Tiger Research Articles

Tigers at higher elevations outside their range: What does it mean for conservation?

Nepal’s population of endangered Bengal tigers (Panthera tigris) is on the rise. In recent years, the presence of tigers has been documented at higher elevations. The objective of this study is to explore the possible reasons for the tigers’ presence at the higher elevations. It is critical that these high-altitude habitats for tigers be further explored and protected. The study points out the importance of the Mahabharat range and a longitudinal conservation gradient approach in Nepal. Apart from this, it is imperative to assess the density of tigers and tiger prey in the area. Even though high-altitude ecology may be suitable for tiger growth, the formulation of a high-altitude tiger conservation action plan with effective coordination between stakeholder organizations and concerned departments is of great importance.

Malignant Snare Traps Threaten an Irreplaceable Megafauna Community

Tropical forests are under severe threat from over-hunting. Subsistence harvests and poaching have decimated wildlife populations to the extent that nearly 50% of Earth’s tropical forests are partially or fully devoid of large mammals. Declines are particularly acute in Southeast Asia where ongoing defaunation, largely attributable to indiscriminate snare trapping, is widespread. Using the extensively forested Aceh province in northern Sumatra as a case study, we document rampant snaring, which threatens Earth’s last sympatric population of tigers, rhinoceros, elephants, and orangutans. To prevent catastrophic hunting-induced impacts already experienced in mainland Southeast Asia, we call for more comprehensive conservation planning assessments that strengthen wildlife law enforcement, promote collaborative anti-poaching, and research species-specific snaring impacts, particularly in the context of human-wildlife conflict. We conclude with a discussion of the important linkages between poaching, wildlife trade, and zoonotic disease risk.

基于目标检测的东北虎个体自动识别

东北虎个体的自动识别是种群数量评估和制定有效保护策略的重要基础。以东北虎林园和怪坡虎园38 只虎为研究对象，将目标检测方法首次应用到东北虎个体识别研究中，采用多种深度卷积神经网络模型，以实现虎个体的自动识别。首先通过相机在不同角度对 38 只东北虎进行拍摄取样，建立包含13579张图像的虎样本数据集。由于虎的体侧条纹信息不具有对称性，所以运用单次多盒目标检测（Single Shot MultiBox Detector， SSD）方法，对虎的躯干左侧条纹、右侧条纹以及脸部等不同部位图像，进行自动检测并分割提取，极大节省手工截取时间。在检测分割出的左右侧及脸部不同部位图片基础上，运用上、下、左、右平移变换进行数据增强，使图片数目扩大为原来的5 倍。采用LeNet、AlexNet、ZFNet、VGG16、ResNet34共5 种卷积神经网络模型进行个体自动识别。为了提高识别准确率，运用平均值和最大值不同组合方式来优化池化操作，并在全连接层引入概率分别为0.1、0.2、0.3、0.4的丢弃（Dropout）操作防止过拟合。实验表明，目标检测模型耗时较少，截取分割老虎不同部位条纹能达到0.6 s/张，远快于人工截取速度，并且在测试集上准确率能达到97.4%。不同姿态下的目标部位都能正确识别并分割。ResNet34模型的准确率优于其他网络模型，左右侧条纹以及脸部图像识别准确率分别为93.75%、97.01%和 86.28%，右侧条纹识别准确率优于左侧条纹和脸部图像。研究为野生虎自动相机影像的识别提供技术参考。在未来研究中，对东北虎个体影响数据进行扩充，选取更多影像数据进行训练，使网络具有更强的适应性，从而实现更准确的个体识别。;The automaticly individual identification of Amur tigers (Panthera tigris altaica) is important for population monitoring and making effective conservation strategies. In this paper, we applied the object detection method and deep convolutional neural network models to individual identification with the images of 38 Amur tigers in the Northeast Tiger Forest Park (West 126°36', North 45°49') and Guaipo Tiger Park (West 123°37', North 42°4'). Firstly, the Canon EOS 200D camera was used to establish the data set containing 13579 pictures of Amur tiger from different angles. Since the tiger's body stripes of two sides are not symmetrical, single shot multibox detector (SSD) was used to automatically intercept and distinguish the left and right body stripes as well as the face of tiger, which greatly saved the time of manual interception. On the basis of the interception image results, the data were enhanced to 5 times by the up, down, left and right transformation. Then, LeNet, AlexNet, ZFNet, VGG16 and ResNet34 were used for individual identification. Furthermore, the pooling model was optimized by using different combinations of average pooling and maximum pooling, and the dropout operations with probabilities of 0.1, 0.2, 0.3 and 0.4 were introduced to prevent overfitting. The experiment shows that the target detection model in this study takes less time than manual interception. It can intercept and segment the stripes in different parts of the tiger with 0.6 seconds for one image, which is much faster than manual interception, and the accuracy rate on the test set can reach up to 97.4%. The target parts can be correctly identified and segmented for Amur tiger images with different kinds of positions. Finally, based on the experiment results, we found that the accuracy of ResNet34 is better than that of other network models. The recognition accuracies of left, right stripe and face images are 93.75%, 97.01%, and 86.28%, respectively. The recognition accuracy of right stripes is better than left stripes and face parts. This study can provide technical support for automatic camera image recognition of wild tigers. The method in this paper can be applied to the identification of individual in the species which have distinct streaks or spots on the body. In the future work, the image dadaset of individual Amur tigers will be expanded and much more image data will be selected for training set so as to make the network more adaptable and realize more accurate individual identification.

