The Agasthyamalai region constitutes an extensive and compact tract of forest-clad mountains and plays a very important role as a watershed and repository of biodiversity. The region receives precipitation from both the southwest and northeast monsoons and has a very short dry season of less than 2-3 months duration. Thus, much of the area is covered in tropical moist forest vegetation, with drier forests occurring chiefly in the rain-shadow regions along the eastern foothills.

The Agasthyamalai region constitutes an extensive and compact tract of forest-clad mountains and plays a very important role as a watershed and repository of biodiversity. The region receives precipitation from both the southwest and northeast monsoons and has a very short dry season of less than 2-3 months duration. Thus, much of the area is covered in tropical moist forest vegetation, with drier forests occurring chiefly in the rain-shadow regions along the eastern foothills.

The hilly areas form a critical water catchment for both the eastern and western coasts. Thus, millions of farmers are dependent on the mountains as a source of water for their crops. The region is also the source of water for many rivers including the Tamaraparani.

The Agasthyamalai is also home to the Kanis, an indigenous, forest-dwelling community. The Kanis once practised shifting cultivation, but most of the 16,000-strong population was relocated when the area was designated a protected area in the 1970s. The Kanis retain a great knowledge of the forest and also a love and respect for the area that has not always been recognised. Their knowledge of medicinal plants is connected to the myths of Agasthya, who is thought to have bestowed healing powers to them as a way to prevent them from becoming a martial race. In the 1990s, much attention was focussed on the Kanis when they struck up an innovative deal to share the proceeds of developing the Arogyapacha (Trichopus zeylanicus) plant with a pharmaceutical company. This plant grows wild in the Agasthyamalai hills and is known for its invigorating properties, which reduce fatigue.

Agasthyamalai is one of the few safest homes in Western Ghats for many endemic animals such as Lion -Tailed Macaque, Nilgiri Langur, Brown Palm Civet, Malabar Spiny Dormouse, Nilgiri Marten and Nilgiri Tahr. The eastern side of Agasthyamalai is composed of the Kalakad Mundanthurai Tiger Reserve (KMTR), a 900 sq km. protected area.

In recent times, the peak and its environs have come under threat from pilgrims, tourists, poachers, and from cattle grazing and illegal cutting and collection of trees and plants.