Sholas are patches of stunted evergreen

Evergreen

In botany, an evergreen plant is a plant that has leaves in all seasons. This contrasts with deciduous plants, which completely lose their foliage during the winter or dry season.There are many different kinds of evergreen plants, both trees and shrubs...

 tropical and subtropical moist broadleaf forest found in valleys amid rolling grassland in the higher montane regions of South India

South India

South India is the area encompassing India's states of Andhra Pradesh, Karnataka, Kerala and Tamil Nadu as well as the union territories of Lakshadweep and Pondicherry, occupying 19.31% of India's area...

. These patches of shola forest are found mainly in the valleys and are usually separated from one another by undulating montane grassland. The shola and grassland together form the shola-grassland complex or shola-grassland mosaic. The word 'shola' is probably derived from the Tamil language

Tamil language

Tamil is a Dravidian language spoken predominantly by Tamil people of the Indian subcontinent. It has official status in the Indian state of Tamil Nadu and in the Indian union territory of Pondicherry. Tamil is also an official language of Sri Lanka and Singapore...

 word cÕlai (சோலை) meaning grove

Grove (nature)

A grove is a small group of trees with minimal or no undergrowth, such as a sequoia grove, or a small orchard planted for the cultivation of fruits or nuts...

., or possibly from the Sanskrit 'gulma' for a thicket of trees, which occurs in prakrit as 'golla'. The shola-forest and grassland complex has been described as a climatic climax vegetation

Climax vegetation

Climax vegetation is the vegetation which establishes itself on a given site for given climatic conditions in the absence of anthropic action after a long time ....

 with forest regeneration and expansion restricted by climatic conditions such as frost or soil characteristics while others have suggested that it may have anthropogenic origins in the burning and removal of forests by early herders and shifting agriculturists.

Distribution and origin

Shola forests are found in the higher altitude hill regions of the Nilgiris, Palnis, the Western Ghats

Western Ghats

The Western Ghats, Western Ghauts or the Sahyādri is a mountain range along the western side of India. It runs north to south along the western edge of the Deccan Plateau, and separates the plateau from a narrow coastal plain along the Arabian Sea. The Western Ghats block rainfall to the Deccan...

 and associated ranges in the states of Karnataka

Karnataka

Karnataka , the land of the Kannadigas, is a state in South West India. It was created on 1 November 1956, with the passing of the States Reorganisation Act and this day is annually celebrated as Karnataka Rajyotsava...

, Kerala

Kerala

or Keralam is an Indian state located on the Malabar coast of south-west India. It was created on 1 November 1956 by the States Reorganisation Act by combining various Malayalam speaking regions....

 and Tamil Nadu

Tamil Nadu

Tamil Nadu is one of the 28 states of India. Its capital and largest city is Chennai. Tamil Nadu lies in the southernmost part of the Indian Peninsula and is bordered by the union territory of Pondicherry, and the states of Kerala, Karnataka, and Andhra Pradesh...

. Although generally said to occur above 2000 meters above sea level, shola forests can be found at 1600 meters elevation in many hill ranges (e.g. Biligiriranga Hills).

The origin of the shola forest and grassland complex has been the subject of scientific debate. Some early researchers suggested that the floristic composition represents a stable final state or climax vegetation. This stability being maintained by climatic conditions such as frost which allow the grass to grow but kill off any forest seedlings. Others have suggested that the grassland may have been created and maintained by early pastoralists and point out that fire has a major role in the maintenance of the grassland. There is evidence for both and several features of the forest trees and the grasslands have been considered and debated. Pollen analysis from bogs in the Nilgiris suggest that the complex of grassland and forest existed 35,000 years ago, long before human impact began. Long term studies on the dynamic processes of vegetation change continue.

Fauna

Due to their isolation, altitude and evergreen character, shola forests are home to many threatened and endemic

Endemic (ecology)

Endemism is the ecological state of being unique to a defined geographic location, such as an island, nation or other defined zone, or habitat type; organisms that are indigenous to a place are not endemic to it if they are also found elsewhere. For example, all species of lemur are endemic to the...

 species

Species

In biology, a species is one of the basic units of biological classification and a taxonomic rank. A species is often defined as a group of organisms capable of interbreeding and producing fertile offspring. While in many cases this definition is adequate, more precise or differing measures are...

. Some of the species found here have close relatives only in the distant evergreen forests of Northeast India and Southeast Asia

Southeast Asia

Southeast Asia, South-East Asia, South East Asia or Southeastern Asia is a subregion of Asia, consisting of the countries that are geographically south of China, east of India, west of New Guinea and north of Australia. The region lies on the intersection of geological plates, with heavy seismic...