From “Mayo” Pete to Joe Exotic: HowTiger KingTaught Us How to be Queer Again

From “Mayo” Pete to Joe Exotic: HowTiger KingTaught Us How to be Queer Again

Comparison of the Morphology and Developmental Potential of Oocytes Obtained from Prepubertal and Adult Domestic and Wild Cats.

Simple SummaryThis study was conducted with the aim of determining the morphological similarities and developmental potential of oocytes obtained from adult and prepubertal domestic cats (Felis catus) and wild cats. The results of our research showed that ovaries obtained from prepubertal felids may be a rich source of good quality oocytes that are competent for in vitro maturation and able to reach blastocyst stage after in vitro fertilization. The results are important in the context of the possibility of using oocytes from prepubertal felids threatened with extinction in conservation programs based on assisted reproductive techniques (ART).The aim of the study was to compare the morphology and developmental potential of oocytes obtained from adult and prepubertal domestic cats (Felis catus) and wild cats (Lynx lynx, Leptailurus serval, Felis manul, Panthera tigris altaica). The average number of oocytes obtained from an adult domestic cat was 23 ± 11, which was significantly lower than from kittens (43 ± 29). A similar number of oocytes was derived from adult Pallas’s cats (28 ± 8), and serval (30). The lowest number of oocytes was collected from the lynx (5 ± 3). No oocytes were obtained from newborn Amur tiger while in the case of older domestic and Pallas’s cat and lynx kittens (1–3 months) 43, 48 and 41 oocytes were collected, respectively. Significant differences (p < 0.001) were observed between the number of oocytes with dark cytoplasm from adult and prepubertal animals of all analyzed species. The diameter of oocytes from adult and prepubertal animals was similar in all species, and was on average 161 ± 4 µm for oocytes with dark cytoplasm and 150 ± 18 µm for oocytes with light cytoplasm. In all species, oocytes with light cytoplasm were significantly smaller (p < 0.05) than dark ones, and their population was more diverse. Results of in vitro maturation of the domestic and wild cat′s oocytes obtained from adult and prepubertal females were similar (47–52%). The cleavage rate after in vitro fertilization (IVF) was lower for prepubertal than adult domestic cats (42 vs. 51%; p < 0.05%). Moreover, we observed differences in the quantity (28 vs. 39%; p < 0.05) and quality of blastocysts and even greater problems with hatching blastocysts from prepubertal kittens (8 vs. 19%; p < 0.001). More blastomeres were detected in blastocysts of adult cats. They also demonstrated significantly higher number of inner cell mass (ICM) (p < 0.001) and higher number of trophoblast cells (TE) (p < 0.05).

