Environment

Tiger conservation in a changing climate

  • Blog Post Date 31 July, 2024
  • Perspectives
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The Sundarbans of India and Bangladesh – the only mangrove tiger habitat – is a top priority for global tiger conservation. Discussing the extreme climate vulnerability of the region, Anamitra Anurag Danda argues that efforts need to go beyond what has been envisaged under the ‘Global Tiger Recovery Program 2.0’ for 2023-2034 – failing which the species may become early victims of climate change-induced habitat loss.

This post is the first in a three-part series on tiger conservation in India. 

Over the past century, the tiger (Panthera tigris) has been extirpated from over 90% of its original range1, and the remaining populations are under severe threat from habitat degradation, fragmentation and poaching (Dinerstein et al. 2007). By 2007, vastly reduced estimates of wild populations in key range countries raised concern in the conservation community that tigers were plummeting toward possible extinction in the wild. In response to the growing crisis, the Global Tiger Initiative (GTI) was launched in 2008 as a global alliance of governments, international organisations, civil society, conservation and scientific communities, and the private sector. With the convening power and presence of the World Bank, the GTI platform was, in 2010, able to bring together government officials, including four heads of state from the 13 tiger range countries (TRCs) and like-minded organisations to agree on a global recovery goal. The high-level meeting resulted in a commitment to double the wild tiger population by 2022, a goal popularised as Tx2. The implementation mechanism, called the Global Tiger Recovery Program (GTRP), is a composite portfolio of tiger actions, both national and transnational. 

The period between 2010 and 2022 was eventful. Of the 13 TRCs, only Malaysia and Nepal had unambiguous goals of doubling tiger numbers by 2022. While tiger numbers increased in Bhutan, China, India, Nepal and Russia, their population became functionally extinct2 in Vietnam, Laos, and Cambodia (see Table 1). Nevertheless, during the period, tiger numbers increased by 40%. This was achieved through political will in countries such as Bangladesh, Bhutan, India, Nepal, China and Russia, as well as organised administrative setup for field implementation, effective policy framework, and mobilising resources for a variety of measures, including habitat protection, anti-poaching efforts, prey augmentation, reducing human pressure, and tiger reintroduction. 

Table 1. Tiger recovery goals of TRCs in GTRP 2010-2022

Tiger Range Country

Goal 2022

2010 Estimate of tiger numbers

2022 Estimate of tiger numbers

Bangladesh

Stable or marginally increased tiger numbers

440

114 (2018)

Bhutan

Stable or marginally increased tiger numbers

74 (67-81 in 1998)

131

Cambodia

Restore and conserve at least one source site within Tiger Conservation Landscape that can hold 50 tigers

10-30

0

China

Realise a significant growth in wild tiger populations and a large-scale expansion of restored habitats, and, as a result of stricter protection in the wild tiger range, much richer biodiversity

40-50

60+

India

Safeguard tiger habitat and source population to foster viable tiger population

1,411 (2006)

3,682

Indonesia

Conserve the Sumatran tiger while fostering harmonious tiger coexistence with development activities on Sumatra Island

325

393 (2018)

Lao PDR

Elevate the existing tiger numbers to the level of viable breeding populations

17

0

Malaysia

Doubling Malayan tiger population from 500 to 1,000 in the wild within the Central Forest Spine landscape

500

150

Myanmar

Undertake monitoring to determine the actual population numbers and conserve the tiger at priority tiger habitats

85

28

Nepal

Double tiger numbers

155

355

Russian Federation

Safeguard a viable population of the Amur tiger consisting of at least 500 animals across the Russian Federation

360 (330-390)

573-600

Thailand

Increase the tiger population at the Western Forest Complex Landscape by 50%

200

148-189

Vietnam

Protect and conserve tiger population, its habitat and prey by preventing the decrease and gradually recover and increase the population by 2022

10

0

Total/Average

 

3,642

5,081(an increase of ~40%)

The situation in Southeast Asia remains challenging due to widespread prey and tiger poaching, inadequate patrolling and wildlife crime monitoring, proximity to wildlife trade hubs, forest loss due to commercial needs, rapid infrastructure development causing habitat fragmentation, low investment in wildlife conservation, and poor monitoring.

Although wild tiger populations are increasing in some range habitats, it continues to remain one of the most threatened large cats, and tiger populations cannot fully recover if their range and habitat continue to decrease. Therefore, the overarching vision of GTRP 2.0 (2023-2034) is for the tiger to remain “WILD” in perpetuity. Accordingly, the goals involve ensuring that:


W
ildlife crime across tiger landscapes is effectively addressed;

Institutions for tiger governance are strengthened across range states;

Landscape scale approaches with stakeholder involvement for tiger conservation are widely adopted; and

Development supporting holistic green growth, social equity, and climate resilience is mainstreamed into tiger conservation. 

Tiger conservation in the Sundarbans

Sundarbans is classified as Priority 1 for global tiger conservation because it represents the only mangrove tiger habitat (Sanderson et al. 2010). For that reason, mainstreaming climate resilience into tiger conservation in the Sundarbans is more urgent than any of the other tiger conservation landscapes, and every centimetre of land counts. 

