The large variety of habitats within the Park ensures a great diversity of flora and fauna. By its very nature, the Park preserves most of the species within it, but some species are classified as threatened and receive additional monitoring and protection. These species may be large and charismatic like the Otter and Whooper Swan, spectacular like the Peregrine Falcon and Hen Harrier, dainty like the Bog Orchid, or even quite insignificant (to human eyes) like the Lanceolate Spleenwort. But all require assistance in our modern ever-changing world.
Species may be designated as threatened under various different systems, and hence, one species may be categorised under two or three systems, whilst another may only be classified under one system. In reality, all receive monitoring and protection. All threatened species are classified within the Red Data Book, according to their level of threat. In addition, plants are also listed under the Flora Protection Order; birds are also listed under the Birds Directive, and mammals under both the Habitats Directive and the Wildlife Act. So one species can have several threat designations.
Most mammal species are protected under the Wildlife Act, but of particular note are those populations that are important internationally - namely Badger, Otter, Pine Marten, Irish Hare, Hedgehog, and all the bats.
Nine bird species are threatened, four of which are birds of prey. The Hen Harrier is the most threatened species and is actually in danger of extinction. The Irish populations of Peregrine Falcon and Whooper Swan are also of international importance.
Eight of the Park's plants are classified as threatened - three are vulnerable and five are rare.
Some fish species require protection. Arctic Char is listed as Vulnerable in the Irish Red Data Book, but is now believed to be extinct in Co. Wicklow. Salmon and Brown Trout are also listed.