BackgroundMajority of the tiger habitat in Indian subcontinent lies within high human density landscapes and is highly sensitive to surrounding pressures. These forests are unable to sustain healthy tiger populations within a tiger-hostile matrix, despite considerable conservation efforts. Ranthambore Tiger Reserve (RTR) in Northwest India is one such isolated forest which is rapidly losing its links with other tiger territories in the Central Indian landscape. Non-invasive genetic sampling for individual identification is a potent technique to understand the relationships between threatened tiger populations in degraded habitats. This study is an attempt to establish tiger movement across a fragmented landscape between RTR and its neighboring forests, Kuno-Palpur Wildlife Sanctuary (KPWLS) and Madhav National Park (MNP) based on non-invasively obtained genetic data.MethodsData from twelve microsatellite loci was used to define population structure and also to identify first generation migrants and admixed individuals in the above forests.ResultsPopulation structure was consistent with the Central Indian landscape and we could determine significant gene flow between RTR and MNP. We could identify individuals of admixed ancestry in both these forests, as well as first generation migrants from RTR to KPWLS and MNP.ConclusionsOur results indicate reproductive mixing between animals of RTR and MNP in the recent past and migration of animals even today, despite fragmentation and poaching risk, from RTR towards MNP. Substantial conservation efforts should be made to maintain connectivity between these two subpopulations and also higher protection status should be conferred on Madhav National Park.
BackgroundNon-invasively collected samples allow a variety of genetic studies on endangered and elusive species. However due to low amplification success and high genotyping error rates fewer samples can be identified up to the individual level. Number of PCRs needed to obtain reliable genotypes also noticeably increase.MethodsWe developed a quantitative PCR assay to measure and grade amplifiable nuclear DNA in feline faecal extracts. We determined DNA degradation in experimentally aged faecal samples and tested a suite of pre-PCR protocols to considerably improve DNA retrieval.ResultsAverage DNA concentrations of Grade I, II and III extracts were 982pg/µl, 9.5pg/µl and 0.4pg/µl respectively. Nearly 10% of extracts had no amplifiable DNA. Microsatellite PCR success and allelic dropout rates were 92% and 1.5% in Grade I, 79% and 5% in Grade II, and 54% and 16% in Grade III respectively. Our results on experimentally aged faecal samples showed that ageing has a significant effect on quantity and quality of amplifiable DNA (p<0.001). Maximum DNA degradation occurs within 3 days of exposure to direct sunlight. DNA concentrations of Day 1 samples stored by ethanol and silica methods for a month varied significantly from fresh Day 1 extracts (p<0.1 and p<0.001). This difference was not significant when samples were preserved by two-step method (p>0.05). DNA concentrations of fresh tiger and leopard faecal extracts without addition of carrier RNA were 816.5pg/µl (±115.5) and 690.1pg/µl (±207.1), while concentrations with addition of carrier RNA were 49414.5pg/µl (±9370.6) and 20982.7pg/µl (±6835.8) respectively.ConclusionsOur results indicate that carnivore faecal samples should be collected as freshly as possible, are better preserved by two-step method and should be extracted with addition of carrier RNA. We recommend quantification of template DNA as this facilitates several downstream protocols.
BackgroundTiger populations are dwindling rapidly making it increasingly difficult to study their dispersal and mating behaviour in the wild, more so tiger being a secretive and solitary carnivore.MethodsWe used non-invasively obtained genetic data to establish the presence of 28 tigers, 22 females and 6 males, within the core area of Pench tiger reserve, Madhya Pradesh. This data was evaluated along with spatial autocorrelation and relatedness analyses to understand patterns of dispersal and philopatry in tigers within this well-managed and healthy tiger habitat in India.ResultsWe established male-biased dispersal and female philopatry in tigers and reiterated this finding with multiple analyses. Females show positive correlation up to 7 kms (which corresponds to an area of approximately 160 km2) however this correlation is significantly positive only upto 4 kms, or 50 km2 (r = 0.129, p<0.0125). Males do not exhibit any significant correlation in any of the distance classes within the forest (upto 300 km2). We also show evidence of female dispersal upto 26 kms in this landscape.ConclusionsAnimal movements are important for fitness, reproductive success, genetic diversity and gene exchange among populations. In light of the current endangered status of tigers in the world, this study will help us understand tiger behavior and movement. Our findings also have important implications for better management of habitats and interconnecting corridors to save this charismatic species.
Tiger, being a solitary and territorial animal, often tends to move out of protected areas into the surrounding forests. This is especially true in the case of subadult animals leading to escalating conflicts and deaths in the surrounding human-dominated landscapes. Unless adequately protected against various human activities, such corridors and surrounding forests will soon disappear, trapping the animals within protected areas with resultant local extinctions. In this paper we ascertain tiger presence, occupancy and numbers in one such partially protected area, the Sathyamangalam forest, located close to better known tiger reserves in India, through non-invasive faecal DNA analysis. Here we highlight the potential of Sathyamangalam as a tiger habitat. Tiger positive faecal samples were considered as evidence to establish occupancy in two different parts of Sathyamangalam, reserve forest and wildlife sanctuary. We collected 103 faecal samples out of which 69 were tiger positive. Species occupancy (psi), was 0.672 (±0.197) with a detection probability of 0.2 (±0.06) in the wildlife sanctuary area; while psi was 0.72 (±0.2) with detection probability of 0.212 (±0.6) in the reserve forest. Further, number of males and females, as determined in our study, was close to the ideal sex ratio in a healthy forest with good prey abundance. This study also highlights the presence of more females in the reserve forest (n = 10) than the wildlife sanctuary (n = 3) possibly indicating lesser disturbance and more prey availability. We recommend that the reserve forest to the north of Sathyamangalam wildlife sanctuary be declared as a tiger reserve. The wildlife sanctuary could serve as a buffer zone between this reserve and Sathyamangalam town which lies to the south of the forest. Proper protection of Sathyamangalam will go a long way in saving the entire landscape and tigers of the Western Ghats of India.
Translocations of large carnivores like tiger to restore extirpated populations are increasingly becoming important conservation tools in the face of persistent anthropogenic pressures and relentless habitat loss. Reintroduction success in Panna Tiger Reserve, India was variously attributed to high genetic diversity, less anthropogenic disturbance and stress, efficient execution and technological integrations. Here, we establish parentage relationships and explore the potential of mate choice and appropriate adult sex ratio to explain the successful reintroduction in Panna. We used a combination of radio‐telemetry and genetic analyses to understand mating interactions of translocated tigers and their outcomes. Surprisingly, relatedness and parentage analyses of nine cubs born in 2010–2012 suggested that five cubs (55.5%) were not sired by the single translocated male tiger, emphasizing the difficulty of assessing the persistence of tiger presence over a large geographic area. Genotype data of tigers originally from Panna prior to the present reintroduced population revealed that four cubs were sired by an original Panna tiger which possibly ranged transiently within the released tigers’ home ranges. Presence of additional male for mate choice can be a strong factor for successful reintroduction of tigers in Panna. Although number of females released is a good indicator of reintroduction success, the number of males released is also a very important factor for success. We hypothesize that while tigers live in female‐dominated population structure within male territories, mate selection strategies operate strongly between sexes. Translocation programs should therefore deliberate on this aspect of mate selection and accordingly consider founder compositions to achieve desirable results. This also reinforces the need for post‐release monitoring and thorough investigations into intraspecific interactions and behavior which will facilitate proper management and revival of tiger populations.
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