‘Video‐scats’: combining camera trapping and non‐invasive genotyping to assess individual identity and hybrid status in gray wolf

Canu, Antonio; Mattioli, Luca; Santini, Alberto; Apollonio, Marco; Scandura, Massimo

doi:10.2981/wlb.00355

Cited by 15 publications

(25 citation statements)

References 46 publications

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“…During the study, 19 scats deposited by wolves in front of an active camera trap (“video-scats”) were collected and successfully genotyped. They produced 13 different genotypes corresponding to seven males and six females [ 34 ]. On the basis of video analysis, 10 wolves defecating at camera traps were classified as α individuals (see Additional file 1 ).…”

Section: Resultsmentioning

confidence: 99%

“…(Bologna, Italy). The laboratory genetic procedure is reported by Canu et al [ 34 ] and can be summarized as follows: i ) DNA was isolated from fecal material using a commercial kit; ii ) 11 polymorphic autosomal microsatellites were PCR-amplified in triplicates following a multi-tube approach; iii ) alleles were scored by running PCR products in an automatic sequencer; iv ) consensus genotypes were reconstructed from replicated multilocus genotypes; v ) sex was diagnosed genetically; vi ) genotypes were compared with a database including all genotypes obtained during the ongoing long-term NGS monitoring in the area, with the aim to identify wolves already sampled in previous occasions; vii) all wolf genotypes obtained in the area were tested for parentage in order to identify mating pairs and their offspring for each sampling year.…”

Section: Methodsmentioning

confidence: 99%

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Estimation of pack density in grey wolf (Canis lupus) by applying spatially explicit capture-recapture models to camera trap data supported by genetic monitoring

Mattioli¹,

Canu

Passilongo

et al. 2018

Front Zool

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BackgroundDensity estimation is a key issue in wildlife management but is particularly challenging and labour-intensive for elusive species. Recently developed approaches based on remotely collected data and capture-recapture models, though representing a valid alternative to more traditional methods, have found little application to species with limited morphological variation. We implemented a camera trap capture-recapture study to survey wolf packs in a 560-km2 area of Central Italy. Individual recognition of focal animals (alpha) in the packs was possible by relying on morphological and behavioural traits and was validated by non-invasive genotyping and inter-observer agreement tests. Two types (Bayesian and likelihood-based) of spatially explicit capture-recapture (SCR) models were fitted on wolf pack capture histories, thus obtaining an estimation of pack density in the area.ResultsIn two sessions of camera trapping surveys (2014 and 2015), we detected a maximum of 12 wolf packs. A Bayesian model implementing a half-normal detection function without a trap-specific response provided the most robust result, corresponding to a density of 1.21 ± 0.27 packs/100 km2 in 2015. Average pack size varied from 3.40 (summer 2014, excluding pups and lone-transient wolves) to 4.17 (late winter-spring 2015, excluding lone-transient wolves).ConclusionsWe applied for the first time a camera-based SCR approach in wolves, providing the first robust estimate of wolf pack density for an area of Italy. We showed that this method is applicable to wolves under the following conditions: i) the existence of sufficient phenotypic/behavioural variation and the recognition of focal individuals (i.e. alpha, verified by non-invasive genotyping); ii) the investigated area is sufficiently large to include a minimum number of packs (ideally 10); iii) a pilot study is carried out to pursue an adequate sampling design and to train operators on individual wolf recognition. We believe that replicating this approach in other areas can allow for an assessment of density variation across the wolf range and would provide a reliable reference parameter for ecological studies.Electronic supplementary materialThe online version of this article (10.1186/s12983-018-0281-x) contains supplementary material, which is available to authorized users.

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Section: Resultsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Estimation of pack density in grey wolf (Canis lupus) by applying spatially explicit capture-recapture models to camera trap data supported by genetic monitoring

Mattioli¹,

Canu

Passilongo

et al. 2018

Front Zool

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“…Nonetheless, these percentages of admixed individuals cannot be intended as estimates of prevalence of admixed individuals in the Italian wolf population because the analysed samples had not been randomly collected, but mostly derived from specific monitoring projects focused on hybrid detection and from heterogeneously monitored areas 26,31,33,52,56 . Conversely, reliable estimates of hybridization prevalence could be assessed through statistical multi-event models applied to capture-recapture data obtained from well-planned long-term genetic and camera-trapping monitoring projects carried out through the entire Italian wolf distribution range [79][80][81] .…”

Section: Discussionmentioning

confidence: 99%

“…Conversely, dog-derived phenotypic traits, though validated by robust phenotype-genotype association tests 26 , when found in operational pure individuals should not be considered sufficient reasons for any intervention, since they might reflect old introgression events. Nonetheless they could represent useful clues for identifying potential hybrids with preliminary field surveying methods, such as camera trapping 79,80,83 , to be followed by further careful genetic investigations.…”