Population Estimate, Habitat-Use and Activity Patterns of the Honey Badger in a Dry-Deciduous Forest of Central India

Studies on carnivores are skewed toward larger species in India, limiting ecological information of the smaller ones. Basic ecological understanding like population density, distribution, habitat-use patterns of small carnivores is lacking. This inadequate knowledge has led to disagreement between conservation approaches in different landscapes. Honey badgers (Mellivora capensis) are cryptic carnivores distributed across large areas of Africa and Asia; however, fundamental ecological knowledge is scarce. The species is thought to exist at low population densities throughout its range. We used a large camera trap dataset from a tiger reserve in Maharashtra State, India to understand the population density, habitat preference, and diel activity pattern of the species. We applied an extension of the spatial count model for the estimation of population. Habitat preference analyses were carried out using generalized linear models and activity patterns were analyzed using kernel-density functions. The population density was estimated as 14.09 (95% CI 10–22.25) individuals per 100 km2. Habitat use revealed a positive association with forest cover and negative association with elevation. This may expose the species to other large carnivores in the habitat but honey badger activity pattern peaked at midnight retaining minimum temporal overlap with other large carnivores (e.g., tiger Panthera tigris, leopard Panthera pardus, and dhole Cuon alpinus) and moderate overlap with small carnivores (e.g., jungle cat Felis chaus, rusty-spotted cat Prionailurus rubiginosus). These behaviors, in turn, may facilitate the coexistence of species at such high density even with high carnivore density. We hope the findings of this study will fill the existing knowledge gap of this species and aid in guiding the conservation of the species in other landscapes and reserves.

Haematological and Biochemical Parameters of Captive Siberian Tigers (Panthera tigris altaica) from the Heilongjiang Province, China.

Haematological and biochemical parameters play important roles in safeguarding animal health and preventing disease, but the blood reference values of many wild animals are still unknown. Recently, few descriptions of the blood parameters of Siberian tigers (Panthera tigris altaica) have been reported because these tigers comprise an endangered species; however, it is extremely difficult to obtain blood samples necessary for these analyses. This study presents 14 haematological and 16 biochemical parameters of 133 Siberian tigers, of which 112 and 21 were from Heilongjiang Siberian Tiger Park (HB) and Hailin Siberian Tiger Park (HD), China, respectively. Our study is the first to determine the following parameters in Siberian tigers: red blood cell volume distribution width, platelet count, mean platelet volume, amylase (AMY), sodium/potassium, globulin and albumin/globulin levels. As the data for total bilirubin and AMY were not statistically significant, no statistical analysis was conducted for these parameters. Few parameters were significantly different according to sex and region (p < 0.05). The concentration of alkaline phosphatase decreased with age, whereas the creatinine (CREA) increased with age. The CREA concentration of tigers raised in HB was much lower than that of tigers raised in HD. The data obtained in this study provide a reference for monitoring the health of wild and captive Siberian tigers and will add important information to the standards for haematological and biochemical parameters of wild felines.

The Structure of Potential Amur Tiger (Panthera tigris altaica) Habitats and Evaluation of Its Prey in Taipingou National Reserve (China) Based on Remote Sensing Data

The population of the Amur tiger (Panthera tigris altaica) in the Russian Far East is currently being restored; young individuals are being spread within the historical range, including territory in China. Here, the assessment of the suitability for the territories that exist in Northeastern China as the Amur tiger habitat and its food supply-prey base (three species of ungulates, namely wild boar, red deer and roe deer) are shown. A specially protected area—the Taipingou Natural Reserve, located on the border of the People’s Republic of China and Russia—was examined. The modelling of habitat suitability for ungulates was performed on the basis of Earth remote sensing data by using two different approaches: expert geo-information assessment of the territory and discriminant analysis modelling. Based on discriminant analysis, the modelling of the suitability of ungulate habitats (without the variability of plant communities) showed a small difference between the model results for wild boar and roe deer. Nevertheless, the connection with the morphometric characteristics of the relief was more important for the wild boar than the roe deer. Furthermore, the variability of vegetation types was more important for the roe deer. The analysis of the biotopes showed that wild boars prefer the central and northern parts of Taipingou National Reserve, while the main roe deer distribution is in the western part of the Reserve; red deer are more common in the southern part of the Reserve.

