Todd Esque
Dr. Todd Esque's research interests are in disturbance ecology with emphasis in areas of community ecology, herpetology, invasive species and fire, habitat restoration, and conservation biology.
Dr. Esque's work focuses on understanding how organisms, habitats, and ecosystem processes respond to environmental change, how organisms interact to effect change, and how human-induced changes compare to the natural range of variation in arid systems. Recent work focuses on the synthesis of these experiments into regional analyses of habitat suitability and connectivity in response to global change and other anthropogenic disturbances for use by natural resource managers.
Representative studies include: projects to determine how desert tortoises, Mojave ground squirrels, golden eagles, long-lived plants, and biodiversity will respond to climate change and energy development in a rapidly changing landscape; vegetation change from fires across a 30-year chronosequence in Sonoran desert tortoise habitat; identifying habitat and health relationships for the desert tortoise, and developing a vegetation restoration program for the Mojave Desert.
Dr. Esque's projects are collaborative and interdisciplinary in nature and he is active in academic research as well as applied problems for public entities in the Department of Interior (Bureau of Land Management, National Park Service, U.S. Fish and Wildlife Service), Department of Defense, State and local governments, and private entities.
RESEARCH INTERESTS
- Arid Systems
- Conservation Biology
- Disturbance and Restoration Ecology
- Demographic and Habitat Modeling
- Community Ecology
- Invasive Species and Wildfire
- Energy Development
EDUCATION
- 2004 Ph.D. Ecology Evolution, and Conservation Biology, University of Nevada, Reno
- 1994 M.S. Zoology, Colorado State University
- 1982 B.A. Biology, Prescott College, Arizona
PROFESSIONAL AND HONORARY SOCIETIES AND SCIENCE ADVISORY COMMITTEES
- Desert Renewable Energy Conservation Plan – Science Advisory Committee 2012
- BLM – Rapid Ecoregional Assessments – lead USGS science reviewer for the Mojave and Sonoran Ecoregions 2013
PROFESSIONAL EXPERIENCE
- Research Ecologist, USGS, Western Ecological Research Center, 1997-Present
- Station Leader, USGS, St. George Field Station, 1994-1997
- Research Ecologist, USGS, Mid-continent Ecological Science Center, 1996- 1997
- Research Ecologist, National Biological Service (Survey), Mid-continent Ecological Science Center, 1993 - 1996
- Ecologist, Bureau of Land Management, Dixie Resource Area, Utah, 1993 - 1993
- Research Technician, Fish and Wildlife Service, Region 8, Research, Ft. Collins, CO 1986-1993
Science and Products
Quantifying development to inform management of Mojave and Sonoran desert tortoise habitat in the American southwest
Using remotely sensed data to map Joshua Tree distributions at Naval Air Weapons Station China Lake, California, 2018
Genes in space: What Mojave desert tortoise genetics can tell us about landscape connectivity
A range-wide model of contemporary, omnidirectional connectivity for the threatened Mojave desert tortoise
Spatially consistent high-resolution land surface temperature mosaics for thermophysical mapping of the Mojave Desert
Local niche differences predict genotype associations in sister taxa of desert tortoise
Tools to understand seasonality in health: quantification of microbe loads and analyses of compositional ecoimmunological data reveal complex patterns in Mojave Desert Tortoise (Gopherus agassizii) populations
Arizona hedgehog cactus (Echinocereus triglochidiatus var. arizonicus)—A systematic data assessment in support of recovery
Complex immune responses and molecular reactions to pathogens and disease in a desert reptile (Gopherus agassizii)
Spatial decision‐support tools to guide restoration and seed‐sourcing in the Desert Southwest
Spatial sampling bias in the Neotoma paleoecological archives affects species paleo-distribution models
Associating sex-biased and seasonal behaviour with contact patterns and transmission risk in Gopherus agassizii
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Quantifying development to inform management of Mojave and Sonoran desert tortoise habitat in the American southwest
Two tortoise species native to the American southwest have experienced significant habitat loss from development and are vulnerable to ongoing threats associated with continued development. Mojave desert tortoises Gopherus agassizii are listed as threatened under the US Endangered Species Act, and Sonoran desert tortoises G. morafkai are protected in Arizona (USA) and Mexico. Substantial habitat fAuthorsSarah K. Carter, Kenneth E. Nussear, Todd C. Esque, Ian IF Leinwand, Elroy Masters, Rich Inman, Natasha B. Carr, Linda J. AllisonUsing remotely sensed data to map Joshua Tree distributions at Naval Air Weapons Station China Lake, California, 2018
Species distribution models (SDMs) that are derived through inference have been used to provide important insights toward species distributions. Their inferences can be robust in relation to known presences, but SDMs have error rates that cannot be quantified with certainty. For large plant species with unique signatures and in sparsely vegetated habitats, object-oriented satellite image interpretAuthorsTodd C. Esque, Patrick E. Baird, Felicia C. Chen, David C. Housman, Tom J. HoltonGenes in space: What Mojave desert tortoise genetics can tell us about landscape connectivity
