Until the early 1970s, East Kalimantan remained one of the most forested Provinces in Indonesia, inclusive of extensive wetlands and seasonal lakes that expanded — and contracted — over thousands of square kilometers. Lowland forests, kerangas (heath) forests on sand terraces, and dry land dipterocarp forests characterized the hinterlands. A crescent-shaped arc of deep wetland/peatland extends southwestwards in the area approximately 0.5 degree north and south of the equator, between 116-117E Longitude. The Mesangat wetland lies in the Kelinjau Hulu and Muara Ancalong Districts at the upper end of an inland basin, formed within an extensive depression between the confluence of the Kelinjau and Kedang Kepala Rivers.
Since the 1990s, with the encouragement of both the National and local governments, Kalimantan, has been an important focus for expansion of oil palm plantations. A substantial number of these areas targeted for plantation development are deep peat swamps and wetlands where palms grow or fruit poorly if at all, and are repeatedly drowned by annual flooding sometimes reaching almost four meters in depth. These wetlands are also known to contain populations of at least half a dozen Rare, Threatened or Endangered (RTE) species, some listed as Critically Endangered by the United Nations’ World Conservation Union (IUCN). Unfortunately, as privately leased lands for forestry, agriculture, mining or a combination of those, these RTE species – many poorly studied — face a high probability of local extinction across the landscape. Currently, however, areas allocated as National Parks and Nature Reserves cannot yet adequately cover the range of species diversity that exists. This fact has been demonstrated within or at the periphery of existing oil palm estates in the Hulu Belayan, Kutai Kartanegara Kabupaten (Regency), at least 15 previously unknown species of fish have been discovered by a team of local scientists, assisted by international taxonomists.
As a result of early studies in the Mesangat habitat, a local conservation foundation, the Yayasan Ulin (Ironwood Foundation), was founded by Mr. Richard Robinow of REA Holdings, and launched in April 2009 in order to provide structure and support for forest and conservation of the wetland habitat, that lies within the mixed use landscapes of Kalimantan, earmarked for development and outside any Totally Protected Area.