-574-8143)
Tony King (, 865-576-3436)

Revised: 10/06/05

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