. Some others are found nowhere else in the world.
The Western Ghats

Western Ghats

The Western Ghats, Western Ghauts or the Sahyādri is a mountain range along the western side of India. It runs north to south along the western edge of the Deccan Plateau, and separates the plateau from a narrow coastal plain along the Arabian Sea. The Western Ghats block rainfall to the Deccan...

 are one of the globally recognized biodiversity hotspot

Biodiversity hotspot

A biodiversity hotspot is a biogeographic region with a significant reservoir of biodiversity that is under threat from humans.The concept of biodiversity hotspots was originated by Norman Myers in two articles in “The Environmentalist” , revised after thorough analysis by Myers and others in...

s. Among the many larger animals inhabiting a shola-grassland mosaic are tiger

Tiger

The tiger is the largest cat species, reaching a total body length of up to and weighing up to . Their most recognizable feature is a pattern of dark vertical stripes on reddish-orange fur with lighter underparts...

s and leopard

Leopard

The leopard , Panthera pardus, is a member of the Felidae family and the smallest of the four "big cats" in the genus Panthera, the other three being the tiger, lion, and jaguar. The leopard was once distributed across eastern and southern Asia and Africa, from Siberia to South Africa, but its...

s, elephant

Asian Elephant

The Asian or Asiatic elephant is the only living species of the genus Elephas and distributed in Southeast Asia from India in the west to Borneo in the east. Three subspecies are recognized — Elephas maximus maximus from Sri Lanka, the Indian elephant or E. m. indicus from mainland Asia, and E. m....

s and gaur

Gaur

The gaur , also called Indian bison, is a large bovine native to South Asia and Southeast Asia. The species is listed as vulnerable on the IUCN Red List since 1986 as the population decline in parts of the species' range is likely to be well over 70% over the last three generations...

. The endangered Nilgiri Tahr

Nilgiri Tahr

The Nilgiri Tahr, Nilgiritragus hylocrius, known locally as the Nilgiri Ibex or simply Ibex, is an ungulate that is endemic to the Nilgiri Hills and the southern portion of the Western Ghats in the states of Tamil Nadu and Kerala in southern India. It is the state animal of Tamil Nadu...

 (an Asian goat-antelope) is endemic to the shola-grassland, and its range is now restricted to a 400-km stretch of shola-grassland mosaic, from the Nilgiri Hills to the Agasthyamalai Hills

Agasthyamalai Hills

The Agasthyamalai Hills also called the Ashambu Hills, lie at the extreme southern end of the Western Ghats mountain range along the western side of South India. There are at least 26 peaks over among these hills...

. Laughingthrush

Laughingthrush

The Laughingthrushes are the genus Garrulax of the large Old World babbler family of passerine birds. They occur in tropical Asia, with the greatest number of species occurring in the Himalaya and southern China....

es, Nilgiri Woodpigeons, Shortwing

Shortwing

The shortwings are colourful medium-sized mostly insectivorous birds in the genus Brachypteryx of the thrush family Turdidae. In addition to these another species, the Great Shortwing, Heinrichia calligyna, is known as a shortwing....

s, and some of the endemic flycatchers (Black-and-Orange and Nilgiri Verditer) are some of the 300+ species of birds that inhabit this area. The area shows high endemicity and is rivalled only by the forests in northeast India; 35 percent of the plants, 42 percent of the fish

Fish

Fish are a paraphyletic group of organisms that consist of all gill-bearing aquatic vertebrate animals that lack limbs with digits. Included in this definition are the living hagfish, lampreys, and cartilaginous and bony fish, as well as various extinct related groups...

es, 48 percent of the reptile

Reptile

Reptiles are members of a class of air-breathing, ectothermic vertebrates which are characterized by laying shelled eggs , and having skin covered in scales and/or scutes. They are tetrapods, either having four limbs or being descended from four-limbed ancestors...

s, and 75 percent of the amphibian

Amphibian

Amphibians , are a class of vertebrate animals including animals such as toads, frogs, caecilians, and salamanders. They are characterized as non-amniote ectothermic tetrapods...

s that live in these rain forests are endemic species.

Flora

At least 25 types of trees are present in the major sholas of the Nilgiri Hills. The dominant trees in this type of forest are Michelia niligarica, Bischofia javanica

Bischofia javanica

Bischofia javanica is a plant species of the family Phyllanthaceae. It and the related B. polycarpa are the only two members of genus and tribe...

 (Bishop wood), Calophyllum tomentosa, Cedrela toona (Indian Mahogany), Eugenia

Eugenia

Eugenia is a genus of flowering plants in the myrtle family Myrtaceae. It has a worldwide, although highly uneven, distribution in tropical and subtropical regions. The bulk of the approximately 1,000 species occur in the New World tropics, especially in the northern Andes, the Caribbean, and the...

