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
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
Henderson Field Station
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
Microsatellite genotypes for desert tortoise (Gopherus agassizii) in Ivanpah Valley (2015-2017)
Microsatellite genotypes for desert tortoise (Gopherus agassizii) from scat (2016-2018)
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
Golden Eagle Food Habits in the Mojave Desert: Regional information for a changing landscape.
Estimates of pathogen exposure predict varying transmission likelihood: Host contact and shedding patterns may clarify disease dynamics in desert tortoises Gopherus agassizii
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
Priority species lists to restore desert tortoise and pollinator habitats in Mojave Desert shrublands
Connectivity of Mojave Desert tortoise populations—Management implications for maintaining a viable recovery network
Comparing sample bias correction methods for species distribution modeling using virtual species
‘Unscrambling’ the drivers of egg production in Agassiz’s desert tortoise: Climate and individual attributes predict reproductive output
Using movement to inform conservation corridor design for Mojave desert tortoise
Mojave Seed Menus: a new spatial tool for restoration software release v1.0
Science and Products
- Science
WERC Fire Science
WERC 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 Ecology
Desert 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 Desert
Dr. 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 Biology
The 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 Habitats
The 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...Henderson Field Station
The Henderson 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. - Data
Species Distribution Models for Native Species in the Mojave Desert
Preserving 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 environmeEcotypic 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 fMojave 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 deteGenetic and Habitat Data for Plantago ovata in the Mojave Desert
These 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 theMicrosatellite 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 gMicrosatellite 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. htLocal 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 wPrincipal 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 aSpatial predictions of habitat suitability for present-day (1950 - 2000 yr) and mid-Holocene (8.3 ka - 4.2 ka) time intervals
This 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 threGolden Eagle Food Habits in the Mojave Desert: Regional information for a changing landscape.
Expansion of renewable energy development is rapidly transforming the Mojave Desert landscape and has the potential to impact Golden Eagles through loss of foraging habitat and reduced prey base. Regional information on Golden Eagle food habits is limited and little is known of how dietary variability influences eagle productivity. We examined diet using motion activated trail cameras and collectiEstimates of pathogen exposure predict varying transmission likelihood: Host contact and shedding patterns may clarify disease dynamics in desert tortoises Gopherus agassizii
These datasets (S1-S4) document the transmission of a bacterial pathogen (Mycoplasma agassizii) between desert tortoises (Gopherus agassizii). The desert tortoises were experimentally introduced in captivity and were used to create and compare models predicting transmission probability given data on the hosts and their interactions. Datasets S1 & S2 include variables describing the individ - Multimedia
- Publications
Filter Total Items: 130
Protocol for route restoration in California’s desert renewable energy conservation plan area
In 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 impactA new species of Helianthus (Asteracae) from Clark County, Nevada
Helianthus 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. pumIntegrating telemetry data at several scales with spatial capture–recapture to improve density estimates
Accurate 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 poteLocal climate adaptations in two ubiquitous Mojave Desert shrub species, Ambrosia dumosa and Larrea tridentata
Widely 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 greenhouBorreliosis transmission from ticks to humans associated with desert tortoise burrows: Examples of tick-borne relapsing fever in the Mojave Desert
Ticks 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 management
A 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 southwestAssessment of disease risk associated with potential removal of anthropogenic barriers to Mojave desert tortoise (Gopherus agassizii) population connectivity
The 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 aimedPriority species lists to restore desert tortoise and pollinator habitats in Mojave Desert shrublands
Mojave Desert shrublands are home to unique plants and wildlife and are experiencing rapid habitat change due to unprecedented large-scale disturbances; yet, established practices to effectively restore disturbed landscapes are not well developed. A priority species list of native plant taxa was developed to guide seed collectors, commercial growers, resource managers, and restoration practitionerConnectivity of Mojave Desert tortoise populations—Management implications for maintaining a viable recovery network
Executive SummaryThe historic distribution of Mojave desert tortoises (Gopherus agassizii) was relatively continuous across the range, and the importance of tortoise habitat outside of designated tortoise conservation areas (TCAs) to recovery has long been recognized for its contributions to supporting gene flow between TCAs and to minimizing impacts and edge effects within TCAs. However, connectiComparing sample bias correction methods for species distribution modeling using virtual species
A key assumption in species distribution modeling (SDM) with presence‐background (PB) methods is that sampling of occurrence localities is unbiased and that any sampling bias is proportional to the background distribution of environmental covariates. This assumption is rarely met when SDM practitioners rely on federated museum records from natural history collections for geo‐located occurrences du‘Unscrambling’ the drivers of egg production in Agassiz’s desert tortoise: Climate and individual attributes predict reproductive output
ABSTRACT: The ‘bet hedging’ life history strategy of long-lived iteroparous species reduces short-term reproductive output to minimize the risk of reproductive failure over a lifetime. For desert-dwelling ectotherms living in variable and unpredictable environments, reproductive output is further influenced by precipitation and temperature via effects on food availability and limits on activity. WUsing movement to inform conservation corridor design for Mojave desert tortoise
BackgroundPreserving corridors for movement and gene flow among populations can assist in the recovery of threatened and endangered species. As human activity continues to fragment habitats, characterizing natural corridors is important in establishing and maintaining connectivity corridors within the anthropogenic development matrix. The Mojave desert tortoise (Gopherus agassizii) is a threatened - News
- Software
Mojave Seed Menus: a new spatial tool for restoration software release v1.0
Mojave 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