Table of Contents
Relevance: UPSC GS Paper III: Environment, Biodiversity, Wildlife Conservation, EIA, Hydropower Projects
For Prelims:
- White-Bellied Heron, Ardea insignis, Critically Endangered, IUCN Red List, Schedule I, Wildlife Protection Act, 1972, Lohit River, Riparian Forest, Eastern Himalaya, Hydropower Project
For Mains:
- Basin-level assessment, riverine biodiversity, ecological flow, environmental governance, species-specific conservation, precautionary principle, critical habitat protection, compensatory afforestation limitations
Why in News?
India’s rarest heron, the white-bellied heron, faces a serious conservation threat due to a proposed hydroelectric project in the Lohit river basin of Arunachal Pradesh. The project may alter the river’s flow, turbidity and riparian habitat, which are essential for the bird’s survival.
The concern is greater because the Environmental Impact Assessment of the project did not include the white-bellied heron, even though the Lohit basin supports a major share of India’s remaining population of this species.
About White-Bellied Heron
The white-bellied heron is one of the world’s rarest and most elusive birds
| Aspect | Details |
| Scientific name | Ardea insignis |
| IUCN Status | Critically Endangered |
| Legal protection in India | Schedule I, Wildlife Protection Act, 1972 |
| Habitat | Fast-flowing Himalayan rivers with mature riparian forests |
| Diet | Mainly fish |
| Major Indian range | Limited pockets of Arunachal Pradesh |
The bird was first scientifically described in 1878 from the Teesta region, but it is no longer found there. This shows how specialised riverine species can disappear when their habitat is disturbed.
IUCN Red List
Basic Information
- Established: 1964
- Prepared by: International Union for Conservation of Nature (IUCN)
- It assesses the global extinction risk of animals, plants and fungi.
- It is known as the “Barometer of Life.”
IUCN Red List Criteria
Species are assessed under five scientific criteria—A to E. A species may qualify for a threatened category by meeting any one criterion.
| Criterion | Basis of Assessment |
| A. Population Reduction | Decline in population over a specified period. |
| B. Geographic Range | Restricted or declining geographical distribution, fragmentation or habitat loss. |
| C. Small Population and Decline | Small number of mature individuals along with continuing decline. |
| D. Very Small or Restricted Population | Extremely small population or highly restricted distribution. |
| E. Quantitative Analysis | Statistical estimation of the probability of extinction. |
Important Thresholds
- A population decline of 90% or more may qualify a species as Critically Endangered, depending on the applicable condition.
- Under Criterion C, an Endangered species may have fewer than 2,500 mature individuals, along with continuing decline.
- Under Criterion D:
- Critically Endangered: fewer than 50 mature individuals
- Endangered: fewer than 250 mature individuals
- Vulnerable: fewer than 1,000 mature individuals
- A probability of extinction of at least 50% within 10 years or three generations may qualify a species as Critically Endangered.
IUCN Red List Categories
| Category | Meaning |
| Extinct — EX | No living individual remains after exhaustive surveys. |
| Extinct in the Wild — EW | Survives only in captivity, cultivation or outside its natural range. |
| Critically Endangered — CR | Faces an extremely high risk of extinction in the wild. |
| Endangered — EN | Faces a very high risk of extinction in the wild. |
| Vulnerable — VU | Faces a high risk of extinction in the wild. |
| Near Threatened — NT | Close to qualifying for a threatened category. |
| Least Concern — LC | Widespread or abundant with low extinction risk. |
| Data Deficient — DD | Available information is insufficient for assessment. |
| Not Evaluated — NE | Has not yet been assessed. |
Why the Lohit Basin is Critical
The white-bellied heron has an extremely small population in India. It is found mainly in three river systems:
- Noa-Dehing River
- Lahm River
- Lohit River
The Lahm River is a tributary of the Lohit River. Together, the Lohit basin supports around 70% of India’s white-bellied herons.
Why this matters
- The species depends on connected river habitats.
- It uses different areas for feeding, nesting and roosting.
- Damage to one part of the basin can affect the entire local population.
Therefore, the Lohit basin should be treated as a critical habitat zone, not merely as a project site.
Ecological Needs of the Species
The white-bellied heron has a very specialised survival pattern.
1. Shallow River Waters for Feeding
It hunts mainly in shallow flowing water. Its diet is fish-based, so changes in fish movement or water clarity directly affect its feeding.
2. Mature Riparian Forests for Nesting
The bird uses tall trees in mature riverine forests for nesting and roosting.
3. Low Human Disturbance
The species avoids even minimal human disturbance. This makes roads, tourism, construction and extraction activities highly risky.
4. Stable River Ecology
It requires natural river flow, suitable water depth and low turbidity for successful foraging.
Threat from the Hydropower Project
The proposed hydropower project in the Lohit basin may affect the species in multiple ways.
1. Alteration of River Flow
A dam can change the natural flow of the river. This may reduce shallow-water feeding zones used by the bird.
2. Increased Turbidity
Changes in water clarity can reduce the bird’s ability to locate fish.
3. Loss of Riparian Forest
The project involves clearing mature riverine forest. This can destroy nesting and roosting sites.
4. Habitat Submergence
Submergence of riverbank areas may remove feeding and breeding habitats.
5. Risk of Local Extinction
Since the population is already very small, even limited habitat loss can push the species towards local extinction.
Gaps in Environmental Impact Assessment
The most serious governance concern is that the white-bellied heron was not included in the project’s Environmental Impact Assessment.
Why this is problematic
- The species is Critically Endangered.
