BAOBAB TREES

A recent study has unveiled the origins of baobabs, the tall and uniquely shaped deciduous trees prominently found on the island of Madagascar. Often referred to as the “mother of the forest,” various species of baobabs are also native to Africa and Australia.

The study, titled ‘The rise of baobab trees in Madagascar,’ was conducted by UK, China, and Africa researchers. Published in Nature, it delves into the evolution and spread of these iconic trees and the current threats they face.

2. About Baobab Trees

Baobabs are renowned for their impressive heights, with some reaching up to 50 meters, and their exceptionally long lifespans, which can extend up to 2,000 years. A few baobab trees can be found in India, including a notable one near the Golconda Fort in Telangana that is believed to be over 400 years old.

• Baobabs have trunks with large circumferences and thin, spindly branches. They are often called “upside-down” trees because their tops resemble an uprooted plant turned upside down. According to one Arab legend, "The devil plucked up the tree and thrust the branches into the soil, leaving the roots in the air." This nickname and legend are discussed in the book ‘The Baobabs: Pachycauls of Africa, Madagascar and Australia’ by Gerald E. Wickens and Pat Lowe.
• In local cultures, baobab trees are revered for their multiple uses. The fruits and seeds are edible, the seed oil is used for cooking, and the bark fibre is used for clothing.
• Baobabs are keystone species in their ecosystems. Keystone species provide essential resources, such as food or shelter, to a guild of animals that, in return, provide crucial services like pollination or seed dispersal. The absence of keystone species can destabilize entire ecosystems. For example, baobabs play a crucial biological role in conserving ecosystems that include important constituents such as lemurs, sunbirds, and hawk moths.
• Baobabs belong to the genus Adansonia, which comprises eight distinct species: Adansonia digitata found in continental Africa, Adansonia gregorii in Northwestern Australia, and six other species endemic to Madagascar.

3. Key Findings of the Study

The recent study highlighted both the threats faced by baobab trees and their genetic makeup. It was noted that three species of baobab trees in Madagascar are threatened with extinction, as per the IUCN Red List of Threatened Species. The remaining three species are classified under the Least Concern category, indicating they do not currently face significant threats.

Threats to Baobab Trees

The IUCN identifies several threats to baobabs, including residential and commercial development, livestock farming, and ranching, which require clearing land. However, the study emphasized that even species not directly threatened show declining populations, necessitating more rigorous conservation strategies to ensure their long-term survival. A detailed understanding of the genetics of baobabs is crucial for effective conservation efforts.

Genetic Insights and Evolution

Genomic sequencing of baobabs revealed a consensus on the monophyly of the Malagasy lineage from Madagascar. According to the study, DNA evidence suggests that these iconic trees first arose in Madagascar around 21 million years ago. Their seeds were later dispersed by ocean currents to Australia and mainland Africa, where they evolved into distinct species.

Impact of Climate Change and Inbreeding

The study also warned that climate change poses severe threats to species like Adansonia suarezensis from Madagascar, predicting its potential extinction before 2080. Further assessments of Adansonia suarezensis and Adansonia grandidieri indicated high levels of recent inbreeding. Due to their unique ecological roles and low genetic diversity, these species likely have reduced resilience to ecological disturbances and habitat fragmentation

4. Way Forward

By implementing the strategies, we can ensure the continued survival of these magnificent trees, preserving their ecological and cultural value for future generations. The baobab's story is a reminder of the interconnectedness of our planet and the importance of proactive conservation efforts in safeguarding biodiversity.

Source: The Indian Express