Distemper, extinction, and vaccination of the Amur tiger

Canine distemper virus (CDV) has recently emerged as an extinction threat for the endangered Amur tiger (Panthera tigris altaica). CDV is vaccine-preventable, and control strategies could require vaccination of domestic dogs and/or wildlife populations. However, vaccination of endangered wildlife remains controversial, which has led to a focus on interventions in domestic dogs, often assumed to be the source of infection. Effective decision making requires an understanding of the true reservoir dynamics, which poses substantial challenges in remote areas with diverse host communities. We carried out serological, demographic, and phylogenetic studies of dog and wildlife populations in the Russian Far East to show that a number of wildlife species are more important than dogs, both in maintaining CDV and as sources of infection for tigers. Critically, therefore, because CDV circulates among multiple wildlife sources, dog vaccination alone would not be effective at protecting tigers. We show, however, that low-coverage vaccination of tigers themselves is feasible and would produce substantive reductions in extinction risks. Vaccination of endangered wildlife provides a valuable component of conservation strategies for endangered species.

Inferring patterns of sympatry among large carnivores in Manas National Park – a prey‐rich habitat influenced by anthropogenic disturbances

AbstractInferring the mechanisms that facilitate sympatry amongst large mammalian carnivores in anthropogenically altered habitats is critical if conservation initiatives aimed to recover populations are to be effective. In this study, we assessed the utilization of space, time and prey resources by tigers Panthera tigris, leopards P. pardus and dholes Cuon alpinus in Manas National Park (MNP), India – a site where prey densities are not limiting, yet anthropogenic influences alter the spatial and temporal behaviour of prey. We use photographic capture data and predator scats collected over three sampling years (2014–15, 2015–16 and 2016–17) to assess patterns of (a) spatial use using a multispecies species occupancy framework, (b) time–activity patterns and overlap between predators and prey using non‐parametric circular kernel‐density functions, (c) fine‐scale spatio‐temporal behaviour by comparing time‐to‐encounters of subsequent events and (d) predator diets by analysing prey remains in predator scats. Our results highlight that the predators segregate through fine‐scale spatio‐temporal avoidance rather than displaying population‐level changes in space‐use, activity patterns or food habits. Overlap in space‐use between tigers and leopards was high and time–activity patterns of the predators closely matched those of prey, suggesting that predators likely maximize resource acquisition in this prey‐rich environment. Ungulate prey dominated the diet of predators, resulting in the high dietary overlap. From our results, we infer patterns of sympatry among large carnivores in the face of anthropogenic influences and highlight the need to understand interspecific interactions within a community before initiating conservation actions aimed at recovering these endangered species.

Assessing the adequacy of a protected area network in conserving a wide‐ranging apex predator: The case for tiger (Panthera tigris) conservation in Bhutan

AbstractProtected area networks (PAN) are essential for conserving wide‐ranging apex predators but their adequacy in species protection has rarely been assessed. Here, we assess the adequacy of Bhutan's PAN in conserving and providing connectivity to the endangered tiger (Panthera tigris). We determine the current extent of tiger habitat, predict new suitable habitat, identify potential corridors, and empirically estimate the range of tiger numbers that Bhutan can spatially support. We use two spatial models with different approaches to ascertain current tiger distribution and predict new suitable tiger areas: (a) an expert model based on tiger ecology and (b) an observation model from observed tiger distribution. The expert model identified more suitable tiger areas (32,887 km2) over the observation model (29,962 km2), with the PAN encompassing 46% and 45% of predicted suitable areas, respectively. Vast suitable tiger habitat remains unprotected. Based on our estimates of total suitable habitats, Bhutan can spatially support 138–151 tigers compared to the current estimate of 103, thereby precluding a doubling in tiger numbers. To ensure adequate protection of tigers in Bhutan, we recommend readjusting and/or expanding existing PAN boundaries, including the designation of new corridors, protecting habitats, and conserving prey populations.