 (myrtle) spp., Ficus glomerata (Atti or Cluster Fig Tree or Gular Fig tree) and Mallotus

Mallotus

Mallotus may refer to:* A genus of plants in the family Euphorbiaceae: see Mallotus .* A genus of fish in the family Osmeridae: see Capelin....

 spp.Shola forests have an upper storey of small trees, generally Pygeum gardneri, Schefflera

Schefflera

Schefflera is a genus of flowering plants in the family Araliaceae. The plants are trees, shrubs or lianas, growing tall, with woody stems and palmately compound leaves. The circumscription of the genus has varied greatly...

 racemosa, Linociera ramiflora, Syzygium

Syzygium

Syzygium is a genus of flowering plants that belongs to the myrtle family, Myrtaceae. The genus comprises about 1100 species, and has a native range that extends from Africa and Madagascar through southern Asia east through the Pacific...

 spp., Rhododendron nilgiricum, Mahonia

Mahonia

Mahonia is a genus of about 70 species of evergreen shrubs in the family Berberidaceae, native to eastern Asia, the Himalaya, North America and Central America. They are closely related to the genus Berberis. Botanists disagree on the acceptability of the genus name Mahonia...

 nepalensis, Elaeocarpus

Elaeocarpus

Elaeocarpus is a genus of tropical and subtropical evergreen trees and shrubs. The approximately 350 species are distributed from Madagascar in the west through India, Southeast Asia, Malaysia, southern China, and Japan, through Australia to New Zealand, Fiji, and Hawaii in the east. The islands of...

 recurvatus, Ilex denticulata, Michelia

Michelia

Michelia is a genus of flowering plants belonging to the Magnolia family . The genus includes about 50 species of evergreen trees and shrubs, native to tropical and subtropical south and southeast Asia , including southern China.-Description:The Magnoliaceae are an ancient family; fossil plants...

 nilagirica, Actinodaphne

Actinodaphne

Actinodaphne is an Asian genus of the family Lauraceae, Laurel bay related, that comprises a group of flowering plants within the order Laurales.-Overview:...

 bourdellonii, and Litsea

Litsea

Litsea is a genus of evergreen or deciduous trees or shrubs belonging to the Laurel family, Lauraceae. The genus includes 200 to 400 species in tropical and subtropical areas of both hemispheres.-Overview:Trees or shrubs, dioecious...

 wightiana. Below the upper story is a low understory and a dense shrub layer. There is a thick concentration of mosses growing on the ubderstory and many ferns in the sunlit narrow transition to grassland.

Shola forests are interspersed with montane grasslands, characterized by frost- and fire-resistant grass

Grass

Grasses, or more technically graminoids, are monocotyledonous, usually herbaceous plants with narrow leaves growing from the base. They include the "true grasses", of the Poaceae family, as well as the sedges and the rushes . The true grasses include cereals, bamboo and the grasses of lawns ...

 species like Chrysopogon zeylanicus, Cymbopogon flexuosus, Arundinella ciliata, Arundinella mesophylla, Arundinella tuberculata, Themeda tremula, and Sehima nervosum.

Threats

Invasive Introduced species

Introduced species

An introduced species — or neozoon, alien, exotic, non-indigenous, or non-native species, or simply an introduction, is a species living outside its indigenous or native distributional range, and has arrived in an ecosystem or plant community by human activity, either deliberate or accidental...

 are a serious threat to this high altitude ecosystem. Some, like Acacia mearnsii and Eucalyptus globulus

Eucalyptus globulus

The Tasmanian Blue Gum, Southern Blue Gum or Blue Gum, is an evergreen tree, one of the most widely cultivated trees native to Australia. They typically grow from 30 to 55 m tall. The tallest currently known specimen in Tasmania is 90.7 m tall...

 are the consequence of commercial plantation and afforestation drives. Other threatening invasives include Lantana camara

Lantana camara

Lantana camara, also known as Spanish Flag or West Indian Lantana, is a species of flowering plant in the verbena family, Verbenaceae, that is native to the American tropics. It has been introduced into other parts of the world as an ornamental plant and is considered an invasive species in many...

 and Ageratina adenophora

Ageratina adenophora

Ageratina adenophora is a species of flowering plant in the daisy family known by many common names, including eupatory, sticky snakeroot, crofton weed, and Mexican devil.- Description :...

.

Conservation

Periodic fires have been considered to help maintain the grassland, however excessive burning has led to a shrinkage of forest patches and the growth of invasive species

Invasive species

"Invasive species", or invasive exotics, is a nomenclature term and categorization phrase used for flora and fauna, and for specific restoration-preservation processes in native habitats, with several definitions....

.

The shola biome have a high water retention capacity and exists as the precious source of the water for the high altitude organisms are the origin of many streams and rivers in the Western Ghats.

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