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.
- Arid Systems
- Conservation Biology
- Disturbance and Restoration Ecology
- Demographic and Habitat Modeling
- Community Ecology
- Invasive Species and Wildfire
- Energy Development
- 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
- 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
WERC Fire Science
Aridlands Disturbances and Restoration Ecology
Ecology and Conservation of Golden Eagles in the Mojave Desert
Desert Tortoise Ecology, Health, Habitat, and Conservation Biology
Southwestern Desert Ecology of At-risk Species and their Habitats
Boulder City Field Station
Ecological and Disease Data for Induced Immune Responses and Antibody Levels for Mycoplasma spp. in Captive and Wild Mojave Desert Tortoises (Gopherus agassizii)
Species Distribution Models for Native Species in the Mojave Desert
Ecotypic Variation in Ambrosia dumosa and Larrea tridentata from Three Sites Across the Mojave (2014 - 2018)
Mojave Desert Tortoise (Gopherus agassizii) Morphometrics and Egg Data from Seven Sites across the Mojave, (1997-2002)
Genetic and Habitat Data for Plantago ovata in the Mojave Desert
Empirical and provisional seed transfer zones for the Mojave Desert and surrounding regions
Microsatellite genotypes for desert tortoise (Gopherus agassizii) in Ivanpah Valley (2015-2017)
Microsatellite genotypes for desert tortoise (Gopherus agassizii) from scat (2016-2018)
Principal components of climate variation in the Desert Southwest (ver. 2.0, September 2019)
Local ecological niche models, genotype associations and environmental data for desert tortoises.
Principal components of climate variation in the Desert Southwest for the time periods 1980-2010, 2040-2070 (RCP8.5) and (RCP4.5)
Spatial predictions of habitat suitability for present-day (1950 - 2000 yr) and mid-Holocene (8.3 ka - 4.2 ka) time intervals
Dispersal limitations increase vulnerability under climate change for reptiles and amphibians in the southwestern United States
Demographic and environmental correlates of home ranges and long-distance movements of Mohave ground squirrels
Computed tomography for measuring body fat reserves in threatened Mohave desert tortoise (Gopherus agassizii)
What common-garden experiments tell us about climate responses in plants
Seed menus: An integrated decision-support framework for native plant restoration in the Mojave Desert
Protocol for route restoration in California’s desert renewable energy conservation plan area
A new species of Helianthus (Asteracae) from Clark County, Nevada
Integrating telemetry data at several scales with spatial capture–recapture to improve density estimates
Local climate adaptations in two ubiquitous Mojave Desert shrub species, Ambrosia dumosa and Larrea tridentata
Borreliosis transmission from ticks to humans associated with desert tortoise burrows: Examples of tick-borne relapsing fever in the Mojave Desert
Linking behavioral states to landscape features for improved conservation management
Assessment of disease risk associated with potential removal of anthropogenic barriers to Mojave desert tortoise (Gopherus agassizii) population connectivity
Mojave Seed Menus: a new spatial tool for restoration software release v1.0
Science and Products
WERC Fire ScienceWERC scientists are defining the past, present, and future of wildfires for wildlife and human communities. Explore this webpage to learn about specific, ongoing projects across California and parts of Nevada.
Aridlands Disturbances and Restoration EcologyDesert landscapes are rapidly changing due to increases in invasive plant species, frequency of wildfires, urban and energy development, recreational use, military training, and climate variation. Dr. Todd Esque, USGS researchers, and collaborators are working together to investigate these changes and provide managers with key information that can be used to manage natural resources more...
Ecology and Conservation of Golden Eagles in the Mojave DesertDr. Kathleen Longshore, in collaboration with Dr. Todd Esque, provides information to project the possible conflict between losses of habitat for foraging involved in the proposed development of alternative energy installations in the Mojave Desert and help develop advanced conservation efforts for the golden eagle. Information from this project will also inform California’s Desert Renewable...
Desert Tortoise Ecology, Health, Habitat, and Conservation BiologyThe desert tortoise is listed as “threatened” under the Endangered Species Act. USGS WERC scientists, along with project partners have been conducting long-term analyses on how changes in the southwestern deserts of the United States can affect desert tortoise populations. Dr. Todd Esque and his team are investigating how habitat disturbances and restoration projects influence tortoise populations...
Southwestern Desert Ecology of At-risk Species and their HabitatsThe southwestern desert region is home to many sensitive species. Species are at-risk due to past, present, and future changes to the landscape. WERC’s Dr. Todd Esque, field researchers, and collaborators are using models, monitoring plans, and decision-support tools to provide land managers with the resources they need to answer questions about how environmental change influences plants, animals...
Boulder City Field StationThe Boulder City Field Station supports research scientists leading projects in desert ecosystem restoration, genetics of iconic trees of the Mojave Desert, predator-prey studies on protected lands, and more. Select the next tab for a comprehensive summary of studies at this site.