Patterns of livestock predation risk by large carnivores in India’s Eastern and Western Ghats

Large scale spatial patterns of livestock predation risk from multiple co-predators are fundamental to applied conservation planning. Here, we examined important ecological, social, and landscape attributes explaining spatial patterns of human-carnivore interactions. We used a systematic grid-based framework, across an area of 14,200 km2 of sixteen Forest Divisions at the human-wildlife interface encompassing Protected Areas, Reserved Forest and Fringe Areas at the human-wildlife interface in the Eastern and Western Ghats, India. The data was collected on livestock depredation incidents from the tiger (Panthera tigris), leopard (Panthera pardus), and dhole (Cuon alpinus) for the past five years, through semi-structured interviews (n = 1460) of local communities. We examined socio-ecological (i.e. livestock abundance and forest dependency) and landscape attributes (i.e. forest cover, climates and topographic) influencing the depredation events from each carnivore species. We found that livestock predation risk by the tiger, leopard and dhole was driven by the size of livestock species, the dependency of local people on the forest, topography, proximity to water body and the forest boundary, precipitation, and forest cover. Risk of predation from leopard and dhole exhibited high spatial overlap, and predation by leopards was higher than dhole and tiger. Livestock predation by leopard and dhole was frequent in open areas of Reserved Forest and buffer zones, while that from tiger occurred in densely forested core regions of Protected Areas (PAs). Our predictive risk maps (ca. 22,525 km2) showed species-specific predation patterns, reflected ecological differences among large carnivores with regards to their habitat and spatial partitioning for domestic prey. Our predictive predation risk map and factors associated with livestock predations provides powerful visual guidance and tools for PA managers in developing multi-species conflict mitigation strategies. We recommend diversifying local economic livelihoods and benefit-sharing options for local communities to minimize their forest dependency.

HISTOPLASMOSIS IN NONDOMESTIC FELIDS: A REVIEW OF SIX CASES

One adult leopard (Panthera pardus) and five adult tigers (Panthera tigris) presented with a range of nonspecific clinical signs, including lethargy (6/6), mobility deficits (4/6), and hyporexia (3/6). Hematology and biochemistry revealed a hyperproteinemia characterized by hyperglobulinemia (4/6), hepatocellular enzyme activity increases (3/6), azotemia (3/6), leukocytosis (2/6), hyperbilirubinemia (2/6), or a combination of conditions. Further diagnostics and management varied with the presenting signs and clinicopathological findings, including supportive care, diagnostic imaging, and blastomyces urine antigen analyses. Two animals died, and four were euthanatized. Postmortem findings included granulomatous pneumonia (6/6), fibrinous pleural effusion (3/ 6), pericardial effusion (2/6), and diffuse icterus (1/6). Histopathology revealed round to oval structures with a thin clear wall and purple inclusions within cells of the mononuclear phagocyte system, consistent with Histoplasma capsulatum, in each animal. Disseminated histoplasmosis was found in five cases, with organisms present in the lung (5/5), liver (3/5), lymph nodes (3/5), spleen (2/5), bone marrow (2/5), thyroid (1/5), tongue (1/ 5), kidney (1/5), or a combination of organs. One tiger was found to have pulmonary histoplasmosis without evidence of disseminated infection. On the basis of clinical and pathological findings, histoplasmosis was diagnosed. This case series illustrates the difficulties in antemortem diagnosis of histoplasmosis on the basis of complete blood count, serum biochemistry profile, and antigen testing and underscores that histoplasmosis should be considered a differential diagnosis in any felid presenting with nonspecific clinical signs in endemic areas.

THE EFFECTS OF PROCEDURE DURATION AND ATIPAMEZOLE ADMINISTRATION ON HYPERKALEMIA IN TIGERS (PANTHERA TIGRIS) AND LIONS (PANTHERA LEO) ANESTHETIZED WITH α-2 AGONISTS.

