Tiger Distribution Research Articles

Effects of environmental and anthropogenic drivers on Amur tiger distribution in northeastern China

AbstractWe examined environmental and anthropogenic factors drive range loss in large mammals, using presence data of Amur tigers opportunistically collected between 2000 and 2012, and anthropogenic and environmental variables to model the distribution of the Amur tiger in northeastern China. Our results suggested that population distribution models of different subregions showed different habitat factors determining tiger population distribution patterns. Where farmland cover was over 50 km2 per pixel (196 km2), distance was within 15 km to the railway in Changbaishan and road density (length per pixel) increased in Wandashan, the relative probability of Amur tiger occurrence exhibited monotonic avoidance responses; however, where distance was within 150 km of the Sino‐Russia border, the occurrence probability of Amur tiger was relatively high. We analyzed the avoidance or preference responses of Amur tiger distribution to elevation, snow depth and Viewshed. Furthermore, different subregional models detected a variety of spatial autocorrelation distances due to different population clustering patterns. We found that spatial models significantly improved model fits for non‐spatial models and made more robust habitat suitability predications than that of non‐spatial models. Consequently, these findings provide useful guidance for habitat conservation and management.

Amur tiger (Panthera tigris altaica) energetic requirements: Implications for conserving wild tigers

The Global Tiger Recovery Program has identified increasing prey populations as a crucial component of recovering wild tiger numbers because prey density is a key determinant of tiger density, especially for Amur tigers (Panthera tigris altaica) living at the northern limit of tiger distribution, where both tiger and prey densities are the lowest range wide. To understand potential prey requirements for Amur tigers, we developed a predictive energetics model based on allometric scaling and literature values for the costs of reproduction to estimate energetic requirements. We parameterized the energetics model with empirical activity budgets and movement rates estimated from 5GPS radiocollared tigers between 2009 and 2013. To avoid starvation, adult male tigers must consume a minimum of 5.2kg/day, non-reproducing adult females 3.9kg/day, and an adult female raising 4 cubs to independence needs 200% more energy, or an average of 11.4kg/day over the 651day reproduction period. Given knowledge of Amur tiger diet composition and prey biomass in the Russian Far East, male tigers would consume 24.8prey per year, non-reproducing females 18.2prey per year, and a female raising 4 cubs 53.8prey per year. However, our energetics model underestimated empirical consumption rates, emphasizing that while the relative costs of reproduction are valid, wild tigers are likely consuming more prey than predicted by basal metabolic demands alone. Quantifying the energetic requirements of tigers allows resource managers to estimate nutritional carrying capacity, estimate the impact of tigers on prey, and develop science-based conservation recommendations.

First parturition of tigers in a semi-arid habitat, western India

Long-term data of large felids is important to understand their reproductive biology and behavior for effective conservation planning. We used camera trap data and direct sightings from 2005 to 2013 to estimate the age of the first parturition of Bengal tigers (Panthera tigris) in a semi-arid habitat in India. We monitored 11 females in the Ranthambhore Tiger Reserve (RTR) from when they were 2–6 months old. The mean age at first reproduction (impregnation leading to cubs) was 51.3 ± (SE) 4.5 months. The tiger population in RTR is an important source population and genetic pool in the western most distribution of tiger. Thus, continuous monitoring of tiger populations is important to develop an understanding of reproductive biology.

Tigers, leopards, and dholes in a half-empty forest: Assessing species interactions in a guild of threatened carnivores

