The Reserve can be broadly classified as containing three major ecosystems including lowland mesic, lowland wet, and montane wet.

Lowland mesic ecosystems include a variety of grasslands, shrublands, and forests, generally below 3,000 ft (914 m) elevation, with 50 to 75 in (1270 to 1905 mm) of annual rainfall.

Lowland wet ecosystems are generally found below 3,000 ft (914 m) elevation on the windward sides of the island in areas that receive greater than 75 in (1905 mm) of annual precipitation. The Reserve’s lowland wet ecosystems are dominated by kukui, a tree introduced by the Hawaiians who burned its nut oil for light.

The Reserve’s lowland coastal ecosystems contain steep cliffs characterized by plants found in drier areas. These cliffs are dominated by common coastal plants such as kāwelu (Eragrostis variabilis), ‘āhinahina (Artemisia australis), ‘akoko, nehe, ko‘oko‘olau, ‘ilima (Sida fallax), and akoko (Chamaesyce celastroides).

Montane wet communities are found at elevations between 3,000 and 6,600 ft (914 and 2,012 m) in areas with annual precipitation greater than 75 in (1905 mm). The upper part of Hono O Nā Pali Reserve is an eroded plateau with a series of ridges and valleys covered with ‘ōhi‘a dominated montane wet forest communities.

Montane wet communities also include bogs with low-stature ‘ōhi‘a, and a variety of bog-adapted, low-growing shrubs, herbs and sedges.

Native Plants: 214 total taxa, 118 rare

Native Animals: 32 total taxa, 10 rare