About Nayachar Island
- There are around 104 islands which are created in the Indian Sunderbans by river silt deposits. These islands are both habited and uninhabited, and are distributed in West Bengal’s South 24 Parganas and North 24 Parganas districts.
- Nayachar, a newly emerged island in the middle estuary of the Hooghly River, remained largely submerged, rising occasionally above the water level.
- Nayachar is surrounded by water on all sides and the nearest landmass — the sinking island of Ghoramara — is about 30 km away.
Survey by ZSI on Nayachar Island
- The Zoological Survey of India (ZSI) started working on the project since 1989, which aimed at understanding soil stabilisation in an emerging island and the succession of living organisms in a new habitat.
- First Survey:
- In 1989, when ZSI first surveyed the island, it found only three invertebrate soil fauna (organisms living under the soil).
- Till 1990, it was completely barren, with hardly any plant or animal species.
- After a couple of years, the number doubled and, by the late Nineties, it recorded 76 invertebrate fauna, both underground and terrestrial.
- Recent report:
- In October 2017, ZSI published its report as ‘Studies on the Succession and Faunal Diversity and Ecosystem Dynamics in Nayachar Island Indian Sundarban Delta’.
- As per the data, the number of animal species increased to 151 on the island, making it a rare case in ecology.
- The publication is unique in nature as it reveals how an emerging landmass can gradually provide habitats for diverse groups of organisms.
Ecology of Nayachar Island
- Nayachar is a mangrove ecosystem and the species succession we have observed here is unique.
- The natural succession of species on the island has been aided by the inundation of water during tides, and the soil brought from other places by fishermen.
- As per ZSI survey, soon after the emergence of protista (single-celled organisms) on the island, scientists could record salt-tolerant micro fauna from the Acarina and Collembola groups living under the soil.
- The island has not only recorded a growth in species of fauna but also increased in size from 17.99 sq. km. to 46.29 sq. km. within 46 years.
- Nayachar has provided that rare opportunity for researchers to study species succession from a very nascent stage.
- Researchers point out that soil formation and subsequent changes including evolution of species followed the classic textbook pattern soil formation.
- First, Microfauna organic material is released by the soil, which in turn releases energy and CO2. Macrofauna reported on the island is found both in the soil and in the emerging habitation cover.
- The stepped process centres around microfauna like collembolans and mites, and leads to increased nitrification and formation of humus.
- Insects and fish are attracted to the food available in the aquatic habitat and soil vegetation. This also leads to an increased number of avian species.
- It is important to monitor its physical and biological changes with a continuous surveillance system, without allowing any major economic activity on the island.
Section : Environment & Ecology