Stable forests key to south India's unique biodiversity
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By examining 33 groups of animals and plants, scientists discovered that some species slowly evolved thanks to long-term ecosystem stability, while others were shaped by drastic changes in climate and landscape between 11 and 3 million years ago.
Peninsular India extends from the Aravalli mountains southwards, including the Satpuras and Vindhyas, the Eastern Ghats, the Deccan Plateau and global biodiversity hotspot of Western Ghats.
It harbours highly diverse groups of animal and plant species, many of which do not occur anywhere else in the world.
The study published in Ecology Letters uncovered how species evolved and disappeared across South Asia and the wider Asian region.
By analysing the 33 well-studied groups of animals and plants using mathematical models, the team traced patterns of species formation (speciation) and loss (extinction) across the region.
"Each of the groups comprises closely related endemic species and a common ancestor that existed at some point in time. Through millions of years, their descendants spread across the landscape and diversified into multiple species, many of which exist today," said CCMB scientist Dr Jahnavi Joshi.
The researchers found a high disparity in how species are formed or lost across groups of animals and plants. They found evolutionarily related groups, such as different kinds of lizards, exhibited similar rates of forming and losing species.
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They also found that half of animal and plant groups accumulated diversity gradually over millions of years.
"The stability of the tropical forest ecosystems in Peninsular India has allowed for such steady diversification. As a result, this area has served as a refuge for species from severe climate changes," said Joshi.
Pragyadeep Roy, first author of the study, added: "The stability of this ecosystem is surprising given the turbulent geo-climatic past of the landmass.
Peninsular India was once part of the Gondwanaland supercontinent with land masses such as Africa and Australia. It broke away 100 million years ago, drifted northward, and collided with Asia, forming the Himalayas. Despite drastic geo-climatic shifts from this movement, the biodiversity changed steadily.
This highlights the resilience of its forest habitats."
"Global temperatures have been very dynamic across millions of years, and our analysis suggests earth's temperature strongly influences how species are formed in many groups," explained Roy.
The study found that some groups experienced abrupt changes in the rates of forming new species within the time range of 11 to 3 million years ago. "This period was marked by high aridification and monsoon seasonality in Peninsular India with a major expansion of grasses, leading to shrinkage of evergreen forests to the Western Ghats and mountaintops of the Eastern Ghats. These events inflicted changes in the ranges and habitats of organisms, disrupting their earlier evolutionary trends," the study said.
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Time of India
2 days ago
- Time of India
Stable forests key to south India's unique biodiversity
HYDERABAD: A mix of stable tropical forests and ancient climate changes led to peninsular India's unique biodiversity over millions of years, according to a study by researchers at the CSIR-Centre for Cellular and Molecular Biology in Hyderabad. Tired of too many ads? go ad free now By examining 33 groups of animals and plants, scientists discovered that some species slowly evolved thanks to long-term ecosystem stability, while others were shaped by drastic changes in climate and landscape between 11 and 3 million years ago. Peninsular India extends from the Aravalli mountains southwards, including the Satpuras and Vindhyas, the Eastern Ghats, the Deccan Plateau and global biodiversity hotspot of Western Ghats. It harbours highly diverse groups of animal and plant species, many of which do not occur anywhere else in the world. The study published in Ecology Letters uncovered how species evolved and disappeared across South Asia and the wider Asian region. By analysing the 33 well-studied groups of animals and plants using mathematical models, the team traced patterns of species formation (speciation) and loss (extinction) across the region. "Each of the groups comprises closely related endemic species and a common ancestor that existed at some point in time. Through millions of years, their descendants spread across the landscape and diversified into multiple species, many of which exist today," said CCMB scientist Dr Jahnavi Joshi. The researchers found a high disparity in how species are formed or lost across groups of animals and plants. They found evolutionarily related groups, such as different kinds of lizards, exhibited similar rates of forming and losing species. Tired of too many ads? go ad free now They also found that half of animal and plant groups accumulated diversity gradually over millions of years. "The stability of the tropical forest ecosystems in Peninsular India has allowed for such steady diversification. As a result, this area has served as a refuge for species from severe climate changes," said Joshi. Pragyadeep Roy, first author of the study, added: "The stability of this ecosystem is surprising given the turbulent geo-climatic past of the landmass. Peninsular India was once part of the Gondwanaland supercontinent with land masses such as Africa and Australia. It broke away 100 million years ago, drifted northward, and collided with Asia, forming the Himalayas. Despite drastic geo-climatic shifts from this movement, the biodiversity changed steadily. This highlights the resilience of its forest habitats." "Global temperatures have been very dynamic across millions of years, and our analysis suggests earth's temperature strongly influences how species are formed in many groups," explained Roy. The study found that some groups experienced abrupt changes in the rates of forming new species within the time range of 11 to 3 million years ago. "This period was marked by high aridification and monsoon seasonality in Peninsular India with a major expansion of grasses, leading to shrinkage of evergreen forests to the Western Ghats and mountaintops of the Eastern Ghats. These events inflicted changes in the ranges and habitats of organisms, disrupting their earlier evolutionary trends," the study said.
