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91 result(s) for "fecal genotyping"
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White-Tailed Deer Fawn Recruitment Before and After Experimental Coyote Removals in Central Georgia
Recent evidence from across the southeastern United States indicating high predation rates by coyotes (Canis latrans) on white-tailed deer (Odocoileus virginianus) fawns has led some managers to implement coyote control. Although some evidence suggests coyote control can improve recruitment, success appears to be site dependent. Therefore, we designed an experiment to assess feasibility of coyote control as a management action to increase recruitment on B.F. Grant and Cedar Creek Wildlife Management Areas (WMA) in central Georgia, USA. We estimated annual coyote abundance during 2010–2012 using a noninvasive mark–recapture design and fawn recruitment using infrared-triggered camera surveys. During March–June 2011 and March–April 2012, trappers removed coyotes from both sites. Estimates of coyote abundance on B.F. Grant WMA after trapping were 81% (2011) and 24% (2012) lower than during preremoval. Coyote abundance estimates were similar among years on Cedar Creek WMA. Fawn recruitment on B.F. Grant WMA averaged 0.65 fawns/adult female prior to removal and 1.01 fawns/adult female during the 2 years following the removals. Fawn recruitment on Cedar Creek WMA did not differ among years during the study, and was similar to that prior to coyote arrival. The differential coyote impacts and variable effectiveness of trapping we observed on nearby sites suggest coyote control may not achieve management objectives in some areas. Furthermore, transient behavior and the potential for coyotes to adapt to control efforts likely reduce efficacy of this management action. However, we observed an increase in recruitment on B.F. Grant WMA during one year, and others have seen similar responses. Therefore if lowered fawn recruitment is hindering achievement of management objectives, we recommend managers who opt to control coyotes continuously monitor recruitment to determine whether a response occurs.
Estimating gray wolf pack size and family relationships using noninvasive genetic sampling at rendezvous sites
Studying the ecology and behavior of pack animals often requires that most, or all, of the pack members are sampled. A unique opportunity to sample all gray wolf (Canis lupus) pack members arises during the summer months when reproductive packs localize in rendezvous sites. We collected 155–296 scat and hair samples from each of 5 wolf rendezvous sites in central Idaho to evaluate intrapack relationships and determine the efficacy of noninvasive genetic sampling (NGS) for estimating pack size and family relationships. We detected 65 wolves (5–20 wolves per pack) with NGS, and the pack counts from NGS were the same or higher for adults and the same or slightly lower for pups compared with the counts from observation and telemetry. The wolves in each pack were closely related to one another, and all packs included at least 2 years of offspring from the current breeding pair. Three of the packs had additional breeding adults present. In 1 pack pups were produced by a parent–offspring pair and a pair of their inbred full siblings, indicating multiple cases of inbreeding. This targeted NGS approach shows great promise for studying pack size and wolf social structure without the use of radiotelemetry or direct observations.
Identifying gray wolf packs and dispersers using noninvasive genetic samples
Many animals, including gray wolves (Canis lupus), live in social groups. Genetic techniques can help reveal the structure and composition of social groups, providing valuable information about group and population dynamics. We evaluated the effectiveness of using noninvasive genetic sampling (NGS) of fecal and hair samples at wolf rendezvous sites combined with spatial and genetic assignment criteria for assigning individuals to packs, detecting dispersers and lone wolves, determining the number of packs in an area, and obtaining group metrics. We applied this approach in 4 study areas covering 13,182 km² in Idaho, USA while concurrently monitoring wolves using telemetry techniques. We assigned pack affiliation to 78-97% of individuals across study areas and identified 12 potential dispersers. We detected a successful gene flow event by reconstructing a breeding male's genotype and tracing it back to a pack of origin using genetic assignment techniques. Average pack size was consistent between our NGS- and telemetry-based counts (x̄ = 10 for both), and both methods detected similar age composition within groups (31% pups and 69% adults for NGS and 33% pups and 67% adults for telemetry). Our NGS approach has the advantage of providing pack metrics including sex ratio, inferred breeders, and intra-pack relatedness that telemetry and observational techniques alone cannot. This NGS field sampling strategy combined with our pack assignment method was successful and provides an approach for characterizing functional social groups in the absence of previously acquired NGS, telemetry, or other observational data that may not be available when sampling new areas. © 2016 The Wildlife Society.
