Evaluating Survey Methods for Monitoring a Rare Vertebrate, the Sonoran Desert Tortoise

2010 ◽  
Vol 74 (6) ◽  
pp. 1311-1318 ◽  
Author(s):  
Erin R. Zylstra ◽  
Robert J. Steidl ◽  
Don E. Swann
Keyword(s):  
Sonoran Desert ◽  
Survey Methods ◽  
Desert Tortoise

Evaluating Survey Methods for Monitoring a Rare Vertebrate, the Sonoran Desert Tortoise

2010 ◽  
Vol 74 (6) ◽  
pp. 1311-1318 ◽  
Author(s):  
ERIN R. ZYLSTRA ◽  
ROBERT J. STEIDL ◽  
DON E. SWANN
Keyword(s):  
Sonoran Desert ◽  
Survey Methods ◽  
Desert Tortoise

Estimating the probability of illegal desert tortoise collection in the Sonoran Desert

2011 ◽  
Vol 76 (2) ◽  
pp. 262-268 ◽  
Author(s):  
David D. Grandmaison ◽  
Vincent J. Frary
Keyword(s):  
Sonoran Desert ◽  
Desert Tortoise

Case Study: Using Soil Survey to Help Predict Sonoran Desert Tortoise Population Distribution and Densities

Rangelands ◽  
2017 ◽  
Vol 39 (3-4) ◽  
pp. 97-111
Author(s):  
Robert D. Stager ◽  
Elno Roundy ◽  
Gary Brackley ◽  
Steve Leonard ◽  
Leon Lato
Keyword(s):  
Sonoran Desert ◽  
Population Distribution ◽  
Soil Survey ◽  
Desert Tortoise

scholarly journals Quantifying development to inform management of Mojave and Sonoran desert tortoise habitat in the American southwest

2020 ◽  
Vol 42 ◽  
pp. 167-184
Author(s):  
SK Carter ◽  
KE Nussear ◽  
TC Esque ◽  
IIF Leinwand ◽  
E Masters ◽  
...  
Keyword(s):  
Sonoran Desert ◽  
Mojave Desert ◽  
Spatial Scales ◽  
Public Lands ◽  
American Southwest ◽  
Federal State ◽  
Desert Tortoise ◽  
Multiple Use ◽  
State And Local ◽  
Development Levels

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 for both species occurs on multiple-use public lands, where development associated with traditional and renewable energy production, recreation, and other activities is likely to continue. Our goal was to quantify development to inform and evaluate actions implemented to protect and manage desert tortoise habitat. We quantified a landscape-level index of development across the Mojave and Sonoran desert tortoise ranges using models of potential habitat for each species (152485 total observations). We used 13 years of Mojave desert tortoise monitoring data (4732 observations) to inform the levels and spatial scales at which tortoises may be affected by development. Most (66-70%) desert tortoise habitat has some development within 1 km. Development levels on desert tortoise habitat are lower inside versus outside areas protected by actions at national, state, and local levels, suggesting that protection efforts may be having the desired effects and providing a needed baseline for future effectiveness evaluations. Of the relatively undeveloped desert tortoise habitat, 43% (74030 km2) occurs outside of existing protections. These lands are managed by multiple federal, state, and local entities and private landowners, and may provide opportunities for future land acquisition or protection, including as mitigation for energy development on public lands.

Enhancing and Restoring Habitat for the Desert Tortoise

2016 ◽  
Vol 7 (1) ◽  
pp. 255-279 ◽  
Author(s):  
Scott R. Abella ◽  
Kristin H. Berry
Keyword(s):  
Sonoran Desert ◽  
Mojave Desert ◽  
Native Species ◽  
Habitat Restoration ◽  
Management Practices ◽  
Soil Health ◽  
Forage Quality ◽  
Desert Tortoise ◽  
Forage Plants ◽  
Nonnative Grasses