Top predators often shape their communities through intraguild predation. Few studies have examined communities in which all three components—top predator, intermediate predators, and prey—occur at low densities; such disturbed systems are commonplace in Asia. We tested predictions from intraguild predation theory at a site where low density tigers (top predator), leopards and dholes (intermediate predators) competed for scarce prey. We employed occupancy modeling using sign surveys and camera trapping to investigate prey selection and spatial co-occurrence. Tiger and leopard occupancy matched the availability of their respective prey species, but leopard avoided pigs—a favored prey of tiger. Leopard and dhole had low rates of co-occurrence with tiger, and their detection probabilities were 47–52% lower in tiger-occupied open habitat (compared to closed), despite suitable prey there. Tiger occupancy was highest in prey-rich zones, whereas dholes were concentrated in a prey-poor zone where tigers were scarce, suggestive of mesopredator release. Activity periods of leopard and dhole (diurnal) were significantly different from tiger (nocturnal). In sum, tiger distribution appeared to be driven solely by prey availability, whereas leopard and dhole seemed to be influenced by prey availability and avoidance of tigers, mediated by habitat structure. Results agree with predictions that under intraguild predation the dominant predator’s distribution matches its resources, whereas intermediate predators trade-off food and safety. Knowledge of habitat-mediated risk effects could inform recovery efforts for low density tigers facing potential exploitation competition from more numerous leopards and dholes.

Assessing habitat suitability for tiger in the fragmented Terai Arc Landscape of India and Nepal

TigerPanthera tigrispopulations have declined dramatically in the Terai Arc Landscape (TAL; India and Nepal), and remaining populations are highly fragmented and endangered. As part of a research program to aid tiger management by identifying critical areas for conservation, we aimed to 1) identify the factors which affect the distribution of tigers in the TAL; 2) explore the role of spatial scale in habitat selection; 3) map potentially suitable habitats; and 4) assess the quality of potential corridors linking suitable habitats. We used an approach based on presence and pseudo‐absence data, combining ecological niche factor analysis and generalized linear models. We used an information‐theoretic approach to compare our data on tiger presence with different hypotheses on tiger habitat selection (i.e. protective habitat, prey species, human disturbance), and spatial scales. All hypotheses yielded models with high prediction accuracy (>79%). The most parsimonious model included variables characterizing habitat suitability of the 2 main prey species. More detailed assessment of potentially suitable areas using an extended source‐sink approach suggested that most of the habitats outside the protected areas were attractive sink‐like habitats (i.e. they suffered high levels of human disturbance in otherwise good habitats). Overall, 24% (ca 18 500 km2) of the study area was predicted as suitable (probability cut‐off p>0.5), approximately 7% of which is under protection. Our models showed that protecting the remaining concentrations of tigers requires focusing management efforts on specific areas outside the currently protected areas. These are characterized by good natural suitability; however, they suffer from a high level of human disturbance. Our models underscore the importance of minimizing human disturbances in these areas to avoid that they act as attractive sinks but act as corridors between existing subpopulations.

Historic distribution and recent loss of tigers in China

Historical records can provide important evidence of changes in distributions of wildlife species. Here we discuss the distribution of the tiger (Panthera tigris Linnaeus, 1758) over the past 2000 years in China based on 2635 historical records. We also compare tiger distributions outlined in these records with ecosystem type maps. Throughout this time period, tigers maintained a broad distribution across 7 biomes (from forests to deserts). However, in recent decades the range has been significantly condensed. Today, only 2 populations remain, neither of which is independently viable. Tigers have completely disappeared from the temperate broadleaf and mixed forests of central China, a region that was traditionally their most important biome in China. The continued presence of wild tigers in China is highly dependent on significant conservation measures.

Sumatran tiger (Panthera tigris sumatrae): A review of conservation status

The majority of wild Sumatran tigers are believed to live in 12 Tiger Conservation Landscapes covering approximately 88,000 km(2) . However, the actual distribution of tigers across Sumatra has never been accurately mapped. Over the past 20 years, conservation efforts focused on the Sumatran tigers have increased, but the population continues to decline as a result of several key threats. To identify the status of the Sumatran tiger distribution across the island, an island-wide questionnaire survey comprised of 35 respondents from various backgrounds was conducted between May and June 2010. The survey found that Sumatran tigers are positively present in 27 habitat patches larger than 250 km(2) and possibly present in another 2. In addition, a review on major published studies on the Sumatran tiger was conducted to identify the current conservation status of the Sumatran tiger. Collectively, these studies have identified several key factors that have contributed to the decline of Sumatran tiger populations, including: forest habitat fragmentation and loss, direct killing of tigers and their prey, and the retaliatory killing of tigers due to conflict with villagers. The present paper provides management authorities and the international community with a recent assessment and a base map of the actual distribution of Sumatran tigers as well as a general overview on the current status and possible future conservation challenges of Sumatran tiger management.

