India’s efforts at tiger conservation received a major boost with the latest census report showing a heartening increase in numbers. The Status of Tigers in India-2018 report by the National Tiger Conservation Authority (NTCA) and Wildlife Institute of India, Dehradun, released on Monday showed that the adult tiger population in India currently stands at 2,967. This represents a 33% increase over the 2014 figures which stood at 2,226. Tiger occupancy has increased in the state of Madhya Pradesh, which ranks highest in tiger population along with Karnataka. India is now estimated to be home to around 70% of the world’s tigers.
The fourth cycle of National tiger status assessment of 2018-19 covered 381,400 km of forested habitats in 20 states of India. A foot survey of 522,996 km was done for carnivore signs and prey abundance estimation. In these forests, 317,958 habitat plots were sampled for vegetation, human impacts and prey dung. Camera traps were deployed at 26,838 locations. These cameras resulted in 34,858,623 photographs of which 76,651 were of tigers and 51,777 were of leopards. The total effective area sampled by camera traps was about 121,337. The total effort invested in the survey was over 620,795 man-days. We believe that this is the world’s largest effort invested in any wildlife survey till date, on all of the above counts.
The Heads of the Governments of Tiger Range countries at St. Petersburg, Russia, had resolved to double tiger numbers across their global range by 2022 by signing the St. Petersburg declaration on tiger conservation. During the said meeting it was also decided to celebrate July 29 as Global Tiger Day across the world, which is since, being celebrated to spread and generate awareness on tiger conservation.
The detailed report assesses the status of tigers in terms of spatial occupancy and density of individual populations across India. The report evaluates the status of habitat corridors connecting major tiger populations and highlights vulnerable areas that require conservation attention for each landscape. The report provides information on major carnivores and ungulates regarding their distribution and relative abundance.
The detailed report of the 4th All India Tiger Estimation is unique in the following ways;
- Abundance index of co-predators and other species has been carried out which hitherto was restricted only to occupancy
- Sex ratio of tigers in all camera trap sites has been carried out for the first time.
- Anthropogenic effects on tiger population have been elaborated in a detailed manner.
- Tiger abundance within pockets in tiger reserves has been demonstrated for the first time.
A total of 2,461 individual tigers (> 1 year of age) were photo-captured. The overall tiger population in India was estimated at 2,967 (SE range 2,603 to 3,346). Out of this, 83% were actually camera trapped individual tigers and 87% were accounted for by camera trap-based capture-mark-recapture and remaining 13% were estimated through SECR covariate based models (Fig. 3.1). Tigers were observed to be increasing at a rate of 6% per annum in India when consistently sampled areas were compared from 2006 to 2018.
Tiger occupancy was found to be stable at 88,9852 km at the country scale since 2014 (88,5582 km). Though there were losses and gains at individual landscapes and state scales. The occupancy reported in this report is based on latest forest cover by Forest Survey of India (2017) and therefore cannot be compared with earlier occupied areas which were computed from earlier forest cover data. To make the comparison on the same scale we have recomputed tiger occupied forests for the 2014 cycle on the forest cover of 2017. Reduction in occupied areas was due to a) not finding evidence of tiger presence in sampled forests (20% actual loss), and b) not sampling forests that had tiger presence in 2014 (8 %). New areas that 2 were colonized by tigers in 2018 constituted 25,709 (28%) km. This analysis suggests that loss and gain of tiger occupancy was mostly from habitat pockets that support low density populations. Such habitats with low density tigers, though contributing minimally to overall tiger numbers, are crucial links for gene flow and maintaining connectivity between source populations. The loss and gain of tiger occupancy in these marginal areas is a dynamic process and depends on several factors like proximity of a tiger source population, anthropogenic pressures operating in the landscape, associated change in habitat conditions and protection regime.
Tiger occupancy has increased in the state of Madhya Pradesh, and Andhra Pradesh. Loss in North East is due to poor sampling. Madhya Pradesh has also registered a substantial increase in their tiger population and along with Karnataka ranks highest in tiger numbers. The poor and continued decline in tiger status in the states of Chhattisgarh, Jharkhand and Odisha is a matter of concern. The largest contiguous tiger population in the world of about 724 tigers was found in the Western Ghats (Nagarhole-Bandipur-Wayanad-Mudumalai-Satyamangalam-BRT block) while the second largest population of about 604 tigers was found across Uttrakhand and western Uttar Pradesh (Rajaji-Corbett-Ramnagar-Pilibhit-Dudhwa block). There were now eight tiger populations in India and trans-boundary Sundarban that numbered over 100 individuals and served as major source populations in the landscapes.
Tiger density was significantly and strongly related with prey abundance indices. Tiger densities increased as chital, sambar and gaur encounter rates as well as their dung density increased. Tiger density was also significantly and strongly related with total tiger prey encounters and dung densities. Amongst habitat indices the amount of forest in a grid, especially forest away from edge effects (core forest area) was significantly and positively related with tiger density. Security in the form of Protected areas harbored higher tiger densities. Human impact indices in the form of night light area, distance to night lights, livestock presence, signs of wood cutting, signs of lopping, human and livestock trails, were negatively and strongly related with tiger density. Encounter rate of tiger sign, (pugmark, scat, rake-marks, and scrape marks) were strongly and significantly related to tiger density.
The magnitude of anthropogenic disturbances within Tiger Reserves and tiger occupied areas were assessed using Relative Abundance Index (RAI) obtained through camera trap images of livestock, free ranging domestic dogs, wild animals with snares, poachers with arms or poached carcasses. Livestock grazing was high in Mukundara, Udanti-Sitanadi, Panna, Buxa, Sariska, Sanjay-Dubri, Achanakmar, Dudhwa and Rajaji Tiger Reserves. While free ranging dogs abounded in Udanti-Sitanadi, Kawal, NSTR, Amrabad, Sariska and Kali Tiger Reserves. RAI for poaching incidences were recorded for Udanti-Sitanadi, Palamau, Srisailam (NSTR), Rajaji, Dampa, Nagarhole, Amdarbad, Dudhwa, Kanha, Pench-MP, and Melghat Tiger Reserves. Snared tiger photos were obtained from Nagarhole TR, Wayanad WLS, Tipeshwar WLS, Terai East Division, Kanha TR, and Dudhwa TR. Snared wildlife was also detected from Pench-MP TR, Rajaji TR, Dampa TR, South Panna Division, Amrabad TR, Udanti-Sitanadi TR, and Melghat TR.
Armed poachers were detected in Palamau TR, Amrabad TR and Udanti Sitanadi TR. Decline and lack of improvement in the status of Udanti-Sitanadi, Achanakmar, Amrabad, Palamu, NSTR and Dampa Tiger Reserves can be correlated with a high disturbance regime and poaching. Incentivized voluntary relocation of tribal communities from the core of NSTR and Amrabad TRs should be a priority. Udanti-Sitanadi was on top of the list of Tiger Reserves for the disturbance indices, and major investments are required in protection especially since the Tiger Reserve has commenced on conservation breeding of the highly endangered swamp buffalo (Bubalus arnee). Feral dogs were detected in most tiger reserves. Dogs are a threat to both ungulates (which they hunt) and to carnivores, since they carry infectious diseases like rabies, parvovirus, and distemper. From amongst tiger reserves that had good spatial camera trap coverage, human impacts were recorded to be low (good protection) for Sundarban, Orang, Kalakad Mundanthurai, Periyar, Corbett, Manas, Kaziranga and Bandipur Tiger Reserves.
(Details and all photographs from “Status of Tigers, copredators and Prey in India” report released by NTCA and WWI. Copyright with respective photographers)
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