Climate vulnerability is extreme in the Sundarbans of India and Bangladesh since the average elevation of most of the Sundarbans is less than one metre above sea level (Canonizado and Hossain 1998). The action portfolio on Climate Change Adaptation of the GTRP 2.0 is likely to be woefully inadequate for the Sundarbans. While habitat restoration efforts are essential for reversing the damages and creating suitable conditions for tigers, for the Sundarbans, it entails restoration of environmental flows to keep pace with sea level rise and elevation recovery, and creating conditions for supporting higher density of ungulate (hoofed mammal) species. 

According to a modelling exercise using Intergovernmental Panel on Climate Change RCP6.0 and RCP8.5 scenarios, the future of Bengal tigers in the Sundarbans is bleak (Mukul et al. 2019). Results of the exercise suggest a rapid decline in the Bengal tiger population and suitable habitats in the Sundarbans. By 2070, there is unlikely to be any suitable tiger habitat remaining in Bangladeshi Sundarbans. Prior research on tiger population viability has shown that as the number of breeding individuals goes from 50 to 25, the ability of a population to persist declines in a non-linear manner, given stochastic, demographic, genetic, and environmental events (Kenney et al. 1995, Loucks et al. 2009). 

An earlier modelling exercise (Loucks et al. 2009) had found that a 28 centimetre rise in sea level above the year 2000 baseline in Bangladesh Sundarbans might result in a 96% loss of suitable Bengal tiger habitats. The situation in the Indian Sundarbans is not likely to be any different given that there was an increasing east-west trend of 4-7.8millimetre/year rise in sea level for the Sundarbans during the period 1977 through 1998 (Loucks et al. 2009). Another publication states relative sea-level rise in the Ganges delta to be 8-18millimetre/year (Syvitski et al. 2009). During the period 2000 through 2020, the Indian Sundarbans lost about 11,000 hectares (ha) of mangrove land at the rate of approximately 550 ha/year (Samanta et al. 2021). 

The Ganges delta – of which the Sundarbans is the tide-dominated lower deltaic plain – is not only shrinking but also sinking due to sediment compaction from the removal of water from the delta’s underlying sediments, trapping of sediment in reservoirs upstream, and floodplain engineering in combination with global sea level rise. Over a period of 50 years, sediment reduction due to upstream damming is about 30%. Another factor that reduces delta aggradation is that the number of active distributary channels have been reduced by 37% to support navigation in the larger channels; the channels have also become fixed in their location with levees to better protect populated areas from flooding. If distributary channels are free to migrate across a delta plain or episodically switch their position, widespread sedimentation occurs (Syvitski et al. 2009)

Way forward

For the conservation of tigers, prey and their habitats in the Sundarbans, Transboundary and International Cooperation (an anticipated outcome of GTRP 2.0) has to go way beyond what the GTRP 2.0 Action Portfolio has envisaged, and get into river rejuvenation and enhanced shore protection through nature-based solutions. 

Regionally, adaptation activities need to focus on better coordination between India and Bangladesh to identify rivers and mechanisms that would increase sediment delivery and freshwater flows to the Sundarbans. Until then, if proof-of-concept projects already underway in the region are scaled up, it will help buy time by making use of reworked sediments in the system (also see Imtiaz (2021)). However, if large-scale actions to increase resilience of the Sundarbans are not initiated soon, the tigers of the Sundarbans may join the polar bears as early victims of climate change-induced habitat loss.

Opinions expressed in this post are that of the author, and may not necessarily be those of WWF-India or any other organisation, or of the I4I Editorial Board

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Notes:

  1. The historic tiger range, of places on earth where these big cats were found, spanned over 30 countries, from the shores of the Black Sea to the tips of the Korean Peninsula.
  2. Extinction signifies the permanent loss of an organism from the planet. A species is ‘functionally extinct’ when its population is so low that it will not recover. 

Further Reading 

  • Canonizado, JA and A Hossain (1998), ‘Integrated forest management plan for the Sundarbans reserved forest’, Report, Food and Agriculture Organization.
  • Dinerstein, Eric, et al. (2007), “The Fate of Wild Tigers”, Bioscience, 57(6): 508-514.
  • Imtiaz, A (2021), ‘The unlikely protector against Bangladesh's rising seas’, BBC News, 1 September.
  • Kenney, John S, James LD Smith, Anthony M Starfield, Charles W McDougal (1995), “The Long-Term Effects of Tiger Poaching on Population Viability”, Conservation Biology, 9(5): 1127-1133.
  • Loucks, Colby, Shannon Barber-Meyer, Md. Abdullah Abraham Hossain, Adam Barlow and Ruhul Mohaiman Chowdhury (2009), “Sea level rise and tigers: predicted impacts to Bangladesh’s Sundarbans mangroves”, Climatic Change, 98: 291-298.
  • Mukul, Sharif A, et al. (2019), “Combined effects of climate change and sea-level rise project dramatic habitat loss of the globally endangered Bengal tiger in the Bangladesh Sundarbans”, Science of the Total Environment, 663(1); 830-840.
  • Samanta, Sourav, et al. (2021), “Assessment and Attribution of Mangrove Forest Changes in the Indian Sundarbans from 2000 to 2020”, Remote Sensing, 13(24): 4957.
  • Sanderson, Eric W, et al. (2010), “Setting Priorities for Tiger Conservation: 2005–2015”, Tigers of the World (Second Edition): 143-161.
  • Syvitski, James PM, et al. (2009), “Sinking deltas due to human activities”, Nature Geoscience, 2: 681-686. 
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