Development of tiger habitat suitability model using geospatial tools—a case study in Achankmar Wildlife Sanctuary (AMWLS), Chhattisgarh India

Geospatial tools supported by ancillary geo-database and extensive fieldwork regarding the distribution of tiger and its prey in Anchankmar Wildlife Sanctuary (AMWLS) were used to build a tiger habitat suitability model. This consists of a quantitative geographical information system (GIS) based approach using field parameters and spatial thematic information. The estimates of tiger sightings, its prey sighting and predicted distribution with the assistance of contextual environmental data including terrain, road network, settlement and drainage surfaces were used to develop the model. Eight variables in the dataset viz., forest cover type, forest cover density, slope, aspect, altitude, and distance from road, settlement and drainage were seen as suitable proxies and were used as independent variables in the analysis. Principal component analysis and binomial multiple logistic regression were used for statistical treatments of collected habitat parameters from field and independent variables respectively. The assessment showed a strong expert agreement between the predicted and observed suitable areas. A combination of the generated information and published literature was also used while building a habitat suitability map for the tiger. The modeling approach has taken the habitat preference parameters of the tiger and potential distribution of prey species into account. For assessing the potential distribution of prey species, independent suitability models were developed and validated with the ground truth. It is envisaged that inclusion of the prey distribution probability strengthens the model when a key species is under question. The results of the analysis indicate that tiger occur throughout the sanctuary. The results have been found to be an important input as baseline information for population modeling and natural resource management in the wildlife sanctuary. The development and application of similar models can help in better management of the protected areas of national interest.

Linking monitoring and intervention for improved management of tigers in the Sundarbans of Bangladesh

Baseline data on distribution and abundance of tigers in the Sundarbans is required to identify problem areas and evaluate management strategies. This paper outlines a khal (creek) bank survey of track set frequency throughout the Bangladesh Sundarbans to aid formulation of a management-driven monitoring program. Three teams of two observers surveyed a total of 1 201 km of waterways throughout the Sundarbans, recording 1 338 tiger track sets. These sets became unrecognizable as tiger sign after a mean 10 days (range 6–14). Proportion of detectable sign recorded was 0.91. Mean (±standard error) sample unit track frequency was 1.12 ± 0.86 track sets/km of khal. The mean coefficient of variance in sample unit track rate, estimated by multiple counts of six sample units, was 0.21 (range 0.06–0.34). Track frequency generally increased from northeast to southwest. Four sample units (6%) had signs of reproduction, with a mean litter size of 1.75 ± 0.5. Monte Carlo simulation suggests a monitoring program of one complete survey every two years will have power of 0.8 ( α = 0.2), to detect track frequency declines of ⩾19% and increases of ⩾17%. We recommend this monitoring scheme be implemented on the Indian side of the Sundarbans to provide a standard assessment of the tiger population and to form the basis for setting management objectives and evaluating transboundary conservation initiatives.

Spatial viability analysis of Amur tiger Panthera tigris altaica in the Russian Far East: the role of protected areas and landscape matrix in population persistence