- It is protected under Schedule I of the Wildlife Protection Act.
- The Lohit basin supports a major share of its Indian population.
- Its habitat use goes beyond the exact diversion area.
A narrow project-site approach is inadequate for such a species. The assessment should follow a basin-level ecological approach, covering nesting, roosting and feeding zones across the connected river system.
Larger Ecological Concerns
The Eastern Himalaya is part of a global biodiversity hotspot. It has complex river systems, dense forests, fragile slopes and high species diversity.
1. Limits of Compensatory Afforestation
Compensatory afforestation cannot fully replace mature natural forests. A plantation created elsewhere cannot recreate the same riverine ecological functions of old-growth riparian forests.
2. River Systems as Living Ecosystems
Rivers are not only water channels. They support fish, birds, forests, wetlands and local communities.
3. Cumulative Impact of Projects
A single project may look manageable in isolation, but multiple interventions in a river basin can create cumulative ecological stress.
4. Local Community Concerns
Local communities have raised concerns over land submergence, baseline data and exclusion of important ecological and cultural realities from the assessment.
Other Threats to White-Bellied Heron
Apart from the hydropower project, the bird faces several local pressures:
- sand extraction
- fish poisoning
- pollution
- unregulated tourism
- removal of river boulders
- changes in river courses
- human disturbance near nesting areas
These threats weaken the already fragile survival chances of the species.
Conservation Significance
The white-bellied heron case highlights an important UPSC theme: development must be ecologically informed.
1. Beyond Charismatic Species
Indian conservation often focuses on tigers and elephants. Rare species like the white-bellied heron also need urgent protection.
2. Indicator of River Health
The species reflects the health of fast-flowing Himalayan river ecosystems.
3. Need for Precautionary Principle
When a species is critically endangered and its population is extremely small, decision-making must follow the precautionary principle.
4. Better Environmental Governance
Strong laws exist on paper, but implementation gaps can weaken conservation outcomes.
Way Forward
1. Basin-Level Impact Assessment
The Lohit basin should be assessed as one connected ecological unit, not merely as a project diversion area.
2. Species-Specific Conservation Plan
A dedicated recovery plan is needed for the white-bellied heron, focusing on habitat protection, breeding sites and threat reduction.
3. Protect Riparian Forests
Mature riverine forests should be treated as critical nesting and roosting habitats.
4. Strengthen EIA Process
Environmental assessments must include rare and Schedule I species even if they are not recorded exactly within the project boundary.
5. Regulate Local Threats
Illegal sand extraction, fish poisoning, pollution and tourism disturbance should be strictly controlled.
6. Conservation Breeding
India can explore conservation breeding centres and learn from Bhutan’s captive breeding efforts for the species.
7. Ensure Community Participation
Local communities should be involved in biodiversity monitoring and habitat protection.
Conclusion
The white-bellied heron is a symbol of the fragile river ecosystems of the Eastern Himalaya. The proposed hydropower project in the Lohit basin raises larger questions about EIA quality, compensatory afforestation, basin-level planning and species-sensitive development. For a critically endangered species with a very small population, conservation cannot be an afterthought. India needs a science-based, precautionary and basin-level approach to ensure that development does not lead to silent extinction.
UPSC PYQ
Q. ‘Invasive Species Specialist Group’ (that develops Global Invasive Species Database) belongs to which one of the following organizations? (2023)
A) The International Union for Conservation of Nature
B) The United Nations Environment Programme
C) The United Nations World Commission for Environment and Development
D) The World Wide Fund for Nature
Answer: A
Explanation:
- The Invasive Species Specialist Group (ISSG) is a global network of scientific and policy experts on invasive species, organized under the auspices of the Species Survival Commission (SSC) of the International Union for Conservation of Nature (IUCN). Hence, option (a) is correct.
- It was established in 1994.
- The ISSG manages the Global Invasive Species Database (GISD), which provides information on invasive alien species worldwide. The ISSG also maintains other online resources such as the Aliens-L listserv, the Invasive Species Compendium, the Global Register of Introduced and Invasive Species, and the Environmental Impact Classification for Alien Taxa.
CARE MCQ
Q. Consider the following statements regarding the white-bellied heron:
- It is listed as Critically Endangered on the IUCN Red List.
- It is protected under Schedule I of the Wildlife Protection Act, 1972.
- It depends on fast-flowing rivers and mature riparian forests.
- It is commonly found across all major Indian river systems.
Which of the statements given above are correct?
(a) 1, 2 and 3 only
(b) 1 and 4 only
(c) 2, 3 and 4 only
(d) 1, 2, 3 and 4
Correct Answer: (a) 1, 2 and 3 only
Explanation
Statement 1 is correct: The white-bellied heron is listed as Critically Endangered.
Statement 2 is correct: It receives the highest legal protection under Schedule I of the Wildlife Protection Act, 1972.
Statement 3 is correct: It depends on fast-flowing Himalayan rivers, shallow waters and mature riparian forests.
Statement 4 is incorrect: It is now restricted to limited pockets and is not commonly found across India.
FAQs
1. Why is the white-bellied heron in news?
It faces habitat threats from a proposed hydropower project in the Lohit basin.
2. What is its conservation status?
It is Critically Endangered.
3. What legal protection does it get in India?
It is listed under Schedule I of the Wildlife Protection Act, 1972.
4. Where is it found in India?
Mainly in limited river systems of Arunachal Pradesh.
5. Why is the Lohit basin important?
It supports a major share of India’s remaining population of the species.
6. What habitat does it need?
Fast-flowing rivers, shallow waters and mature riparian forests.