Section: Discussionmentioning

confidence: 99%

A standardized approach to empirically define reliable assignment thresholds and appropriate management categories in deeply introgressed populations

Caniglia

Galaverni

Velli

et al. 2020

Sci Rep

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Anthropogenic hybridization is recognized as a major threat to the long-term survival of natural populations. While identifying F1 hybrids might be simple, the detection of older admixed individuals is far from trivial and it is still debated whether they should be targets of management. Examples of anthropogenic hybridization have been described between wolves and domestic dogs, with numerous cases detected in the Italian wolf population. After selecting appropriate wild and domestic reference populations, we used empirical and simulated 39-autosomal microsatellite genotypes, Bayesian assignment and performance analyses to develop a workflow to detect different levels of wolf x dog admixture. Membership proportions to the wild cluster (q iw ) and performance indexes identified two qthresholds which allowed to efficiently classify the analysed genotypes into three assignment classes: pure (with no or negligible domestic ancestry), older admixed (with a marginal domestic ancestry) and recent admixed (with a clearly detectable domestic ancestry) animals. Based on their potential to spread domestic variants, such classes were used to define three corresponding management categories: operational pure, introgressed and operational hybrid individuals. Our multiple-criteria approach can help wildlife managers and decision makers in more efficiently targeting the available resources for the long-term conservation of species threatened by anthropogenic hybridization.Over the last decades, thanks to the growing availability of genetic and genomic data, hybridization has been increasingly studied for its evolutionary and conservational implications on the long-term survival of the involved taxa 1-5 . However, while natural hybridization between closely related taxa is frequently acknowledged as an evolutionary process providing novel adaptive gene assemblages 6,7 , anthropogenic hybridization (AH), mainly caused by intentional admixture, translocations, habitat modifications and climate changes 8-10 , is globally considered a serious conservation threat to the genetic integrity of local populations, which might be compromised by gene introgression from alien or domesticated species [11][12][13][14][15][16] . Thus, the consequences of such human-mediated process should be continuously monitored to evaluate their real effects on the viability of natural populations 5,17 .However, to date, even in the era of genomics 4,18 , the concept of hybrid itself is rather fleeting and, consequently, legal status and management of hybrids are often poorly regulated by national and international laws, hampering the conservation of endangered species 12,14,[19][20][21][22]

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“…The camera trap approach is a non-invasive method for obtaining reliable mark-recapture data and it has been widely used in studies of rare or elusive terrestrial carnivores in order to minimize the disturbance caused by monitoring efforts (e.g., [ 54 – 56 ]). Although mark-recapture population estimation methods have been used recently with a few pinniped species [ 31 – 35 , 57 ], and have been in use for a longer time with cetaceans (e.g.,[ 58 – 60 ]), this is to the best of our knowledge the first project using camera-trapping for marine mammals to take place on such a large scale and also the first mark-recapture project to provide population estimates for a species of ringed seal.…”

Section: Discussionmentioning

confidence: 99%

A mark–recapture approach for estimating population size of the endangered ringed seal (Phoca hispida saimensis)

et al. 2019

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Reliable population estimates are fundamental to the conservation of endangered species. We evaluate here the use of photo-identification (photo-ID) and mark-recapture techniques for estimating the population size of the endangered Saimaa ringed seal (Phoca hispida saimensis). Photo-ID data based on the unique pelage patterns of individuals were collected by means of camera traps and boat-based surveys during the molting season in two of the species’ main breeding areas, over a period of five years in the Pihlajavesi basin and eight years in the Haukivesi basin. An open model approach provided minimum population estimates for these two basins. The results indicated high survival rates and site fidelity among the adult seals. More accurate estimates can be obtained in the future by increasing the surveying effort both spatially and temporally. The method presented here proved effective for evaluating population size objectively, whereas the results of the current snow lair censuses are dependent on varying winter conditions, for instance. We therefore suggest that a photo-ID-based non-invasive mark-recapture method should be used for estimating Saimaa ringed seal abundances in order to ensure reliable, transparent population monitoring under changing climatic conditions.

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‘Video‐scats’: combining camera trapping and non‐invasive genotyping to assess individual identity and hybrid status in gray wolf

Cited by 15 publications

References 46 publications

Estimation of pack density in grey wolf (Canis lupus) by applying spatially explicit capture-recapture models to camera trap data supported by genetic monitoring

Estimation of pack density in grey wolf (Canis lupus) by applying spatially explicit capture-recapture models to camera trap data supported by genetic monitoring

A standardized approach to empirically define reliable assignment thresholds and appropriate management categories in deeply introgressed populations

A mark–recapture approach for estimating population size of the endangered ringed seal (Phoca hispida saimensis)

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