Habitat loss and fragmentation in the Mojave Desert have been increasing, which can create barriers to movement and gene flow leading to decreased populations of native species. Disturbance and degradation of Mojave desert tortoise habitat includes linear features (e.g. highways, railways, and a network of dirt roads), urbanized areas, and their associated infrastructure, mining activities, energyAuthorsKirsten E. Dutcher, Amy G. Vandergast, Todd C. Esque, Anna Mitelberg, Marjorie D Matocq, Jill S. Heaton, Ken E NussearA range-wide model of contemporary, omnidirectional connectivity for the threatened Mojave desert tortoise
As habitat destruction leads to species extinctions globally, conservation planning that accounts for population-level connectivity and gene flow is an urgent priority. Models that only approximate habitat potential are incomplete because areas of high habitat potential may be isolated, whereas intermixed areas of lower habitat potential may still be critical for maintaining connectivity between aAuthorsMiranda E Gray, Brett G. Dickson, Kenneth E. Nussear, Todd C. Esque, Tony ChangSpatially consistent high-resolution land surface temperature mosaics for thermophysical mapping of the Mojave Desert
Daytime and nighttime thermal infrared observations acquired by the ASTER and MODIS instruments onboard the NASA Terra spacecraft have produced a dataset that can be used to map thermophysical properties across large regions, which have implications on surface processes, thermal environments and habitat suitability for desert species. ASTER scenes acquired between 2004 and 2012 are combined usingAuthorsScott A Nowicki, Rich Inman, Todd C. Esque, Kenneth E. Nussear, Christopher S. EdwardsLocal niche differences predict genotype associations in sister taxa of desert tortoise
Aims To investigate spatial congruence between ecological niches and genotype in two allopatric species of desert tortoise that are species of conservation concern. Location Mojave and Sonoran Desert ecoregions; California, Nevada, Arizona, Utah, USA. Methods We compare ecological niches of Gopherus agassizii and Gopherus morafkai using species distribution modelling (SDM) and then calibrate a pooAuthorsRich Inman, A. Stewart Fotheringham, Janet Franklin, Todd C. Esque, Taylor Edwards, Kenneth E. NussearTools to understand seasonality in health: quantification of microbe loads and analyses of compositional ecoimmunological data reveal complex patterns in Mojave Desert Tortoise (Gopherus agassizii) populations
Using data from six wild Mojave Desert Tortoise (Gopherus agassizii (Cooper, 1861)) populations, we quantified seasonal differences in immune system measurements and microbial load in the respiratory tract, pertinent to this species’ susceptibility to upper respiratory tract disease. We quantified bacteria-killing activity of blood plasma and differential leukocyte counts to detect trends in tempoAuthorsF. C. Sandmeier, K. L. Leonard, C. R. Tracy, K. Kristina Drake, Todd C. Esque, K. E. Nussear, J GermanoArizona hedgehog cactus (Echinocereus triglochidiatus var. arizonicus)—A systematic data assessment in support of recovery
The Arizona hedgehog cactus (Echinocereus triglochidiatus var. arizonicus) is endemic to central Arizona in Gila and Pinal Counties, and has been federally listed as endangered by the U.S. Fish and Wildlife Service (FWS) since 1979. Mining, mineral exploration, and highway development have resulted in habitat degradation and loss of individual plants. Therefore, decreases in the population of theAuthorsKathryn A. Thomas, Daniel F. Shryock, Todd C. EsqueComplex immune responses and molecular reactions to pathogens and disease in a desert reptile (Gopherus agassizii)
Immune function plays an important role in an animal's defense against infectious disease. In reptiles, immune responses may be complex and counterintuitive, and diagnostic tools used to identify infection, such as induced antibody responses are limited. Recent studies using gene transcription profiling in tortoises have proven useful in identifying immune responses to various intrinsic and extrinAuthorsK. Kristina Drake, Christina M. Aiello, Lizabeth Bowen, Rebecca L. Lewison, Todd C. Esque, Kenneth E. Nussear, Shannon C. Waters, Peter J. HudsonSpatial decision‐support tools to guide restoration and seed‐sourcing in the Desert Southwest
Altered disturbance regimes and shifting climates have increased the need for large‐scale restoration treatments across the western United States. Seed‐sourcing remains a considerable challenge for revegetation efforts, particularly on public lands where policy favors the use of native, locally sourced plant material to avoid maladaptation. An important area of emphasis for public agencies has beeAuthorsDaniel F. Shryock, Lesley A. DeFalco, Todd C. EsqueSpatial sampling bias in the Neotoma paleoecological archives affects species paleo-distribution models
The ability to infer paleo-distributions with limited knowledge of absence makes species distribution modeling (SDM) a useful tool for exploring paleobiogeographic questions. Spatial sampling bias is a known issue when modeling extant species. Here we quantify the spatial sampling bias in a North American packrat midden archive and explore its impact on estimating paleo-distributions. We test whetAuthorsRich Inman, Janet Franklin, Todd C. Esque, Kenneth E. NussearAssociating sex-biased and seasonal behaviour with contact patterns and transmission risk in Gopherus agassizii
Interactions between wildlife hosts act as transmission routes for directly transmitted pathogens and vary in ways that affect transmission efficiency. Identifying drivers of contact variation can allow both contact inference and estimation of transmission dynamics despite limited data. In desert tortoises, mating strategy, burrow use and seasonal change influence numerous behaviours and likely shAuthorsChristina M. Aiello, Todd C. Esque, K. E. Nussear, P. G. Emblidge, Peter J. Hudson - Web Tools
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