Efficacy and Precision of Fecal Genotyping to Estimate Coyote Abundance
Questions concerning the effects on other wildlife species by coyotes (Canis latrans) in recently colonized areas, including the southeastern United States, continue to receive attention in the literature. Coyote abundance estimates, achieved via genetic sampling of feces, can be useful in answering such questions. However, rapid degradation of fecal DNA in humid subtropical climates, like that of the southeastern United States, may limit the efficacy of the technique. To evaluate this hypothesis, we collected and analyzed 434 suspected coyote scats from February 2010 to April 2012 on 2 sites in central Georgia, USA. We quantified seasonal and comprehensive genotyping success, and the effect of sampling effort on precision of closed population abundance estimates. We successfully species-typed 316 (73%) scats, 219 (69%) of which belonged to coyotes. Of those, 136 (62%) yielded multilocus genotypes. The seasonal probability of genotyping a scat ranged from 0.53 to 0.71. Scats collected during spring were more likely to yield consensus genotypes, but the overall effect of season on genotyping success was minimal. The median CV formodel-averaged 𝑁̂ (i.e., coyote abundance) using the complete data set was relatively precise (<15%). Precision of abundance estimates decreased with decreasing sampling effort, but CV values remained <20% with up to a 25% reduction in effort. Our findings related to genotyping success demonstrate noninvasive genetic sampling of feces is a promising technique for estimating coyote abundance in humid subtropical climates. Combined with our results regarding sampling effort, these findings can aid in designing surveys capable of achieving desired objectives in similar environments.
Estimating size and trend of the North Interlake woodland caribou population using fecal-DNA and capture-recapture models
A critical step in recovery efforts for endangered and threatened species is the monitoring of population demographic parameters. As part of these efforts, we evaluated the use of fecal-DNA based capture—recapture methods to estimate population sizes and population rate of change for the North Interlake woodland caribou herd (Rangifer tarandus caribou), Manitoba, Canada. This herd is part of the boreal population of woodland caribou, listed as threatened under the federal Species at Risk Act (2003) and the provincial Manitoba Endangered Species Act (2006). Between 2004 and 2009 (9 surveys), we collected 1,080 fecal samples and identified 180 unique genotypes (102 females and 78 males). We used a robust design survey plan with 2 surveys in most years and analysed the data with Program MARK to estimate encounter rates (p), apparent survival rates (φ), rates of population change (λ), and population sizes (N). We estimated these demographic parameters for males and females and for 2 genetic clusters within the North Interlake. The population size estimates were larger for the Lower than the Upper North Interlake area and the proportion of males was lower in the Lower (33%) than the Upper North Interlake (49%). Population rate of change for the entire North Interlake area (2005—2009) using the robust design Pradel model was significantly <1.0 (λ = 0.90, 95% CI: 0.82—0.99) and varied between sex and area with the highest being for males in Lower North Interlake (λ = 0.98, 95% CI: 0.83—1.13) and the lowest being for females in Upper North Interlake (λ = 0.83,95% CI: 0.69—0.97). The additivity of λ between sex and area is supported on the log scale and translates into males having a λ that is 0.09 greater than females and independent of sex, Lower North Interlake having a λ that is 0.06 greater than Upper North Interlake. Population estimates paralleled these declining trends, which correspond to trends observed in other fragmented populations of woodland caribou along the southern part of their range. The results of this study clearly demonstrate the applicability and success of non-invasive genetic sampling in monitoring populations of woodland caribou.
Tracking the expansion of the American mink (Neovison vison) range in NW Portugal
Invasive in many European countries, the American mink (Neovison vison) was introduced in Portugal in the late 1980’s, presumably escaping from Spanish fur farms close to the border. In spite of the biological richness of the invaded area, no study ever addressed the evolution of the invasion process. We aimed to investigate the current distribution and status of the mink in NW Portugal and discuss some contributing factors to explain the rate of invasion. We detected mink presence using floating rafts as footprint tracking devices, and scats as a molecular tool aiding in species identification. Results demonstrate a clear range expansion southwards, with mink already occupying most of the region’s hydrographic basins. After a first phase of slow expansion (55 km in 20 years), mink seems to have expanded its range quite rapidly in only 2 years (45 km). The initial delay could be due to local thriving otter populations, whereas the recent establishment of red swamp crayfish (Procambarus clarkii) in the area could be a plausible explanation for the acceleration in the mink’s expansion. Being a key food resource, crayfish may be playing an important role as an expansion facilitator. Mink eradication is probably no longer feasible since well established populations near the border continue to function as sources for the Portuguese population. Therefore, a control program should start immediately in the NW region, preferably in conjunction with Spanish authorities.
