Fauna and flora of Silent Valley

Fauna and flora

Valley areas of the park are in a Tropical and subtropical moist broadleaf forests Ecoregion. Hilly areas above 1,000 m are in a South Western Ghats montane rain forests region. Above 1,500 m, the evergreen forests begin to give way to stunted forests, called sholas, interspersed with open grassland. Both are very important to naturalists, biologists and other researchers because the rich biodiversity here has never been disturbed by human settlements. Several threatened species are endemic here. New plant and animal species are often discovered here.

Fauna

Birds

Birdlife International lists 16 bird species in Silent Valley as threatened or restricted: Nilgiri Wood-pigeon, Malabar Parakeet, Malabar Grey Hornbill, White-bellied Treepie, Grey-headed Bulbul, Broad-tailed Grassbird, Rufous Babbler, Wynaad Laughing Thrush, Nilgiri Laughing Thrush, White-bellied Shortwing, Black-and-rufous Flycatcher, Nilgiri Flycatcher, White-bellied Blue-flycatcher, Crimson-backed Sunbird and Nilgiri pipit.

Rare bird species found here include Ceylon Frogmouth and Great Indian Hornbill. The 2006 winter bird survey discovered Long-legged Buzzard, a new species of raptor at Sispara, the park's highest peak. The survey found 10 endangered species recorded in the IUCN Red List including the Red winged crested cuckoo, Malabar Pied Hornbill, Pale harrier. The area is home to 15 endemic species including the Black-and-orange Flycatcher. It recorded 138 species of birds including 17 species that were newly observed in the Silent Valley area. The most abundant bird was the Black bulbul.

Mammals

Gaur, largest of all wild cattle
There are at least 34 species of mammals at Silent Valley including the threatened Lion-tailed Macaque, Niligiri Langur, Malabar Giant Squirrel, Nilgiri Tahr, Peshwa’s Bat (Myotis peshwa) and Hairy-winged Bat. There are nine species of bats, rats and mice.
Distribution and demography of all diurnal primates were studied in Silent Valley National Park and adjacent areas for a period of three years from 1993 to 1996. Fourteen troops of lion-tailed macaque, eighty-five troops of Nilgiri langur, fifteen troops of bonnet macaque and seven troops of Hanuman langur were observed. Of these, the Nilgiri langur was randomly distributed, whereas the lion-tailed macaque troops were confined to the southern sector of the Park. Bonnet macaques and Hanuman langurs were occasional visitors. The Silent Valley forest remains one of the most undisturbed viable habitats left for the endemic and endangered primates lion-tailed macaque and Nilgiri langur.
The tiger, leopard (panther), leopard cat, jungle cat, fishing cat, Common Palm Civet, Small Indian Civet, Brown Palm Civet, Ruddy Mongoose, Stripe-necked Mongoose, Dhole, clawless otter, sloth bear, small travancore flying squirrel, Indian pangolin (scaly anteater), porcupine, wild boar, sambar, spotted deer, barking deer, mouse deer and gaur also live here.

Insects

There are at least 730 identified species of insects in the park. The maximum number of species belong to the orders Lepidoptera and Coleoptera. Many unclassified species have been collected and there is a need for further studies.[29]
33 species of crickets and grasshoppers have been recorded of which one was new. 39 species of true bugs (six new) and two species of Homoptera (both new) have been recorded. 128 species of beetles including 10 new species have been recorded.[30]
Over 128 species of butterflies and 400 species of moths live here. A 1993 study found butterflies belonging to 9 families. The families Nymphalide and Papilionidae contained the maximum number of species. 13 species were endemic to South India, including 5 species having protected status. 7 species of Butterflies were observed migrating in a mixed swarm of thousands of butterflies towards the Silent Valley National Park. In one instance an observer noted several birds attempting to catch these butterflies. The bird species included the Pied Bushchat Saxicola caprata, Nilgiri Pipit Anthus nilghiriensis, Tickell's Warbler Phylloscopus affinis, Greenish Leaf-Warbler Phylloscopus trochiloides and the Oriental White-eye Zosterops palpebrosa.
At least 500 species of earthworms and leeches have also been identified in the park.

