Detection dogs allow for systematic non-invasive collection of DNA samples from Eurasian lynx

Conservation detection dogs: A critical review of efficacy and methodology

Conservation detection dogs (CDD) use their exceptional olfactory abilities to assist a wide range of conservation projects through the detection of target specimens or species. CDD are generally quicker, can cover wider areas and find more samples than humans and other analytical tools. However, their efficacy varies between studies; methodological and procedural standardisation in the field is lacking. Considering the cost of deploying a CDD team and the limited financial resources within conservation, it is vital that their performance is quantified and reliable. This review aims to summarise what is currently known about the use of scent detection dogs in conservation and elucidate which factors affect efficacy. We describe the efficacy of CDD across species and situational contexts like training and fieldwork. Reported sensitivities (i.e. the proportion of target samples found out of total available) ranged from 23.8% to 100% and precision rates (i.e. proportion of alerts that are true positives) from 27% to 100%. CDD are consistently shown to be better than other techniques, but performance varies substantially across the literature. There is no consistent difference in efficacy between training, testing and fieldwork, hence we need to understand the factors affecting this. We highlight the key variables that can alter CDD performance. External effects include target odour, training methods, sample management, search methodology, environment and the CDD handler. Internal effects include dog breed, personality, diet, age and health. Unfortunately, much of the research fails to provide adequate information on the dogs, handlers, training, experience and samples. This results in an inability to determine precisely why an individual study has high or low efficacy. It is clear that CDDs can be effective and applied to possibly limitless conservation scenarios, but moving forward researchers must provide more consistent and detailed methodologies so that comparisons can be conducted, results are more easily replicated and progress can be made in standardising CDD work.

Sampling and modelling rare species: Conceptual guidelines for the neglected majority

Biodiversity conservation faces a methodological conundrum: Biodiversity measurement often relies on species, most of which are rare at various scales, especially prone to extinction under global change, but also the most challenging to sample and model. Predicting the distribution change of rare species using conventional species distribution models is challenging because rare species are hardly captured by most survey systems. When enough data are available, predictions are usually spatially biased towards locations where the species is most likely to occur, violating the assumptions of many modelling frameworks. Workflows to predict and eventually map rare species distributions imply important trade-offs between data quantity, quality, representativeness and model complexity that need to be considered prior to survey and analysis. Our opinion is that study designs need to carefully integrate the different steps, from species sampling to modelling, in accordance with the different types of rarity and available data in order to improve our capacity for sound assessment and prediction of rare species distribution. In this article, we summarize and comment on how different categories of species rarity lead to different types of occurrence and distribution data depending on choices made during the survey process, namely the spatial distribution of samples (where to sample) and the sampling protocol in each selected location (how to sample). We then clarify which species distribution models are suitable depending on the different types of distribution data (how to model). Among others, for most rarity forms, we highlight the insights from systematic species-targeted sampling coupled with hierarchical models that allow correcting for overdispersion and spatial and sampling sources of bias. Our article provides scientists and practitioners with a much-needed guide through the ever-increasing diversity of methodological developments to improve the prediction of rare species distribution depending on rarity type and available data.

Eyes, ears, or nose? Comparison of three non-invasive methods to survey wolf recolonisation

The development and use of cost-effective and appropriate survey methods to assess species distribution and to monitor range expansion and contraction of wild populations is crucial due to the limited financial resources for conservation. Of particular importance, yet little studied, is the ability to collect information before a wild population is well established, i.e. at the early stages of recolonisation. During 2018 and 2019, we used camera traps, audio recorders, and scat detection dogs simultaneously to investigate composition, detection probability, and territorial extent of a pack of wolves in the Swiss Alps. We compared the efficacy of these survey methods by assessing sampling effort, data obtained, and costs. We show that, under the presented setup, camera traps and scat detection dogs substantially outperformed audio recorders in detecting wolves, representing the packs’ territorial extent, and revealing the number of adult wolves. The detection dogs did not detect pups but, unlike the other methods, allowed the identification of single individuals. The use of four camera traps during 13 weeks, a 24-km-long transect walked with the detection dog, or the use of one audio recorder during 148 weeks were necessary to obtain a comparable wolf detection probability. Our results show that no single method was able to return all information that we hoped to collect. Comprehensive and cost-effective information was best obtained by combining data from camera traps and detection dogs. We suggest both methods to be simultaneously used to successfully investigate wolf recolonisation into historical range.

