Specially trained detection dogs have been used to locate faeces (scats) for faecal analyses but their effectiveness has not been quantified. We evaluated detection and accuracy rates of dogs trained to find scats of endangered San Joaquin kit foxes (Vulpes macrotis mutica). Four dogs found from 0.43 to 5.37 presumptive kit fox scats per km of transect searched in two field sites where kit foxes and coyotes (Canis latrans) but not non-native red foxes (V. vulpes) were present. The unusually low detection rate (0.43 scats per km) by one dog (probably due to excessive panting in hot weather) was still similar to the average scat detection rate of two experienced humans. DNA tests of 1298 scats showed that all dogs were 100% accurate at distinguishing kit fox scats under our field conditions. Because red foxes are sympatric with kit foxes in some areas, we also conducted controlled discrimination experiments to see if trained dogs could distinguish between scats from kit and red foxes. Four dogs were 100% accurate at choosing a kit fox scat when red fox scats were present (n = 64 trials), but were less accurate at ignoring red fox scats in trials where a kit fox scat was absent.
Surveys using conservation detection dogs have grown increasingly popular as an efficient means to gather monitoring data, particularly for elusive and low‐density species such as carnivores. Working with dogs can greatly increase the area surveyed for wildlife and the detection rate of survey targets. Due to the confounding effects of scent dispersion and dog movement, however, it can be difficult to estimate the area searched in a survey. Additionally, although detection dogs have been used in studies under a wide range of air temperature, humidity, and wind conditions, little research has examined how environmental factors affect detection dogs' effectiveness for wildlife surveys. Between 2003 and 2005, we trained 2 dogs to assist us with surveys for mammalian carnivore scats in northern California. We conducted controlled search trials to assess how the dogs' scat detection rates were affected by the distance of scats from the transect search line, as well as variation in six environmental factors. Both dogs detected >75% of scats located within 10 m, and the dogs' detection rates decreased with increasing distance of scats from the transect line. Among environmental factors, precipitation was the most important variable explaining variation in scat detection rates for both dogs. Precipitation likely degrades or removes scats from the landscape over time, and detection rates increase as scat begins to accumulate following the last substantial (>5 mm) rain event of the year. If scat accumulation is not controlled for in ecosystems with a strong seasonal pattern of rainfall, it could lead to considerable bias in study results. We recommend that researchers report the conditions under which conservation detection dog surveys took place and analyze how detection rates vary as a function of distance, temperature, precipitation, humidity, wind, and other locally important environmental factors. © 2010 The Wildlife Society.
No abstract
Noninvasive faecal DNA sampling has the potential to provide a wealth of information necessary for monitoring and managing endangered species while eliminating the need to capture, handle or observe rare individuals. However, scoring problems, and subsequent genotyping errors, associated with this monitoring method remain a great concern as they can lead to misidentification of individuals and biased estimates. We examined a kit fox scat data set (353 scats; 80 genotypes) for genotyping errors using both genetic and GIS analyses, and evaluated the feasibility of combining both approaches to assess reliability of the faecal DNA results. We further checked the appropriateness of using faecal genotypes to study kit fox populations by describing information about foxes that we could deduce from the 'acceptable' scat genotypes, and comparing it to information gathered with traditional field techniques. Overall, genetic tests indicated that our data set had a low rate of genotyping error. Furthermore, examination of distributions of scat locations confirmed our data set was relatively error free. We found that analysing information on sex primer consistency and scat locations provided a useful assessment of scat genotype error, and greatly limited the amount of additional laboratory work that was needed to identify potentially 'false' scores. 'Acceptable' scat genotypes revealed information on sex ratio, relatedness, fox movement patterns, latrine use, and size of home range. Results from genetic and field data were consistent, supporting the conclusion that our data set had a very low rate of genotyping error and that this noninvasive method is a reliable approach for monitoring kit foxes.
We compared the effectiveness and cost of distribution surveys using livetrapping to those using detection dog-handler teams for a cryptic rodent (Franklin's ground squirrel [Poliocitellus franklinii]). We livetrapped at 62 sites in Illinois, Indiana, Iowa, Missouri, and Wisconsin for Franklin's ground squirrels in 2007-2009 and surveyed 40 of those sites using detection dogs in 2009. Independent surveys of a site by 2 dog-handler teams took <1 hr and yielded detection rates comparable to 2 daily livetrapping surveys (detection rate ¼ 83-84%). However, false presences are a potential problem when detection dogs are trained to scent of a species that leaves little visual sign to confirm its presence. Surveys by 2 dog-handler teams cost >2 daily livetrapping surveys conducted by 2 technicians but more and larger sites can be surveyed by dog-handler teams in a shorter time. For surveys covering large spatial scales or when time is a limiting factor, number of false presences, and study costs can be reduced by employing a 2-stage survey protocol in which livetrapping is conducted only at sites where detection dog surveys indicate presence. We conclude a 2-stage strategy could be used effectively in large-scale surveys for a variety of rare and cryptic species. ß 2011 The Wildlife Society.
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