Faunal population includes Elephants, monkeys (Nilagiri Langur, Bonnet Macaque, Lion Tailed Macaque), Leopard, Tiger, Jungle cat, Jackals, Wild Dog, Sloth bear, Mangoose, Indian Gaur, Sambar, Barking deer, Mouse Deer, Wild Boar etc
The main forest types found here are 1) West Coast Tropical Evergreen Forests (1A/C4), 2) Southern Tropical Semi-Evergreen Forest (2A/C2), 3) Grass Land s(11A/C1/DS2), 4)Southern Montane Wet Tempearte Forests(11A/C1). The main species are Canarium strictum, Mesua ferrea, Palquium ellipticum, Calophyllum tomentosum, Cullenia excels, Vateria indica, Hopea parviflora, Dysoxylem malabaricum etc. A rare coniferous species, Nageia wallichiana (Nirambali) that occur only in Trivandrum, Kollam, Pathanamthitta and Periyar Tiger Reserve in Idukki District also seen in the top of Irumbuthara, Pambadumpara and Mappatham. One new species of Impatiens was discovered from the evergreen forest of Mankulam Range and is named as Impatiens mankulamensis. Lot of undiscovered flora and fauna is still remaining in this forest.