Summary The Amur or Siberian tiger Panthera tigris altaica forms a relatively small and disjunct population of less than 600 individuals in the Russian Far East. Because tigers in this region require large territories to acquire sufficient prey, current strictly protected areas, comprising 3·4% (10 300 km2) of the region, are unlikely to prevent extirpation of the subspecies in the face of expanding forestry and external demand for tiger parts. We used resource selection function models and spatially explicit population models to analyse the distribution and predict the demographic structure of the population to identify policy options that may enhance population viability. A resource selection function model developed from track distribution data predicted that tigers were most likely to occur in lower altitude valley bottoms with Korean pine forest and low human impacts. The results from the spatially explicit population model suggested that current tiger distribution is highly dependent on de facto refugia with low human impacts but without statutory protection, and that small increases in mortality in these areas will result in range fragmentation. Although an expanded reserve network only marginally increases tiger viability under current conditions, it dramatically enhances distribution under potential future scenarios, preventing regional extirpation despite a more hostile landscape matrix. The portion of tiger range most resistant to extirpation connects a large coastal reserve in the central portion of the region with largely unprotected watersheds to the north. A southern block of habitat is also important but more severely threatened with anthropogenic disturbances. The results suggest that preserving source habitat in these two zones and ensuring linkages are retained between blocks of habitat in the north and south will be critical to the survival of the tiger population. Synthesis and applications. Conservation priorities identified in this analysis differ from those suggested by a conservation paradigm focusing only on sustaining and connecting existing protected areas that has been applied to tiger conservation in more developed landscapes with higher prey densities. An alternative paradigm that assesses population viability in a whole‐landscape context and develops priorities for both protected area expansion and increasing survival rates in the landscape matrix may be more appropriate in areas where tigers and other large carnivores coexist with low‐density human populations. Although landscape connectivity merits increased emphasis in conservation planning, identification of landscape linkages should be tied to broad‐scale recommendations resulting from spatial viability analyses in order to prevent misdirection of resources towards protecting corridors that add little to population persistence.

Crouching tigers, hidden prey: Sumatran tiger and prey populations in a tropical forest landscape

AbstractWe examine the abundance and distribution of Sumatran tigers (Panthera tigris sumatrae) and nine prey species in Bukit Barisan Selatan National Park on Sumatra, Indonesia. Our study is the first to demonstrate that the relative abundance of tigers and their prey, as measured by camera traps, is directly related to independently derived estimates of densities for these species. The tiger population in the park is estimated at 40–43 individuals. Results indicate that illegal hunting of prey and tigers, measured as a function of human density within 10 km of the park, is primarily responsible for observed patterns of abundance, and that habitat loss is an increasingly serious problem. Abundance of tigers, two mouse deer (Tragulus spp.), pigs (Sus scrofa) and Sambar deer (Cervus unicolor) was more than four times higher in areas with low human population density, while densities of red muntjac (Muntiacus muntjac) and pigtail macaques (Macaca nemestrina) were twice as high. Malay tapir (Tapirus indicus) and argus pheasant (Argusianus argus), species infrequently hunted, had higher indices of relative abundance in areas with high human density. Edge effects associated with park boundaries were not a significant factor in abundance of tigers or prey once human density was considered. Tigers in Bukit Barisan Selatan National Park, and probably other protected areas throughout Sumatra, are in imminent danger of extinction unless trends in hunting and deforestation are reversed.

Deforestation Trends in a Tropical Landscape and Implications for Endangered Large Mammals

Abstract: The remarkable large‐mammal fauna of the Indonesian island of Sumatra is one of the most endangered on Earth and is threatened by rampant deforestation. We used remote sensing and biological surveys to study the effects of deforestation on populations of endangered large mammals in a Sumatran landscape. We measured forest loss and created a predictive model of deforestation for Bukit Barisan Selatan National Park and an unprotected buffer area based on satellite images between 1985 and 1999. We used automatic cameras to determine the distribution and relative abundance of tigers ( Panthera tigris sumatrae ), elephants ( Elephas maximus ), rhinoceros ( Dicerorhinus sumatrensis ), and tapirs ( Tapir indicus ). Between 1985 and 1999, forest loss within the park averaged 2% per year. A total of 661 km 2 of forest disappeared inside the park, and 318 km 2 were lost in a 10‐km buffer, eliminating forest outside the park. Lowland forest disappeared faster than hill/montane forest ( by a factor of 6 ) and forests on gentle slopes disappeared faster than forests on steep slopes ( by a factor of 16 ). Most forest conversion resulted from agricultural development, leading to predictions that by 2010 70% of the park will be in agriculture and that by 2036 lowland forest habitat will be eliminated. Camera‐trap data indicated avoidance of forest boundaries by tigers, rhinoceroses ( up to 2 km ), and elephants ( up to 3 km ). Classification of forest into core and peripheral forest based on mammal distribution suggests that, by 2010, core forest area for tigers and rhinoceros will be fragmented and reduced to 20% of remaining forest. Core forest area for elephants will be reduced to 0.5% of remaining forest. Halting forest loss has proven one of the most difficult and complex problems faced by Indonesia's conservation agencies today and will require a mix of enforcement, wise land‐use strategies, increased education, capacity to manage, and new financing mechanisms.

