TAG: GS 3: ENVIRONMENT AND ECOLOGY
THE CONTEXT: In a groundbreaking conservation effort, the Simlipal Tiger Reserve (STR) in Odisha, India, is set to undertake a genetic rescue operation aimed at increasing the genetic diversity of its tiger population.
EXPLANATION:
- This initiative, the first of its kind in India, involves the introduction of two new female tigers into the reserve to mitigate the risks of inbreeding.
- It aims to enhance the long-term viability of the tiger population, particularly its unique melanistic or ‘black’ tigers.
The Issue of Inbreeding and Its Consequences
- Simlipal Tiger Reserve, home to a rare population of melanistic tigers, has faced challenges due to genetic isolation.
- Over time, the reserve’s tiger population has become increasingly homozygous, meaning that the tigers carry two identical copies of genetic variants, including those that could be detrimental to their health and survival.
- This situation has arisen from a lack of gene flow due to the population’s isolation and the limited number of breeding individuals.
- Inbreeding depression is a significant concern in such scenarios, as it can lead to a decrease in the population’s overall fitness, manifesting in reduced reproductive success, survival rates, and potentially leading to extinction.
- The tiger population in Simlipal is particularly vulnerable because of the limited number of breeding males and the high incidence of melanistic traits, which are linked to a mutation in the Transmembrane Amino-peptidase Q (Taqpep) gene.
- This mutation, while not harmful on its own, indicates the broader genetic homogeneity of the population, which poses risks for its long-term survival.
The Unique Melanistic Tigers of Simlipal
- Simlipal’s tigers are known for their unique melanistic appearance, characterized by thick, dark stripes that merge, giving them a distinctive ‘black’ appearance.
- These pseudo-melanistic tigers are a result of a genetic mutation that has become prevalent within this isolated population.
- While this trait is not inherently negative, the underlying genetic homogeneity it represents is a cause for concern.
- According to a 2020 study published in the journal PNAS, the high frequency of this rare phenotype in Simlipal’s tigers is a direct consequence of the population’s isolation and reduced genetic diversity.
- The study identified the specific genetic alteration responsible for the pseudomelanistic appearance and underscored the need for genetic rescue to prevent further inbreeding depression.
The Genetic Rescue Plan
- The Odisha forest department, recognizing the urgency of the situation, has proposed a genetic rescue plan that involves introducing two female tigers from other reserves.
- This strategy aims to introduce new genetic material into the Simlipal population, thereby increasing heterozygosity and reducing the risks associated with inbreeding.
- Field director has confirmed that the proposal has received in-principle approval, and a detailed project report is being prepared for submission to the central government.
- The forest department is coordinating with the governments of Madhya Pradesh and Maharashtra, which are likely sources of the new tigers.
- This initiative is particularly significant as it represents the first genetic rescue operation of its kind in India.
- Once the new female tigers are introduced, they will require time to establish their territory and acclimate to their new environment.
- It is anticipated that it may take up to a year for these tigers to settle in, with breeding likely to occur in the subsequent year.
- The success of this initiative will be measured by the integration of these tigers into the existing population and their ability to breed, thereby increasing genetic diversity and enhancing the population’s resilience.
Expert Insights and Future Implications
- A professor at the National Centre for Biological Sciences and a senior co-author of the research on Simlipal’s pseudomelanistic tigers, has endorsed the genetic rescue initiative.
- The importance of selecting genetically diverse source locations for the new tigers to ensure the success of the operation has been emphasized.
- Ongoing research aims to identify these source locations, ensuring that the introduced tigers will contribute positively to the genetic pool of Simlipal’s population.
- The ultimate success of this genetic rescue effort will depend on how well the new tigers adapt to their environment and integrate with the existing population.
- If successful, this initiative could serve as a model for other conservation efforts in India and globally, where small, isolated populations face similar genetic risks.
Similipal Tiger Reserve:
- Similipal, which derives its name from ‘Simul’ (Silk Cotton) tree, is a national park and a Tiger Reserve situated in the northern part of Orissa’s Mayurbhanj district.
- The tiger reserve is spread over 2750 sq km and has some beautiful waterfalls like Joranda and Barehipani.
- The park is surrounded by high plateaus and hills, the highest peak being the twin peaks of Khairiburu and Meghashini (1515m above mean sea level).
- At least twelve rivers cut across the plain area, all of which drain into the Bay of Bengal.
- The prominent among them are Burhabalanga, Palpala Bandan, Salandi, Kahairi and Deo.