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Ecological and Disease Data for Induced Immune Responses and Antibody Levels for Mycoplasma spp. in Captive and Wild Mojave Desert Tortoises (Gopherus agassizii)This product consists of multiple tabular datasets and associated metadata for clinical status, gene transcripts, and lab results related to presence of Mycoplasma spp. in desert reptiles. To better understand immune responses to pathogenic infections, we conducted an experiment to quantify innate and induced immune responses using gene transcript profiles and measured induced antibody levels for
Species Distribution Models for Native Species in the Mojave DesertPreserving native species diversity is fundamental to ecosystem conservation. Selecting appropriate native species for use in restoration is a critical component of project design and may emphasize species attributes such as life history, functional type, pollinator services, and nutritional value for wildlife. Determining which species are likely to establish and persist in a particular environme
Ecotypic Variation in Ambrosia dumosa and Larrea tridentata from Three Sites Across the Mojave (2014 - 2018)These data were acquired from two native Mojave Desert species, Ambrosia dumosa and Larrea tridentata, from 3 sites (50 m x 50 m garden plots) distributed across the differing Mojave Desert ecotones. These sites were located on the Fort Irwin National Training Center (CA), north of Joshua Tree National Park (CA), and north of Saint George (UT). Growth and survivorship data were collected monthly f
Mojave Desert Tortoise (Gopherus agassizii) Morphometrics and Egg Data from Seven Sites across the Mojave, (1997-2002)These data were acquired from 7 study sites distributed across the range of Gopherus agassizii. Data were collected from 1997 to 2002 as part of three separate studies, although data were not collected at all sites in each year. Radio-transmitters were attached to the carapace of 151 females and VHF radio-telemetry was used to relocate animals to assess reproductive status. Egg production was dete
Genetic and Habitat Data for Plantago ovata in the Mojave DesertThese datasets were developed to represent the genetic diversity, population structure, and geographic distribution of Plantago ovata in the Mojave Desert. This data release consists of two tab-delimited text files representing the genetic diversity and structure of Plantago ovata (.genepop and .vcf), and two raster spatial datasets (GeoTIFF) reflecting predicted habitat for the species within the
Empirical and provisional seed transfer zones for the Mojave Desert and surrounding regionsEmpirical evidence that local adaptation and home-site advantages are frequent across plant taxa has increased recognition that local adaptation plays a fundamental role in shaping plant responses to seed transfer (i.e., when plant materials are introduced to a site during restoration). Use of maladapted plant materials can lead to poor project outcomes if propagules exhibit poor germination or se
Microsatellite genotypes for desert tortoise (Gopherus agassizii) in Ivanpah Valley (2015-2017)These data show the multilocus genotypes, gender, and midline carapace length (MCL) for desert tortoises (Gopherus agassizii) sampled in the central portion of the Mojave desert tortoise range. This data supports the following publication: Dutcher, K.E., Vandergast, A.G., Esque, T.C., Mitelberg, A., Matocq, M.D., Heaton, J.S. and Nussear, K.E., Genes in space: what Mojave Desert tortoise g
Microsatellite genotypes for desert tortoise (Gopherus agassizii) from scat (2016-2018)These data show the multilocus genotypes, as well as extraction and sample genotype quality assessments for desert tortoise (Gopherus agassizii) scat samples. These data support the following publication: Mitelberg, A., Vandergast, A.G., Nussear, K.E., Dutcher, K. and Esque, T.C., 2019. Development of a Genotyping Protocol for Mojave Desert Tortoise Scat. Chelonian Conservation and Biology. ht
Principal components of climate variation in the Desert Southwest (ver. 2.0, September 2019)Five principal components are used to represent the climate variation in an original set of 12 climate variables reflecting precipitation and temperature gradients. The dataset provides coverage for four regions (the Sonoran Desert, Mojave Desert, Colorado Plateau, and Southern Great Basin) and three time periods including current climate (defined as the 1980-2010 normal period) and future climate
Local ecological niche models, genotype associations and environmental data for desert tortoises.These data include environmental covariates used to develop species distribution models for Gopherus agassizii and Gopherus morafkai, along with PCA-reduced environmental covariates used to explore local species-environment relationships within a subregion of the ectone between the two species. We also provide the genotype association used to test the mapped clusters of multiscale geographically w
Principal components of climate variation in the Desert Southwest for the time periods 1980-2010, 2040-2070 (RCP8.5) and (RCP4.5)Five principal components are used to represent the climate variation in an original set of 12 climate variables reflecting precipitation and temperature gradients. The dataset provides coverage for four regions (the Sonoran Desert, Mojave Desert, Colorado Plateau, and Southern Great Basin) and two time periods: current climate (defined as the 1980-2010 normal period) and future climate (defined a
Spatial predictions of habitat suitability for present-day (1950 - 2000 yr) and mid-Holocene (8.3 ka - 4.2 ka) time intervalsThis dataset provides spatial predictions of habitat suitability for current (1950 - 2000 yr) and mid-Holocene (8.3 ka - 4.2 ka) intervals using hindcasting, and three separate paleo-distributions calibrated on the packrat midden archive: those without bias correction (naive), those created with a standard method (standard), and those created with a novel alternative (modeled) incorporating a thre
