Ecoregions of the world, spanning all land area (terrestrial) of the planet, were first defined and mapped in 2001 [1] and subsequently revised in 2017. [2] Later, freshwater ecoregions [3] and marine ecoregions [4] of the world were identified. Within India, there are 46 terrestrial ecoregions, 14 freshwater ecoregions, and 6 marine ecoregions.
The terrestrial ecoregions of the world include 45 ecoregions that fall entirely or partly within the boundaries of India. These ecoregions fall within two biogeographic realms: Indomalayan and Palearctic. They also fall under ten biomes: Deserts and Xeric Shrublands, Flooded Grasslands and Savannas, Mangroves, Montane Grasslands and Shrublands, Temperate Broadleaf and Mixed Forests, Temperate Conifer Forests, Tropical and Subtropical Coniferous Forests, Tropical and Subtropical Dry Broadleaf Forests, Tropical and Subtropical Grasslands, Savannas and Shrublands, and Tropical and Subtropical Moist Broadleaf Forests. The ecoregion Rock and Ice is not included under any specific biome or biogeographic realm. [2]
Freshwater ecoregions of the world have been defined [3] as "a large area encompassing one or more freshwater systems with a distinct assemblage of natural freshwater communities and species. The freshwater species, dynamics, and environmental conditions within a given ecoregion are more similar to each other than to those of surrounding ecoregions, and together form a conservation unit." The following 14 freshwater ecoregions occur within India.
Marine ecoregions of the world have been described across the worlds oceans and seas. [4] India's seas are in the Western Indo-Pacific marine realm. This includes the following four provinces and six marine ecoregions.
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The following are the ecoregions in India that are included in the Global 200 ecoregions: [5]
An ecoregion is an ecologically and geographically defined area that is smaller than a bioregion, which in turn is smaller than a biogeographic realm. Ecoregions cover relatively large areas of land or water, and contain characteristic, geographically distinct assemblages of natural communities and species. The biodiversity of flora, fauna and ecosystems that characterise an ecoregion tends to be distinct from that of other ecoregions. In theory, biodiversity or conservation ecoregions are relatively large areas of land or water where the probability of encountering different species and communities at any given point remains relatively constant, within an acceptable range of variation . Ecoregions are also known as "ecozones", although that term may also refer to biogeographic realms.
The Nearctic realm is one of the eight biogeographic realms constituting the Earth's land surface.
The Neotropical realm is one of the eight biogeographic realms constituting Earth's land surface. Physically, it includes the tropical terrestrial ecoregions of the Americas and the entire South American temperate zone.
The Global 200 is the list of ecoregions identified by the World Wide Fund for Nature (WWF), the global conservation organization, as priorities for conservation. According to WWF, an ecoregion is defined as a "relatively large unit of land or water containing a characteristic set of natural communities that share a large majority of their species dynamics, and environmental conditions". For example, based on their levels of endemism, Madagascar gets multiple listings, ancient Lake Baikal gets one, and the North American Great Lakes get none.
The North Western Ghats moist deciduous forests is a tropical moist broadleaf forest ecoregion of southwestern India.
The South Western Ghats moist deciduous forests is an ecoregion in the Western Ghats of southern India with tropical and subtropical moist broadleaf forests. This biome covers the Nilgiri Hills between elevation of 250 and 1,000 m in Kerala, Karnataka and Tamil Nadu states.
The Upper Gangetic Plains moist deciduous forests is a tropical and subtropical moist broadleaf forests ecoregion of northern India.
The Eastern Highlands moist deciduous forests, presently known as East Deccan moist deciduous forests, is a tropical and subtropical moist broadleaf forests ecoregion in east-central India. The ecoregion covers an area of 341,100 square kilometers (131,700 sq mi), extending across portions of Andhra Pradesh, Chhattisgarh, Jharkhand, Madhya Pradesh, Maharashtra, Odisha, and Telangana states.
The Himalayan subtropical broadleaf forests is an ecoregion that extends from the middle hills of central Nepal through Darjeeling into Bhutan and also into the Indian States of Uttar Pradesh and Bihar. It represents the east–west-directed band of subtropical broadleaf forest at an altitude of between 500 and 1,000 m along the Outer Himalayan Range, and includes several forest types traversing an east to west moisture gradient.
Indo-Burma is a biodiversity hotspot designated by Conservation International.
The Eastern Himalayan broadleaf forests is a temperate broadleaf forest ecoregion found in the middle elevations of the eastern Himalayas, including parts of Nepal, India, Bhutan, Myanmar and China. These forests have an outstanding richness of wildlife.
The ecology of the Himalayas varies with climate, rainfall, altitude, and soils. The climate ranges from tropical at the base of the mountains to permanent ice and snow at the highest elevations. The amount of yearly rainfall increases from west to east along the southern front of the range. This diversity of climate, altitude, rainfall and soil conditions supports a variety of distinct plant and animal species, such as the Nepal gray langur
Biogeographic classification of India is the division of India according to biogeographic characteristics. Biogeography is the study of the distribution of species (biology), organisms, and ecosystems in geographic space and through geological time. India has a rich heritage of natural diversity. India ranks fourth in Asia and tenth in the world amongst the top 17 mega-diverse countries in the world. India harbours nearly 11% of the world's floral diversity comprising over 17500 documented flowering plants, 6200 endemic species, 7500 medicinal plants and 246 globally threatened species in only 2.4% of world's land area. India is also home to four biodiversity hotspots—Andaman & Nicobar Islands, Eastern Himalaya, Indo-Burma region, and the Western Ghats. Hence the importance of biogeographical study of India's natural heritage.
Pangolakha Wildlife Sanctuary is a wildlife reserve in the Pakyong District of the state of Sikkim in India. It is about 28 kilometres (17 mi) east of Rorathang and about 40 kilometres (25 mi) by road from Rangpo city. The total notified area of the park is around 124 square kilometres (48 sq mi) while inside the wildlife sanctuary there are a few hamlets: Aritar, Dakline Lingtam, Phadamchen, Dzuluk, Gnathang Monastery Kupup. This wildlife sanctuary is linked to the forests of Neora Valley National Park of West Bengal as well as forests of Samtse, Bhutan and Haa district Bhutan. The area that comes under this biosphere has been declared in 1999 as a wildlife sanctuary under biogeographic province category 2C.