Fecal genotyping reveals demographic variation in river otters inhabiting a contaminated environment
The deposition and accumulation of persistent contaminants into coastal systems can have lingering negative consequences for wildlife populations and their habitats. Using multi-locus genotyping of non-invasively collected feces, we assessed the effects of such pollution on reproduction, survival, genetic variability, and abundance of river otters (Lontra canadensis) along a gradient of urban—industrial development on southern Vancouver Island, British Columbia, Canada. Genetic analyses indicated a pattern consistent with small-scale structuring, with individuals partitioned into 2 local subpopulations—those identified in the contaminated harbors of southern Vancouver Island and points west (Colwood/Harbors), and those inhabiting uncontaminated habitat east of the harbors (Oak Bay). Genetic and demographic analyses for the 2 clusters provide strong support for the conclusion that, despite contamination concerns, Colwood/Harbors river otters exhibited acceptable levels of survival and successfully reproduced (i.e., high levels of relatedness, high self-recruitment, and high emigration). However, our data indicate that the Colwood/Harbors area constitutes lower quality habitat supporting lower densities of otters, especially during winter, and excess individuals produced in that region emigrate to other areas. Immigration into Colwood/Harbors, however, seems limited, possibly because of behavioral aversion of non-habituated otters to anthropogenic disturbance associated with the harbors and limited optimal otter habitat. Our findings suggest that the effects of chronic contaminant exposure at the population level may be inadvertently mitigated through the behavioral decisions of individuals to avoid poor quality habitats. We conclude that populations of river otters can persist in and around locally contaminated sites if relatively less disturbed and contaminated habitats remain in the vicinity of the affected areas.
Assessing individual patterns of Echinococcus multilocularis infection in urban coyotes: non‐invasive genetic sampling as an epidemiological tool
In epidemiological studies of wildlife parasites, faecal genotyping has been introduced to prevent bias in estimates of parasite prevalence from faecal samples collected in the field. Such an approach could be particularly relevant in the study of Echinococcus multilocularis transmission in urban settings, where estimates of prevalence and patterns of infection in wild canid hosts are key parameters used in zoonotic risk assessment and management. However, no previous study has evaluated the reliability of E. multilocularis faecal prevalence, and individual patterns of infection in definitive hosts remain poorly understood. We evaluated faecal genotyping as an epidemiological tool, using E. multilocularis in urban coyotes Canis latrans as our study system. Combining parasitological analysis and multilocus individual genotyping of coyote faeces, we compared faecal parasite prevalence with the prevalence obtained from genotyped faecal samples. Furthermore, we assessed patterns of individual infection, such as re‐infection rates and phenology of parasite egg excretion. Of 425 faeces collected in five urban sites, we genotyped 142 samples (33·4%) corresponding to 60 unique individual coyotes. Number of genotyped samples per coyote ranged between 1 and 10 (mean = 2·3). Genotypes were obtained at 4–6 microsatellite loci and had a mean reliability of 0·9975. Faecal prevalence of E. multilocularis in genotyped coyotes was 25·0%, and similar to results previously obtained from non‐genotyped faeces. Faecal genotyping allowed estimating a re‐infection rate of individual coyotes of 57·1% and to observe temporal patterns of parasite infection that were not detected using non‐genotyped faeces. Synthesis and applications. If compared to independent data obtained through coyote post‐mortem examination, our results suggest that reliable estimates of overall parasite prevalence in definitive host populations can be efficiently obtained through well‐designed field collection and traditional faecal parasitological analysis. However, faecal genotyping allows assessing the dynamics of individual infections, which could otherwise only be estimated by using invasive techniques. Combining faecal genotyping with parasitology has a great potential in assessing zoonotic risk transmission in urban areas, as well as advancing the field of wildlife ecology, disease ecology and conservation.
Feasibility and Recommendations for Swift Fox Fecal DNA Profiling
Genetic profiling using fecal samples collected noninvasively in the wild can provide managers with an alternative to live-trapping. However, before embarking on a large-scale survey, feasibility of this methodology should be assessed for the focal species. Costs associated with fecal genotyping can be high because of the need for multiple amplifications to prevent and detect errors. Assessing the relative amount of target DNA before genotyping means samples can be eliminated where error rates will be high or amplification success will be low, thereby reducing costs. We collected fecal samples from an endangered population of swift fox (Vulpes velox) and employed target-DNA quantification and a screening protocol to assess sample quality before genetic profiling. Quantification was critical in identifying samples of low quality (68%, <0.2 ng/µL). Comparison of the amplification, from a subset of loci in 25 samples that did not meet the screening criteria, confirmed the effectiveness of this method. The protocol, however, used a considerable amount of DNA, and an assessment of the locus and sample variability allowed us to refine it for future population surveys. Although we did not use >50% of the samples we collected, the remaining samples provided 36 unique genotypes, which corresponded to approximately 70% of animals estimated to be present in the study area. Although obtaining fecal DNA from small carnivores is challenging, our protocol, including the quantification and qualification of DNA, the selection of markers, and the use of postgenotyping analyses, such as DROPOUT, CAPWIRE, and geographic information, provides a more cost-effective way to produce reliable results. The method we have developed is an informative approach that wildlife managers can use to conduct population surveys where the collection of feces is possible without the need for live-trapping.
Snow Leopards: Is Reintroduction the Best Option?
This chapter contains sections titled: Summary Introduction Snow leopards as candidates for reintroduction The stocking source: captive‐ or wild‐bred? Would translocation help to resolve human‐wildlife conflict and to re‐populate depleted areas? The role of conservation in natural recolonization The importance of science‐based planning Conclusions References