Department of Defense (DoD) installations in the Mojave Desert face conflict between installation mission (e.g., training and testing) and environmental compliance with regard to the federally and state listed Mojave Desert tortoise (Gopherus agassizii). The desert tortoise has low annual fecundity over a long lifespan with low and variable egg and hatchling survival. A gap exists in the knowledge base about desert tortoises because the smaller size/age cohorts are relatively unstudied and are difficult to locate during typical survey efforts involving humans using visual detection methods.  This project demonstrated the ability of Desert Tortoise Canine (DTK9) teams to locate Mojave Desert tortoises in the field at natural population densities, with an emphasis on finding small size classes. Performance objectives were evaluated in each of two phases conducted in southern Nevada: Phase I involved baseline characterization at the Desert Tortoise Conservation Center (DTCC), and Phase II consisted of a field demonstration at Piute Valley. The objective of Phase I was to demonstrate that DTK9 teams can pass a testing regime that assesses their capability at finding tortoises under both high and low tortoise density scenarios with tortoise safety maintained throughout. Phase II was intended to demonstrate that teams deemed qualified to conduct field searches for tortoises based on meeting Phase I testing criteria performed similarly in the field; whereas, those teams that failed to meet the testing criteria did not perform to standard in the field.

Technology Description

The U.S. military has played and continues to play an active role in developing working dog applications, particularly for detection. Recent dog detection advancements for military and homeland security applications include improvised explosive devices and identifying humans that have been in contact with bomb-making materials or are wearing explosive devices. The DTK9 program drew upon this type of training applied to non-lethal targets. Dogs use olfaction to detect desert tortoises, which lends an orthogonal approach to visual methods currently employed in surveys. They can be trained to sniff and alert on odors within their threshold of detection, including live animals. The demonstration design established DTK9 capability by comparing results from field survey deployments against baseline assessments. Deployment parameters and a certification standard for DTK9 teams also were established.

Demonstration Results

Phase I included three different tests: safety, high density tortoise scenario, and low density tortoise scenario. Quantitative metrics included threshold scores for safety, based on nine different behaviors, and for efficacy and reliability. Behavioral measures of safety included aggression (defensive and overt), excessive flight, play interaction, growling, barking, stalking, excessive focus, and inability to relax in the presence of tortoises. Efficacy is the number of targets (e.g., tortoises) found of the total available to be found. Reliability is the number of trained alerts performed by the dog divided by the total number of targets found. Both metrics are calculated based on the first encounter with a particular tortoise. Taken together, efficacy and reliability are a capability metric of a team. For the high density scenario, a minimum efficacy of 70% and minimum reliability of 75% were required. For the low density scenario, the teams were scored as pass/fail. Handlers were required to maintain safety at all times for all tests and were required to use the in-field calibration method the project termed “Read-and-Go.” All teams passed the safety test. Six of the seven teams passed the high density scenario and six passed the low density scenario. In total, five teams passed all three assessments and two teams failed the testing criteria.

All teams were then fielded for the Phase II demonstration conducted on a population of wild, transmittered desert tortoises supplemented with transmittered small tortoises in Piute Valley within desert tortoise critical habitat. Teams were not informed of their Phase I testing results and believed they had all passed. This was done to minimize handler belief bias in the field demonstration. Performance assessment was based on finding three size classes of tortoises: small (<110 mm median carapace length [MCL]), medium (110–180 mm MCL) and large (>180 mm MCL). The required efficacies to pass the assessment for these classes were 50%, 60%, and 70%, respectively with reliability of 75% for all size classes. The five teams that passed Phase I tests yielded 78% (small), 96% (medium), and 100% (large) efficacy and 90% reliability. The two teams that failed Phase I yielded 14% (small), 50% (medium), and 75% (large) efficacy and 55% reliability.

The testing procedures implemented in Phase I produced teams that were capable of safely and successfully surveying for desert tortoises in natural field conditions, across all size classes at expected natural densities. It was also demonstrated that the testing procedures would have eliminated teams that did not perform to required standards in the field environment. Thus, the testing procedures were indicated to be valid and relevant.

Implementation Issues

The benefits of DTK9 teams over current practices to survey for Mojave Desert tortoises include demonstrated ability to locate the full range of size classes and in particular small animals, a greater find rate for tortoises in certain configurations, efficiency in survey area coverage, and cost. Currently, desert tortoise surveys are conducted by humans using visual methods such as mirrors and probe poles. Humans have not returned reliable find rates for tortoises smaller than 180 mm MCL and thus current range-wide surveys conducted by the U.S. Fish and Wildlife Service do not include data on smaller animals. DTK9 teams can assist in collecting that data and, in so doing, enable accurate and complete population estimates, life tables, and demographic analyses.

Implementation of DTK9 teams rests in part on acceptance of the proposed certification standard by the federal and state regulatory (permitting) agencies. Discussion and review of the standards are ongoing with these agencies. Once the process is approved, the use of DTK9 teams can be implemented in the same manner as for human surveys. Contractors are expected to provide the primary source of DTK9 teams; however, DoD installations could easily develop in-house capabilities given the widespread acceptance and use of dogs for other military applications.

  • Habitat ,

  • Mojave