Sumba Program

Sumba Island is part of the Lesser Sunda Islands which is administratively located in East Nusa Tenggara Province. Geologically, this 1.1 million hectare island consists of limestone rock and a mixture of clay which is less able to hold water. Its geographical position makes the climate in Sumba typical of this region dry with rainfall dependent on the monsoon and trade wind systems. Because it does not have volcanoes, the land on Sumba does not have a source of volcanic fertility which is reflected in the top layer of the soil being relatively thin and easily eroded by erosion.

In the Central Sumba Landscape (BA-SBT), the elevation of the area starts from sea level to 950 meters above sea level and is highest at Wanggameti peak with a height of 1,200 meters above sea level. The BA-SBT mosaic includes coastal ecosystems, savanna grasslands dominated by expanses of hilly plains that look very dry and even barren in the dry season. Rainy days in a year are limited to a volume of less than 1,500 mm/year.

The dry climate found in Sumba and geophysical conditions that do not support water availability are indications of the importance of maintaining river watersheds (DAS) and riparian ecosystems. In BA-SBT there are 17 watersheds that empty into the Sumba Strait and 15 watersheds that empty into the Indian Ocean out of a total of 92 watersheds in Sumba; in other words, BA-SBT, whose area covers 24% of the island’s area, holds 35% of the watershed in Sumba. This shows the proportion and significant role of BA-SBT for water resources management.

Ecosystems that support natural service functions such as forests are very limited, with only around 6% of their area remaining in the 1990s. In fact, the existence of primary and secondary dry forest ecosystems is also a place where the Sumbanese people carry out various activities such as carrying out cultural or traditional rituals, hunting wild animals such as wild boars, a source of wood for house building materials, and a source of types of wood that are sacred to adherents of the traditional Marapu belief. The Manupeu Tanah Daru National Park area, which is located south of BA-SBT, is one of the stretches that has the largest natural forest cover in Sumba and acts as a carbon binder and store of groundwater reserves for 31 surrounding villages.

The people of Sumba are traditionally and still are generally farmer-breeders; practicing farming as well as raising livestock in everyday life. Despite the dry climate, the agroforestry system is developing by planting long-lived crops such as coconut, candlenut and cashew on more sloping beds, while on flatter stretches it is dominated by seasonal crops such as corn, rice and cassava. Swale systems for planting rice on steep slopes are rarely found here, and irrigation systems are not widely used because farmers rely more on rain-fed systems.

Sumba has an important position in terms of global biodiversity. The uniqueness of the ecosystem and types of wild life have placed Sumba Island as one of 23 Endemic Bird Areas in Indonesia. The Sumba hornbill, walik rawamanu and eight other types of birds are not found anywhere on earth except on Sumba. It is recorded that 24 Important Areas for Biodiversity (Key Biodiversity Areas) are on this island.