A retrospective analysis of 40 extended (>2 hr) anesthetic events in eight lions (Panthera leo) and 32 tigers (Panthera tigris) was performed using a hierarchical linear growth curve model to assess the effects of anesthetic time, α-2 adrenoreceptor agonist dosages, administration of atipamezole, and biochemical parameters on rising plasma K+ concentrations. Hyperkalemia was first noted at a mean time of 187 min (range: 131-226 min), with time under anesthesia as a statistically significant predictor of K+ concentration (P < 0.0001). A significant two-way interaction between time and atipamezole administration (P = 0.0082) for rising K+ concentrations was demonstrated, indicating that administration of atipamezole can mitigate the rise in K+ concentrations. Administration of atipamezole beyond 150 min of anesthetic time was less effective in reducing K+ concentrations than if administered earlier. Electrocardiographic abnormalities were noted in eight animals, including three hyperkalemic individuals. Lions developed significantly greater plasma K+ concentrations than tigers (P = 0.0009) during anesthesia. No biochemical parameter was identified as a significant indicator of which individuals will develop hyperkalemia. Clinicians anesthetizing any large nondomestic felid should monitor electrolytes regularly during anesthetic events; consider early, partial- to full-dose reversal of α-2 agonists; and be prepared to correct potentially life-threatening electrocardiographic abnormalities resulting from hyperkalemia.

HISTOLOGIC EVIDENCE OF SPONTANEOUS OVULATION IN TIGERS (PANTHERA TIGRIS).

Spontaneous ovulation has been identified in several wild felid species and domestic cats previously thought to undergo only induced ovulation. Two studies have assessed ovulation patterns in tigers (Panthera tigris) and have not found evidence of spontaneous ovulation in this species. However, uterine pathology typically associated with prolonged progesterone exposure has been identified in unbred tigers, suggesting spontaneous ovulation occurs. Ovaries from 47 tigers were reviewed with histologic examination. The presence or lack of active corpora lutea was documented and compared with social housing conditions for each animal. Social housing categories were as follows: female housed alone, female housed with other females, and female housed with at least one male. Active corpora lutea were identified in 66% (10/15) of females housed alone, 85% (6/7) of females housed with other females, and 58% of females housed with a male. A chi-squared test found the presence of active corpora lutea was independent of social housing condition. These results offer strong evidence of spontaneous ovulation in tigers. This finding suggests that a luteal control protocol with an early follicular inhibition agent may improve assisted reproduction efforts and supports spaying nonreproductive or postreproductive female tigers to reduce the rate of uterine infections.

Tigers against the odds: Applying macro-ecology to species recovery in India

Tigers are in serious decline from anthropogenic pressures: prey depletion by human hunting, killing of tigers for conflict mitigation or trade in their body parts, and habitat loss or degradation. In spite of conservation efforts over 50 years, wild tigers now occupy <7% of their historic range. Reproducing tiger populations survive in <1% of the ~1.6 million km2 potential habitat. Evaluating both successful and failed conservation efforts is critical to reversing tiger declines. Wild tiger populations are managed by governments under constraints imposed by other stake-holders. We review recoveries of tigers across a ~38,000 km2 area landscape matrix in Malenad region in southwestern India, during the past five decades. We examine data and empirical observations on tiger ecology, human impacts, emergent conflicts, as well as conservation interventions made at macro-ecological scales by the non-governmental project titled Malenad Tiger Program. We estimate that between 1970 and 2015, tiger habitat occupancy remained unchanged at 14,000 km2, out of ~21,000 km2 of potential habitat in Malenad. However, tiger numbers rose from ~70 to ~391, only because of sporadic recoveries in a few wildlife reserves. We conclude that if tiger recovery efforts can be optimized in future, the Malenad landscape can potentially support ~1300 wild tigers. We propose pragmatic strategies that may improve success rates and cost-effectiveness of future recovery efforts directed at tigers, and, generally at other threatened large carnivores. We evaluate both challenges and opportunities that non-governmental conservation programs must address to be effective in assisting tiger recoveries in the future.