Use of oligonucleotide fingerprinting and faecal DNA in identifying the distribution of the Chinese tiger ( Panthera tigris amoyensis Hilzheimer)

Chinese tiger (Panthera tigris amoyensis Hilzheimer) was once distributed in the Zhejiang Province, China, but there have not been any tiger sightings in this province since 1985. Fortunately, within the boundaries of the Fengyangshan-baishanzu State Natural Reserve, gamekeepers have found ‘tiger footprints’ and ‘tiger faeces’ many times since 1998. However, these tracks may have been left by the leopard or clouded leopard, which leave similar tracks. The presence of the Chinese tiger in Zhejiang Province was demonstrated using DNA fingerprinting and faecal DNA. The study not only revealed a new habitat for Chinese tigers, Zhejiang Province, but also provided an effective scatology method to identify the distribution of tigers and other wild felines.

Habitat destruction and poaching threaten the Sumatran tiger in Kerinci Seblat National Park, Sumatra

The Sumatran tiger, categorized as Critically Endangered on the 2002 IUCN Red List, is threatened by poaching for domestic and international markets, by prey depletion from human hunting and by habitat loss from illegal and commercial logging, oil palm production, pioneer farming, mining operations and forest fires. Kerinci Seblat National Park (KSNP) in west-central Sumatra still has large blocks of forest that support tiger populations. In this paper we present information on photo-trapping and tiger distribution in KSNP and adjoining forest. Tigers were found to be present in all habitat types across KSNP. The poaching pressures on tigers and their prey species were evaluated from confiscations of snare traps by Tiger Protection and Conservation Units (TPCU). Poaching pressures were found to be highest for muntjac, then sambar, tiger, and serow and mouse deer. We determined the effectiveness of TPCU patrol size from the number of arrests, and chainsaw and snare trap confiscations per patrol. The success of forest patrols increased with the number of TPCU staff per patrol. We looked at general law enforcement for KSNP, which appeared to be inadequate. To reduce the threat posed by poaching and illegal logging extra TPCU staff are required for patrols, and extra patrol units are required for the northern and southern sections of the Park. In KSNP it is necessary to monitor habitat loss, establish an unambiguous scheme to mitigate human-tiger conflict, and develop a photo-trapping programme to monitor the tiger population.

