Western blanket bog and heathland are the predominant vegetation types to be found in the Park. The boglands, situated in the lowlying areas, are normally very wet, while higher up the mountains, a drier community of mountain blanket bog develops. Heather covers the mountain sides, with ling, cross-leaved heath and bell heather all very common. Probably the most common and most abundant plant in the Park is purple moor grass, responsible for the colour of much of the landscape throughout the year. Insectivorous plants form an integral part of the bog community. Sundews and butterworts trap and digest insects with their leaves to gain nutrients, which are in short supply in the bogs. Rare plant species from the colder areas of Europe and the Arctic may be found high up in the mountains, such as roseroot, purple and starry saxifrages, lesser twayblade, and mountain sorrel. Conversely, plants from Spain and Portugal are also found in the Park, notably pale butterwort, St. Dabeoc’s heath, which is a member of the heather family, and St. Patrick’s Cabbage.
The birdlife of the Park is varied. Meadow pipits, skylarks, stonechats, chaffinches, robins and wrens are just some of the common song-birds within the Park. Birds of prey are sometimes seen, usually kestrel and sparrowhawk, with merlin and peregrine falcon making occasional visits. Winter brings an increase in the numbers in the Park of some species native to Ireland such as woodcock, snipe, starling, song thrush and mistle thrush, augmented by visitors from other parts of Ireland and abroad as well as winter migrants from north eastern Europe such as redwing and fieldfare.
Rabbits, foxes, stoats, shrews, and bats are often observed at night. In recent years both pine marten and non-native mink have been seen, the latter is a threat to native wildlife species.
The largest mammal in the Park is the Connemara Pony. Although a domestic animal this pony is very much part of the Connemara countryside. A herd of pure-bred Connemara Ponies was presented to the State by the late President Childers and the current herd in the park are direct descendants of those presented by President Childers.