Two ecoregions cover portions of the Nilgiris.
The South Western Ghats moist deciduous forests lie between 250 and 1000 metres' elevation.
These forests extend south along the Western Ghats range to the southern tip of India, and are dominated by a diverse assemblage of trees, many of them deciduous during the winter and spring dry season.
These forests are home to the largest herd of Asian elephants in India, who range from the Nilgiris across towards the Eastern Ghats.
The Nilgiris and the Southwestern Ghats are also one of the most important tiger habitats left in India.

The South Western Ghats montane rain forests ecoregion covers the portion of the range above 1000 metres' elevation.
These evergreen rain forests are extremely diverse.
Above 1500 metres' elevation, the evergreen forests begin to give way to stunted forests, locally called sholas, which are interspersed with open grassland The high grasslands are home to the endangered Nilgiri tahr, which resembles a stocky goat with curved horns.
The Nilgiri tahrs are found only in the montane grasslands of the Southwestern Ghats, and number barely 2000 individuals.

Three national parks protect portions of the Nilgiris.
Mudumalai National Park lies in the northern part of the range where Kerala, Karnataka, and Tamil Nadu meet, and covers an area of 321 km².
Mukurthi National Park lies in the southwest of the range, in Kerala, and covers an area of 78.5 km², which includes intact shola-grassland mosaic, a habitat for the Nilgiri tahr.
Silent Valley National Park is just to the south and contiguous with these two parks, and covers an area of 89.52 km².
Outside these parks much of the native forest has been cleared for grazing cattle, or has been encroached upon or replaced by plantations of tea, eucalyptus, cinchona and acacia.
The entire range, together with portions of the Western Ghats to the northwest and southwest, was included in the Nilgiri Biosphere Reserve in 1986, India's first biosphere reserve.
In January 2010, the Nilgiri Declaration set out a wide range environmental and sustainable development goals to be reached by 2015.

The region has also given its name to a number of bird species, including the Nilgiri pipit, Nilgiri woodpigeon and Nilgiri blackbird.
Two ecoregions cover portions of the Nilgiris. The South Western Ghats moist deciduous forests lie between 250 and 1000 metres' elevation. These forests extend south along the Western Ghats range to the southern tip of India, and are dominated by a diverse assemblage of trees, many of them deciduous during the winter and spring dry season. These forests are home to the largest herd of Asian elephants in India, who range from the Nilgiris across towards the Eastern Ghats. The Nilgiris and the Southwestern Ghats are also one of the most important tiger habitats left in India.
The South Western Ghats montane rain forests ecoregion covers the portion of the range above 1000 metres' elevation. These evergreen rain forests are extremely diverse. Above 1500 metres' elevation, the evergreen forests begin to give way to stunted forests, locally called sholas, which are interspersed with open grassland The high grasslands are home to the endangered Nilgiri tahr, which resembles a stocky goat with curved horns. The Nilgiri tahrs are found only in the montane grasslands of the Southwestern Ghats, and number barely 2000 individuals.
Three national parks protect portions of the Nilgiris. Mudumalai National Park lies in the northern part of the range where Kerala, Karnataka, and Tamil Nadu meet, and covers an area of 321 km². Mukurthi National Park lies in the southwest of the range, in Kerala, and covers an area of 78.5 km², which includes intact shola-grassland mosaic, a habitat for the Nilgiri tahr. Silent Valley National Park is just to the south and contiguous with these two parks, and covers an area of 89.52 km². Outside these parks much of the native forest has been cleared for grazing cattle, or has been encroached upon or replaced by plantations of tea, eucalyptus, cinchona and acacia. The entire range, together with portions of the Western Ghats to the northwest and southwest, was included in the Nilgiri Biosphere Reserve in 1986, India's first biosphere reserve. In January 2010, the Nilgiri Declaration set out a wide range environmental and sustainable development goals to be reached by 2015.
The region has also given its name to a number of bird species, including the Nilgiri pipit, Nilgiri woodpigeon and Nilgiri blackbird.
Nilgiris district