Demographic and ecological correlates of a recovering tiger (Panthera tigris) population: Lessons learnt from 13-years of monitoring

Efforts are on to recover tiger populations range-wide, but we lack suitable metrics to characterise and evaluate such recoveries. Identifying such metrics requires an understanding of tiger population dynamics and its ecological correlates in either recovering populations or those exposed to anthropogenic influences. We monitored a recovering tiger population from 2004 to 2017 in Rajaji National Park, India. Using photographic data and spatial capture-recapture models in an inviolate site vacated by pastoralists (zone 1), we identified demographic parameters of a recovering population. By contrasting it with a site that is presently occupied by pastoralists (zone 3) and one that is isolated (zone 3), we identified conditions facilitating recovery. In zone 1, connected to a large source population in Corbett Tiger Reserve, density increased from 2.08 tigers/100 km2 to 7.07 tigers/100 km2 corresponding to an annual growth rate of 4.5%. Density also increased in zone 2 (2.6 tigers/100 km2 to 6.22 tigers/100 km2), but estimated apparent survival was 0.47 against 0.81 in zone 1. Recovery in zone 1 was accompanied by increased survival of females, while female tenure was shorter in zone 2. Due to the lack of functional connectivity, tigers in zone 3 are facing local extinction. Our results demonstrate that creating inviolate spaces to secure breeding populations and maintaining landscape-wide connectivity to expand breeding cores is critical for recovery. We highlight that relying solely on population increase may lead to unreliable inferences about population performance and instead suggest tracking survival and female land tenure to qualify recovery and success of conservation interventions.

Breaking the Barriers: Displacement to Self- Realization in Bharati Mukherjee’s The Tiger’s Daughter

Breaking the Barriers: Displacement to Self- Realization in Bharati Mukherjee’s The Tiger’s Daughter

How Important Are Resistance, Dispersal Ability, Population Density and Mortality in Temporally Dynamic Simulations of Population Connectivity? A Case Study of Tigers in Southeast Asia

Development of landscape connectivity and spatial population models is challenging, given the uncertainty of parameters and the sensitivity of models to factors and their interactions over time. Using spatially and temporally explicit simulations, we evaluate the sensitivity of population distribution, abundance and connectivity of tigers in Southeast Asia to variations of resistance surface, dispersal ability, population density and mortality. Utilizing a temporally dynamic cumulative resistant kernel approach, we tested (1) effects and interactions of parameters on predicted population size, distribution and connectivity, and (2) displacement and divergence in scenarios across timesteps. We evaluated the effect of varying levels of factors on simulated population, cumulative resistance kernel extent, and kernel sum across nine timesteps, producing 24,300 simulations. We demonstrate that predicted population, range shifts, and landscape connectivity are highly sensitive to parameter values with significant interactions and relative strength of effects varying by timestep. Dispersal ability, mortality risk and their interaction dominated predictions. Further, population density had intermediate effects, landscape resistance had relatively low impacts, and mitigation of linear barriers (highways) via lowered resistance had little relative effect. Results are relevant to regional, long-term tiger population management, providing insight into potential population growth and range expansion across a landscape of global conservation priority.

Philopatric and natal dispersal of tigers in a semi-arid habitat, western India

The connectivity between landscapes is an important aspect of the conservation of small and isolated populations of carnivores. We studied the natal dispersal pattern of Bengal tigers (Panthera tigris tigris) using motion-sensitive cameras and intensive searches from April 2005 to June 2011 in Ranthambhore Tiger Reserve (RTR), western India. We tracked 29 tiger cubs (18 males, 11 females) born during the study until they established independent territories. All the females and 72.2% of the males attained maturity. The males had a greater probability (92.3%) of dispersal compared with the females (36.4%). Males dispersed an average distance of 27.0 ± 12.7 (SE) km (range = 4.5–148 km), while females dispersed an average distance of 5.7 ± 3.03 km (range = 4.6–25.8 km) from their natal area to establish their independent territories. The average age of dispersal was 38.6 ± 2.6 months (range = 24–44 months) for the males and 27.7 ± 2.7 months (range = 25–33 months) for the females. Seven of the 11 females bred at >48 months’ age, after establishing independent territories. Of the other females, three were translocated to another protected area, and one died after the dispersal. This study adds to the baseline information about the dispersal patterns of tigers, which is important in making conservation and management decisions for restoration of tiger populations.