East Rennell is part of Rennell Island, the southernmost island of the Western Pacific, Solomon Islands Group. Rennell Island is the largest raised coral atoll in the world, covering an area of 87,500ha at 86km long and 15km wide and is located 250km due south of the Solomon’s capital, Honiara. The World Heritage property occupies the southern third of the island and includes approximately 37,000ha and a marine area that extends 3km offshore. A prominent feature of the property is Lake Tegano, the former lagoon of the atoll, which at 15,000ha is the largest lake in the insular Pacific. Containing many rugged limestone islets the lake’s brackish waters harbour numerous endemic species including an endemic sea snake. The surrounding karst terrain has a dense cover of indigenous forest. Remaining in its natural state, the forest has a rich biodiversity with many endemic species; four species and nine subspecies of land and water birds respectively, one bat and seven land snails.

The property was the first natural property inscribed on the World Heritage List with customary ownership and management. Approximately 1,200 people of Polynesian origin occupy four villages within the boundaries of the property, living mainly by subsistence gardening, hunting and fishing. Frequent cyclones can have severe consequences for the local people and the biota, and rising lake water levels from climatic change are adversely affecting some staple food crops.

East Rennell demonstrates significant on-going ecological and biological processes and is an important site for the science of island biogeography. The property is an important stepping stone in the migration and evolution of species in the western Pacific and for speciation processes, especially with respect to avifauna. Combined with the strong climatic effects of frequent cyclones, the property is a true natural laboratory for scientific study. The unmodified forest vegetation contains floral elements from the more impoverished Pacific Islands to the east and the much richer Melanesian flora to the west. For its size, Rennell Island has a high number of endemic species, particularly among its avifauna and also harbours 10 endemic plant species.

The wildlife includes 11 species of bat (one endemic) and 43 species of breeding land and water birds (four species and nine subspecies endemic respectively). The invertebrate life is also rich with 27 species of land snail (seven endemics) and approximately 730 insect species, many of which are endemic. The flora of Lake Tegano is dominated by more than 300 species of diatoms and algae, some of which are endemic. There is also an endemic sea snake in the lake.