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Evolution of Kaziranga as the Last Great Home of the One-Horned Rhino
Palaeoecological Evidence from Assam Wetlands
Kaziranga National Park (KNP), located in Assam, is a UNESCO World Heritage Site and the world’s most important stronghold of the Indian one-horned rhinoceros (Rhinoceros unicornis). A recent scientific study has traced the long-term ecological evolution of Kaziranga, explaining how and why it emerged as the last major refuge for this megaherbivore.
The study is important from an examination point of view as it links climate change, vegetation dynamics, megafaunal extinction, and conservation biology using scientific evidence.
Background: Biodiversity Loss and Megafaunal Decline
Rapid urbanization, industrialization, deforestation, and natural disasters such as floods, droughts, earthquakes, and landslides are accelerating global biodiversity loss. Late Quaternary megafaunal extinctions remain a major global concern, and nearly 60 percent of large herbivores are currently threatened worldwide. Southeast Asia has the highest concentration of at-risk megaherbivores.
Northeast India forms part of the Indo-Burma biodiversity hotspot and supports several endangered species. Within this region, Kaziranga National Park represents a rare example of long-term megafaunal survival.
Institution and Methodology (Very Important for Exams)
The study was conducted by scientists from the Birbal Sahni Institute of Palaeosciences (BSIP), an autonomous institute under the Department of Science and Technology (DST).
Researchers extracted a sediment core of just over one metre from the Sohola swamp inside Kaziranga National Park. These sediment layers act as a natural archive preserving pollen grains of plants and fungal spores linked to animal dung. This method helped scientists reconstruct palaeovegetation and palaeoherbivory patterns over thousands of years.
This is the first long-term palaeoecological record from Kaziranga linking vegetation history with herbivore activity.
Key Scientific Findings
The study, published in the journal Catena (Elsevier), shows that Kaziranga’s present landscape is very different from its past. Initially, the region had dense forests and deep swamp conditions with limited wildlife activity. Over time, climatic changes led to less dense forests and shallower wetlands, increasing herbivore movement and grazing activity.
The findings confirm that vegetation structure and climate played a decisive role in shaping suitable habitats for megaherbivores such as the one-horned rhinoceros.
Migration and Confinement of the One-Horned Rhino
Fossil evidence indicates that the Indian one-horned rhinoceros was once widely distributed across the Indian subcontinent. However, since the Holocene period, its geographical range has drastically reduced.
The study highlights that northwestern India experienced climatic deterioration during the late Holocene, particularly during the Little Ice Age, along with increasing human activities such as habitat destruction and overhunting. These factors caused regional extinction of megaherbivores in those areas.
In contrast, northeastern India remained climatically stable for the last ~3300 years with relatively lower human pressure. This stability facilitated eastward migration and eventual concentration of rhinoceroses in Kaziranga National Park.
Significance for Conservation and Policy
The research demonstrates how long-term climate change and vegetation shifts influence wildlife survival, migration, and extinction. Such palaeoecological insights provide a scientific basis for modern conservation planning, habitat management, and climate-resilient wildlife policies.
The study underlines that Kaziranga’s success as a megafaunal refuge is the result of long-term ecological stability rather than short-term protection measures alone.
Exam Gist (Quick Revision)
Kaziranga National Park in Assam is a UNESCO World Heritage Site and the last major stronghold of the Indian one-horned rhinoceros. A study by the Birbal Sahni Institute of Palaeosciences under the Department of Science and Technology used pollen and fungal spores from sediment cores of the Sohola swamp to reconstruct palaeovegetation and palaeoherbivory. Published in the journal Catena, the study shows that climatic stability in northeastern India over the last 3300 years allowed rhinoceroses to survive and migrate eastward, while climatic deterioration and human pressure led to their extinction in northwestern India. The research provides crucial long-term ecological evidence to guide future wildlife conservation under climate change.
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