Landscape Analysis of Tiger Distribution and Habitat Quality in Nepal

Landscape Analysis of Tiger Distribution and Habitat Quality in Nepal

Landscape Analysis of Tiger Distribution and Habitat Quality in Nepal

Despite more than two decades of conservation efforts, only limited information is available on the metapopulation structure of the tiger (Panthera tigris). We report on the geographic distribution of tigers in Nepal in relation to habitat quality and describe an inventory and monitoring system that can be applied across the entire range of the species. Using information from previous studies, interviews with local people, and digital thematic mapper satellite data, we identified four populations of tigers; three occur primarily within the borders of Nepal, and a fourth is across the border in India. We estimate that there are 153 breeding tigers in these four populations. In the Chitwan population, 77% of breeding tigers live in three protected areas; the rest occupy national forests. Tigers in all four populations survive in isolated forest remnants of what was once a continuous subtropical forest zone lying south of the Himalayas. Within central Nepal the ratio of good‐ to poor‐quality tiger habitat ranged from 16% to 86% across seven forest districts. The four areas with the highest ratio of good‐quality habitat (>54%) supported breeding populations, one area with a marginal ratio of good‐quality habitat (46%) was used only occasionally, and the two areas with the lowest ratio of good‐quality habitat (<26%) were not used by tigers. We suggest that when the ratio of good to poor habitat drops below approximately 50%, tigers no longer breed; when it drops below 30%, tigers no longer occur in an area. Estimates of potential tiger habitat and data on habitat used by tigers demonstrate the need to expand current management beyond parks to encompass the entire land base supporting these fragmented populations so that small tiger populations can be managed as ecosystem or tiger management units rather than as portions of populations within protected areas.Análisis de Paisaje de la Distribución de Tigres y Calidad del Hábitat en NepalA pesar de mas de dos décadas de esfuerzos de conservación, la información sobre la estructura metapoblacional del tigre Panthera tigris es viable únicamente en forma limitada. Reportamos la distribución geográfica de tigres del Nepal en relación a la calidad del hábitat y describimos un inventario y un sistema de monitoreo que puede ser aplicado a lo largo del rango de distribución total de la especie. Usando información de estudios previos, entrevistas con pobladores del lugar y datos de mapeadores digitales temáticos, identificamos cuatro poblaciones de tigres; tres de las cuales ocurren principalmente dentro de los límites de Nepal y una cuarta población se encuentra mas allá de la frontera con India. Estimamos que existen 153 tigres reproductores en estas cuatro poblaciones. En la población de Chitwan, 77% de los tigres reproductores viven en áreas protegidas; el resto ocupa bosques nacionales. Los tigres de las cuatro poblaciones sobreviven en bosques remanentes aislados de lo que alguna vez fué un bosque subtropical continuo del Sur de los Himalayas. Dentro de la región central de Nepal y a lo largo de siete distritos forestales, la proporción de tigres en buena y mala condición varía entre 16% y 86%. Las cuatro áreas con la tasa mas alta de calidad de hábitat (>54%) soporta poblaciones reproductoras; un área con una tasa marginal de buena calidad de hábitat (46%) fueron usadas por los tigres únicamente en ocasiones y las otras dos áreas con la tasa más baja (<26%) no fueron usadas. Sugerimos que los tigres no se reproducen si la tasa entre hábitat bueno y malo es más baja de un 50%; si baja más de un 30%, los tigres no se encuentran en el área. Estimaciones de hábitat potencial para tigres y datos de hábitat usado por tigres demuestran la necesidad de expander el manejo actual más allá de los parques y abarcar la totalidad de las tierras que soportan estas poblaciones fragmentadas, de tal manera que puedan ser manejadas como ecosistema o como unidades de manejo para tigres, y no como porciones de poblaciones dentro de áreas protegidas.

Historical change on distribution and quantity of the South-China Tiger (Panthera tigris amoyensis)

As one of five survived tiger subspecies, the South-China tiger (Panthera tigris amoyensis) specially disperses in China. This paper dedicated distribution and quantity of wild South-China tiger, and also introduced distribution, quantity and pedigree of captive South-China tiger. In the middle of this century, about several thousands South-China tiger distributed in following provinces, such as Hunan, Jiangxi, Guizhou, Fujian, Guangdong, Guangxi, Zhejiang, Hubei, Sichuan, Henan, Shanxi, Shanxi, Gansu. etc. Until now, there are only about 20–30 wild South-China tigers distributing in the provinces of Guangdong, Fujian, Jiangxi, and Hunan, Sichuan, and 50 captive South-China tiger are raised in zoos of China.

Effects of Pleasure-Boat Traffic on Macrophyte Growth in Canals

Land use and land cover change has been the primary cause for the habitat loss and fragmentation in the distribution region of Amur tiger (Panthera tigris altaica). Based on the spatiotemporal changes of land use and land cover in the distribution region, as well as their effects on the population dynamics of Amur tiger, this paper analyzed the development process and its characteristics of the main land use types (agricultural land, forest land, and construction land) in this region, with the land use change history being divided chronically into three distinctive periods, i.e., ancient times (prior to 1860), modern times (1860-1949), and contemporary times (after 1949). The results showed that the sporadic land use in ancient times had no significant effects on the survival of Amur tiger, while the extensive and intensive land use after the 1860s was mainly responsible for the decrease of Amur tiger population and its living space. Since 1949, the Amur tiger distribution region has been divided into two parts, i.e., Northeast China and Russia Far East. The differences in land use pattern, policy, and intensity between these two parts led to different survival status of Amur tiger. The key driving forces for the land use change in Amur tiger distribution region were human population increase, policy change, and increased productivity.