United News of India
2 days ago
- United News of India
Dr Jitendra Singh launches National BioBank' for personalised healthcare for every Indian
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Time of India
3 days ago
- Time of India
Southeast Asia: ‘Rice was grown 10,000 years ago — it first linked India and Southeast Asia'
Dorian Q. Fuller is Professor of Archaeobotany at University College London. Speaking to Srijana Mitra Das at Times Evoke, he discusses rice's roots: What is the core of your research? I am both an archaeologist and a botanist. Tired of too many ads? go ad free now I collaborate on archaeological excavation projects where we recover preserved plant remains, consisting of the remnants of crops, weeds and wild, gathered foods as well as the wood fuel people used for cooking and fires. From that, we study which crops existed in past cultures and different places and how agriculture, plants and the human diet have changed. Where was the earliest evidence of cultivated rice found? First, I should specify there are two distinct species of rice. There's an African rice, cultivated traditionally in parts of West Africa which has a separate origin, and there's Asian rice, grown in India, China, Japan, etc. Within Asian cultivated rice, there are two subspecies — Indica and Japonica, the former more dominant in South Asia, the latter in East Asia. In terms of the earliest evidence for cultivation, that seems related to the Japonica subspecies or its ancestors in China — this comes from parts of the Yangtze River Basin , the Middle Yangtze, like Hunan province, the lower Yangtze around Zhejiang and tributaries to the north, like the Huaihe river. There's a good case to be made for multiple independent starts of cultivation in China going back 10,000 years. Quite separately, you have an early use of wild rice in parts of northern India, especially in the Ganges River Basin, stretching into the Upper Ganges-Yamuna areas. When that was cultivated and domesticated is much debated — I'd say there is evidence for early cultivation in India 5,000 years ago and possibly even 9,000 years ago. Tired of too many ads? go ad free now Importantly, genetic evidence today shows there was ancient hybridisation between East Asian Japonicas and the ancestors of Indica. Introduced rices from East Asia mixed with local varieties in India and produced something new — Indica rice as known today. That explains our picture from modern genomes and archaeological evidence. I think the hybridisation occurred around 4,000 years ago, with an introduced variety that came to India via trade from East Asia. Did rice cultivation change landscapes? Yes — rice is unique among cereals in that it's a wetland species. It likes a lot of water, in contrast to wheat, barley or millets, all semi-arid dryland species. As rice needs water, its initial cultivation, whether in the Yangtze or Ganges Valley, was in naturally flooded areas. As rice agriculture spread upland and southwards through the Deccan in India, it reached dry areas requiring irrigation. People then created bunded paddy fields that trapped rainwater — they started making artificial wetlands. That was transformative of the landscape. Did this also change social structures? Creating artificial wetlands and irrigation systems demands a lot of labour, alongside irrigated rice is highly productive and feeds many more people. As rice cultivation expanded in India and Southeast Asia , it encouraged population growth and density, early urbanisation and the rise of social hierarchy — the control of land, rice and labour to build irrigation works fed into more hierarchical societies. Did rice also impact animal life? Artificial wetlands are a challenge to plough — the water buffalo became suitable. They are native to India, where their domestication happened in the Harappan world independent of rice. As its cultivation grew, its use increased. Paddy fields also attract wetland small fauna and fish like carp. Some became sources of protein in traditional Southeast Asian systems and a comanagement of various kinds of fish in rice paddies developed. Did rice entail interactions across these ancient societies? Yes. With the establishment of rice-based agricultural systems and early urbanisation in north India and the Ganges plains in the Iron Age around 3,000 years ago, craft specialisation started. Fine ceramics, stonework, beads, metallurgy, etc., began — these got traded over long distances. Our earliest evidence for contact between India and Southeast Asia is from then — you see the arrival of Indian-made ceramics, beads, etc., in Southeast Asia, alongside other Indian crops like mung and toor lentils turning up in sites in southern Thailand. Later, ideas of Buddhism and Hinduism spread in Southeast Asia but the first interaction was about craft and agriculture, supported by rice. What are some of the most fascinating archaeobotanical rice relics you've seen? I've worked on the Tianluoshan site in China, discovered in 2004. It was one of the first places where we could recover the spikelet base of rice, a very small structure that attaches the grain to the plant — it undergoes a key morphological change as a result of domestication, where the plant loses the ability to disperse itself by shattering and now requires planting and harvesting by humans. In this archaeological material, we could see the actual gradual change of the population away from the wild, shattering type towards the domesticated type. In 2006, I also visited the Lahuradeva site managed by the Uttar Pradesh State Department of Archaeology . It shows how people there were consuming rice 6,000 years ago, the debate being over how domesticated or wild that food was. What are the implications of climate change for rice — and vice versa? There are arguments that rice contributes to climate change because its wetland environments produce methane — that's not from rice itself but the methanogenic microorganisms in the wetland waters. Of course, most global warming is from fossil fuel use. But there is research now on ways to grow rice that reduce methane output while ensuring productivity. Meanwhile, climate change is altering rainfall distribution in time and space — that is challenging for ricegrowing because it may increase water shortages and drought. Hence, more drought-tolerant species, like millets, are another direction for research. How different is the rice we eat today, compared to ancient varieties? There are continuities and changes. Interestingly, wild rice populations had red grains — now, that's relatively rare compared to white or brown rice today. Earlier, people selected varieties partly for aesthetics and because it was thought white rice cooks faster and tastes different. People also selected for fragrance, from basmati to jasmine. There is no evidence that any of the wild rices were fragrant, though, so that's a mutation. There's been selection for stickiness in Southeast Asia with glutinous rices, which also didn't exist in wild varieties. So, in its long cultural history, humans have changed rice, from a more standard wild form to very different kinds across diverse cultures.