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Dispersal limitations increase vulnerability under climate change for reptiles and amphibians in the southwestern United StatesSpecies conservation plans frequently rely on information that spans political and administrative boundaries, especially when predictions are needed of future habitat under climate change; however, most species conservation plans and their requisite predictions of future habitat are often limited in geographical scope. Moreover, dispersal constraints for species of concern are not often incorporat
Demographic and environmental correlates of home ranges and long-distance movements of Mohave ground squirrelsSpace use by mammals can differ among age-classes, sexes, or seasons, and these processes are recognized as adaptive behavioral strategies. Semi-fossorial ground squirrels, in particular, have shown age- and sex-specific patterns in their aboveground movement behaviors. We studied space use of Mohave ground squirrels (Xerospermophilus mohavensis) at the Freeman Gulch study site in the central regi
Computed tomography for measuring body fat reserves in threatened Mohave desert tortoise (Gopherus agassizii)Noninvasive methods for measuring fat reserves in both captive and free-ranging animals are important for monitoring individual and population health, but chelonian anatomy and physiology present challenges to accurate measurements. Standard field-based methods for assessing body condition in Mojave desert tortoises (Gopherus agassizii) involve the qualitative body condition score, which relies on
What common-garden experiments tell us about climate responses in plantsCommon garden experiments are indoor or outdoor plantings of species or populations collected from multiple distinct geographic locations, grown together under shared conditions. These experiments examine a range of questions for theory and application using a variety of methods for analysis. The eight papers of this special feature comprise a cross section of contemporary approaches, summarized a
Seed menus: An integrated decision-support framework for native plant restoration in the Mojave DesertThe combination of ecosystem stressors, rapid climate change, and increasing landscape-scale development has necessitated active restoration across large tracts of disturbed habitats in the arid southwestern United States. In this context, programmatic directives such as the National Seed Strategy for Rehabilitation and Restoration have increasingly emphasized improved restoration practices that p
Protocol for route restoration in California’s desert renewable energy conservation plan areaIn the deserts of the Southwestern United States, increased off-highway vehicle use can lead to widespread vehicular damage to desert ecosystems. As the popularity and intensity of vehicle use on public lands continues, the Bureau of Land Management (BLM) is challenged to manage the routes used by recreationists while minimizing activity beyond designated routes and mitigating environmental impact
A new species of Helianthus (Asteracae) from Clark County, NevadaHelianthus devernii T.M.Draper is described as a new endemic species from two small desert spring populations found within Red Rock Canyon National Conservation Area, Clark County, NV. Morphological data and nuclear ribosomal ITS marker data place it in section Ciliares series Pumili. Furthermore, the molecular data allies it most closely to H. pumilus Nutt. Helianthus devernii differs from H. pum
Integrating telemetry data at several scales with spatial capture–recapture to improve density estimatesAccurate population estimates are essential for monitoring and managing wildlife populations. Mark–recapture sampling methods have regularly been used to estimate population parameters for rare and cryptic species, including the federally listed Mojave desert tortoise (Gopherus agassizii); however, the methods employed are often plagued by violations of statistical assumptions, which have the pote
Local climate adaptations in two ubiquitous Mojave Desert shrub species, Ambrosia dumosa and Larrea tridentataWidely distributed species are often locally adapted to climate gradients across their ranges. But little is known about the patterns of intraspecific adaptation in desert shrubs.We examined the questions of local adaptation in multiple populations of two common shrub species of the winter-wet Mojave Desert in North America in a multiple common garden experiment. Plants were raised in the greenhou
Borreliosis transmission from ticks to humans associated with desert tortoise burrows: Examples of tick-borne relapsing fever in the Mojave DesertTicks transmit pathogens and parasitize wildlife in turn causing zoonotic diseases in many ecosystems. Argasid ticks, such as Ornithodoros spp., harbor and transmit Borrelia spp., resulting in tick-borne relapsing fever (TBRF) in people. In the western United States, TBRF is typically associated with the bite of an infected Ornithodoros hermsi tick found in habitats at high elevations (>1500 ft).
Linking behavioral states to landscape features for improved conservation managementA central theme for conservation is understanding how animals differentially use, and are affected by change in, the landscapes they inhabit. However, it has been challenging to develop conservation schemes for habitat-specific behaviors.Here we use behavioral change point analysis to identify behavioral states of golden eagles (Aquila chrysaetos) in the Sonoran and Mojave Deserts of the southwest
Assessment of disease risk associated with potential removal of anthropogenic barriers to Mojave desert tortoise (Gopherus agassizii) population connectivityThe Mojave Desert tortoise (Gopherus agassizii), federally listed as threatened, has suffered habitat loss and fragmentation due to human activities. Upper respiratory tract disease (URTD), a documented health threat to desert tortoises, has been detected at the Large-Scale Translocation Study Site (LSTS) in southwestern Nevada, US, a fenced recipient site for translocated animals. Our study aimed
Mojave Seed Menus: a new spatial tool for restoration software release v1.0Mojave Seed Menus is a spatial decision-support tool designed to help land managers create suitable seed mixes for restoration sites, such as a burned area or other mapped spatial feature. The application provides coverage for the Mojave Desert ecoregion. Seed menus are based on a combination of habitat suitability models for 50 priority restoration plant species. Species are selected based on the