Flora

The flora of the valley include about a 1000 species of flowering plants, 108 species of orchids, 100 ferns and fern allies, 200 liverworts, 75 lichens and about 200 algae. A majority Of these plants are endemic to the Western Ghats.[33]
In addition to facilitating recharge of the aquifer, water retention of the catchment basin and preventing soil erosion, every plant in the park from the smallest one celled algae to the largest tree in the forest has unknown potential for beneficial innovations in biotechnology.

Flowering plants

Angiosperm flora currently identified here include 966 species belonging to 134 families and 599 genera. There are 701 Dicotyledons distributed among 113 families and 420 genera. There are 265 Monocotyledons here distributed among 21 families and 139 genera. Families best represented are the Orchids with 108 species including the rare, endemic and highly endangered orchids Ipsea malabarica, Bulbophyllum silentvalliensis and Eria tiagii, Grasses (56), Legumes (55), Rubiaceae (49) and Asters (45). There are many rare, endemic and economically valuable species, such as cardamom Ellettaria cardamomum, black pepper Piper nigrum, yams Dioscorea spp., beans Phaseolus sp., a pest-resistant strain of rice Oryza Pittambi, and 110 plant species of importance in Ayurvedic medicine.[34] Seven new plant species have been recorded from Silent Valley, including in 1996, Impatiens sivarajanii, a new species of Balsaminaceae.

Trees

Occurrence of lion-tailed macaque is dependent on the flowering of Cullenia exarillata in the forest.
Six distinct tree associations have been described in the valley. Three are restricted to the southern sector: (Cullenia exarillata & Palaquium ellipticum), (Palaquium ellipticum & Mesua ferrea(Indian rose chestnut) and (Mesua ferrea & Calophyllum elatum). The remainder are confined to the central and northern parts of the Park: (Palaquium ellipticum & Poeciloneuron indicum), (Calophyllum elatum & Ochlandra sp.) and (Poeciloneuron indicum & Ochlandra sp.).
A study of natural regeneration of 12 important tree species of Silent Valley tropical rain forests showed good natural regeneration of all 12 species. The species studied were Palaquium ellipticum, Cullenia exarillata, Poeciloneuron indicum, Myristica dactyloides, Elaeocarpus glandulosus, Litsea floribunda, Mesua nagassarium, Cinnamomum malabatrum, Agrostistachys meeboldii, Calophyllum polyanthum, Garcinia morella and Actinodaphne campanulata.
Recent selective felling of three trees per acre, has led to the cutting of 48,000 m³ of timber from about 20 km².
There is a huge hollow Kattualying tree here which can fit 12 people inside.

Genetic resources

Throughout human history about 10% of the genetic stock found in the wild has been bred into palatable and higher yielding cereals, fruits and vegetables. Future food security depends on the preservation of the remaining 90% of the stock through protection of high biodiversity habitats like Silent valley.
The National Bureau of Plant Genetic Resources of ICAR (India), Plant Exploration and Collection Division[42] has identified Silent Valley as high in bio-diversity and an important Gene Pool resource for Recombinant DNA innovations. An important example of use of wild germplasm is gene selection from the wild varieties of rice Oryza nivara (Central India) and Oryza Pittambi found in Silent Valley for the traits of broad spectrum disease resistance in high yielding hybrid rice varieties including IR-36, which are responsible for much of the green revolution throughout Asia.[43]
Also, genetic evaluation of plant growth promoting Rhizobacteria obtained from Silent Valley indicated that strain, IISR 331, could increase the growth of black pepper cuttings by 228% and showed 82.7% inhibition of the common plant wilting disease Phytopthora capsici in laboratory tests (in vitro).