The Promise of Genetics and Genomics for Improving Invasive Mammal Management on Islands

Invasive species are major contributors to global biodiversity decline. Invasive mammalian species (IMS), in particular, have profound negative effects in island systems that contain disproportionally high levels of species richness and endemism. The eradication and control of IMS have become important conservation tools for managing species invasions on islands, yet these management operations are often subject to failure due to knowledge gaps surrounding species- and system-specific characteristics, including invasion pathways and contemporary migration patterns. Here, we synthesize the literature on ways in which genetic and genomic tools have effectively informed IMS management on islands, specifically associated with the development and modification of biosecurity protocols, and the design and implementation of eradication and control programs. In spite of their demonstrated utility, we then explore the challenges that are preventing genetics and genomics from being implemented more frequently in IMS management operations from both academic and non-academic perspectives, and suggest possible solutions for breaking down these barriers. Finally, we discuss the potential application of genome editing to the future management of invasive species on islands, including the current state of the field and why islands may be effective targets for this emerging technology.

How quoll-ified are northern and spotted-tailed quoll detection dogs?

Abstract ContextWildlife detection dogs have been used globally in environmental monitoring. However, their effectiveness in the Australian context has been only minimally researched. Increased understanding of detection dog accuracy and efficacy is required for their inclusion in survey guidelines used by proponents of referred actions potentially impacting Australia’s threatened mammals. Evaluation of new methods is also important for advancing population monitoring, particularly for threatened species. AimsTo determine the efficacy of wildlife detection dogs as a survey tool for low-density, cryptic species, using northern (Dasyurus hallucatus) and spotted-tailed (D. maculatus) quolls as subjects. We compared detection dogs, human search effort and camera trapping results, in simulated accuracy and efficacy trials, and field surveys. MethodsTwo wildlife detection dogs’ scores for sensitivity (ability to identify a target species scat) and specificity (ability to distinguish target from non-target species scats) were calculated during accuracy trials. The dogs were tested using 288 samples, of which 32 were targets, where northern and spotted-tailed quoll scat were the targets in separate trials. Survey efficacy was determined following completing 12 simulated surveys (6 per target species) involving a single, randomly placed scat sample in a 1–1.5ha search area. During the northern quoll simulated surveys the dogs’ survey efficacy was compared with that of a human surveyor. The dogs also undertook field surveys for both northern and spotted-tailed quolls, in conjunction with camera trapping for comparison. Key resultsDuring accuracy trials the dogs had an average sensitivity and specificity respectively of 100% and 98.4% for northern quoll, and 100% and 98% for spotted-tailed quoll. Their average search time in efficacy trials for northern quoll was 11.07min (significantly faster than the human surveyor), and 2.98min for spotted-tailed quoll in the 1–1.5ha search areas. During field surveys, northern quoll scats were detected at sites where camera trapping failed to determine their presence. No spotted-tailed quoll scat was detected by the dogs during field surveys. ConclusionsTrained and experienced detection dogs can work very accurately and efficiently, which is vital to their field success. Detection dogs are therefore capable of detecting evidence of species presence where alternative methods may be unsuccessful. ImplicationsOur study supports the future use of highly trained detection dogs for wildlife surveys and monitoring in Australia. Our results demonstrate that detection dogs can be highly accurate and are a beneficial stand-alone or complimentary method.

The rise of a large carnivore population in Central Europe: genetic evaluation of lynx reintroduction in the Harz Mountains

Large carnivores have made a successful comeback across human-dominated landscapes in Central Europe. The Eurasian lynx, for instance, has been actively reintroduced in different regions. Genetic diversity is quickly eroding in these isolated, small populations, questioning the long-term success of lynx reintroductions. To track population development and genetic diversity in a reintroduced lynx population, we used microsatellite analysis and mtDNA haplotyping based on 379 samples collected during the initial 15 year period of lynx reintroduction in the Harz mountains National Park, Germany. The Harz lynx population shows higher genetic diversity relative to other lynx reintroductions, due to initial cross-breeding of divergent captive source lineages and a comparably high founder size. While the population shows significant population growth and spread into adjacent regions, genetic diversity is continiously declining. Expected heterozygosity values dropped from 0.63 after reintroduction (2006/2007) to 0.55 within a 10 year period. Despite this, the Harz lynx population is currently a viable component to an envisioned lynx metapopulation spanning across Central Europe. The ongoing genetic erosion in the Harz population along with a lack of geneflow from adjacent populations indicates that such connectivity is urgently needed to ensure long-term population persistence.