AbstractHabitat has changed unfavorably during the past 150 y for the desert tortoise Gopherus agassizii, a federally threatened species with declining populations in the Mojave Desert and western Sonoran Desert. To support recovery efforts, we synthesized published information on relationships of desert tortoises with three habitat features (cover sites, forage, and soil) and candidate management practices for improving these features for tortoises. In addition to their role in soil health and facilitating recruitment of annual forage plants, shrubs are used by desert tortoises for cover and as sites for burrows. Outplanting greenhouse-grown seedlings, protected from herbivory, has successfully restored (>50% survival) a variety of shrubs on disturbed desert soils. Additionally, salvaging and reapplying topsoil using effective techniques is among the more ecologically beneficial ways to initiate plant recovery after severe disturbance. Through differences in biochemical composition and digestibility, some plant species provide better-quality forage than others. Desert tortoises selectively forage on particular annual and herbaceous perennial species (e.g., legumes), and forage selection shifts during the year as different plants grow or mature. Nonnative grasses provide low-quality forage and contribute fuel to spreading wildfires, which damage or kill shrubs that tortoises use for cover. Maintaining a diverse “menu” of native annual forbs and decreasing nonnative grasses are priorities for restoring most desert tortoise habitats. Reducing herbivory by nonnative animals, carefully timing herbicide applications, and strategically augmenting annual forage plants via seeding show promise for improving tortoise forage quality. Roads, another disturbance, negatively affect habitat in numerous ways (e.g., compacting soil, altering hydrology). Techniques such as recontouring road berms to reestablish drainage patterns, vertical mulching (“planting” dead plant material), and creating barriers to prevent trespasses can assist natural recovery on decommissioned backcountry roads. Most habitat enhancement efforts to date have focused on only one factor at a time (e.g., providing fencing) and have not included proactive restoration activities (e.g., planting native species on disturbed soils). A research and management priority in recovering desert tortoise habitats is implementing an integrated set of restorative habitat enhancements (e.g., reducing nonnative plants, improving forage quality, augmenting native perennial plants, and ameliorating altered hydrology) and monitoring short- and long-term indicators of habitat condition and the responses of desert tortoises to habitat restoration.

Fire Ecology of the Sonoran Desert Tortoise

2019 ◽  
pp. 312-333
Author(s):  
TODD C. ESQUE ◽  
ALBERTO BÚRQUEZ M. ◽  
CECIL R. SCHWALBE ◽  
THOMAS R. VAN DEVENDER ◽  
PAMELA J. ANNING ◽  
...  
Keyword(s):  
Sonoran Desert ◽  
Fire Ecology ◽  
Desert Tortoise

scholarly journals Enhancing Quality of Desert Tortoise Habitat: Augmenting Native Forage and Cover Plants

2015 ◽  
Vol 6 (2) ◽  
pp. 278-289 ◽  
Author(s):  
Scott R. Abella ◽  
Lindsay P. Chiquoine ◽  
E. Cayenne Engel ◽  
Katherine E. Kleinick ◽  
Fred S. Edwards
Keyword(s):  
Sonoran Desert ◽  
Average Density ◽  
First Year ◽  
Desert Tortoise ◽  
Forage Plants ◽  
Krascheninnikovia Lanata ◽  
Southern Nevada ◽  
Forage Species ◽  
Positive Effect

Abstract Vegetation in habitat of the federally listed desert tortoise Gopherus agassizii in the Mojave and western Sonoran Desert is now partly or mostly dominated by nonnative annual plants. To improve forage quality and augment availability of perennial cover plants, we tested seeding (pelletized or bare seeding), watering, and fencing for increasing a native annual forage species (desert plantain Plantago ovata), a perennial forage species (desert globemallow Sphaeralcea ambigua), and two shrub species (cheesebush Hymenoclea salsola and winterfat Krascheninnikovia lanata) that provide cover in desert tortoise habitat of southern Nevada. Treatments were ineffective at establishing the perennial species, even though greenhouse assays confirmed that some bare and pelletized seeds were germinable. In contrast, pelletized seeding quadrupled the density of desert plantain compared with not seeding or seeding untreated seed by the end of the first year (autumn 2013). Fencing tripled density of desert plantain to 17 plants/m2. Pelletized seeding plus fencing produced a desert plantain density of 39 plants/m2, the highest average density among all treatment combinations. The positive effect of fencing persisted until at least the second year after treatment (autumn 2014). Augmenting native annual forage plants favored by desert tortoises is feasible.

Feral Burros and Other Influences on Desert Tortoise Presence in the Western Sonoran Desert

Herpetologica ◽  
2020 ◽  
Vol 76 (4) ◽  
Author(s):  
Kristin H. Berry ◽  
Julie L. Yee ◽  
Lisa M. Lyren
Keyword(s):  
Sonoran Desert ◽  
Desert Tortoise
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