SAVANNA IN NUSA TENGGARA Indonesia's ...

FAUZIATUL FITRIYAH [201626036]

SAVANNA IN NUSA TENGGARA Indonesia’s rainforests are one of earth’s most biologically and culturally rich landscapes. Sadly, Indonesia has one of the highest deforestation rates in the world, with lost 840,000 hectares of forest in 2012 compared to 460,000 hectares in Brazil, despite its forest being a quarter the size of the Amazon rainforest. However, tropical rain forest is not the most threatened ecosystem in Indonesia, tropical dry forest hold this honor. Tropical dry forest or monsoon forests contrast to rain forest in that the diversity of species and growth forms of a rain forest are missing. The main growth form is the phanerophyte. With increasing aridity, species diversity declines and the canopy becomes increasingly open and lower. Eventhough it has not been precisely mapped, mansoon forest concentrated in dry central band in Indoneia between the two blocks of everwet rain forest on Sunda Shelf and Irian Jaya, and dominate Nusa Tenggara and South Maluku, and are part of the region known as Wallacea, which contains a distinctive flora and fauna representing a mix of Asian and Australasian species. The Lesser Sunda Islands or Kepulauan Nusa Tenggara or Kepulauan Sunda Kecil ("Southeastern Islands") are a group of islands in Maritime Southeast Asia, north of Australia. Together with the Greater Sunda Islands to the west they make up the Sunda Islands. The islands are part of a volcanic arc, the Sunda Arc, formed by subduction along the Sunda Trench in the Java Sea.

Fig. 1 Nusa Tenggara map

The main Nusa Tenggara Islands are, from west to east: Bali, Lombok, Sumbawa, Flores, Sumba, Timor, Alor archipelago, Barat Daya Islands, and Tanimbar Islands. These islands have the driest climate in Indonesia. Rainfall is restricted to three months or less. Generally, rains fall from December through February. The weather becomes drier during March and April, May through November are very dry. Annual precipitation ranges from 500 to 3500 mm, varying greatly by year and location, with proximity to geographic features have a strong impact on local rainfall. Heavy and localized storms may discharge large portions of 1


the annual precipitation within a few days or hours. The volumes of these intense rains exceed the infiltration capacity of soil, resulting in heavy surface runoff and soil erosion. Resulted from forest clearance and repeated burning for grazing and agriculture, the forested area of Nusa Tenggara especially, has declined significantly over the last century. As unsatisfactory and difficulties of monsoon forest classification, and so detailed information on successional stages following disturbance monsoon forest in Nusa Tenggara is sparse. Certainly no cites have been recorded where primary mixed monsoon forest has been clearly established. The disturbance can be natural such as fires started by lightening or volcanic eruption, or caused by people such as vegetation cut down or burnt. Clearing monsoon forest is easier and quicker than clearing rain forest, and burning clears much of the vegetation immidiately for shifting land use, for example as agriculture purpose. This phenomena was debated due to resulted in extensive savanna or grassland formation in Nusa Tenggara. Little research has been carried out on the historical causes of savannas in Nusa Tenggara, whether these vegetation formations are natural or secondary. However it originates, the fact that savanna in Nusa Tenggara now exists where monsoon forests grew a century or more ago, is undeniable. Within the driest ares of Nusa Tenggara, savanna is dominated by an open forest canopy and understorey of drought-resistant mixed grasses and herbs. Seasonal drought in savanna, make continual growth impossible. Plants in arid, exposed savanna must protect their renewal buds from desiccation. Most plants are either parennials, whose above-ground parts die back during the dry season (hemicryptophytes and cryptophytes), or annuals (therophytes), completing their life cycle from seed to seed within one wet season. The repeated burning of this habitat also encourages plants that survive even when all aerial parts are killed. The unfavorable growing condition supports plants to have strong survival mechanism againts severe disturbance. They have long tap roots that can reach the deep water table, thick bark to resist annual fires, and trunks that can store water. The grasses have adaptations that discourage animals from grazing on them; some grasses are too sharp or bitter tasting for some animals, but not others, to eat. The side benefit of this is that every species of animal has something to eat. Different species will also eat different parts of the grass. Many grasses grow from the bottom up, so that the growth tissue doesn't get damaged by grazers. Many plants of the savanna also have storage organs like bulbs and corms for making it though the dry season.

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Savannas in Nusa Tenggara can be classified on the basis of dominant tree species into at least eight types: 1. Albizia chinensis savanna; typical, rather common fire-resistant savanna of West Nusa Tenggara. 2. Palm savanna; dominated by Borassus flabellifer or Coryphautan. It is common on drier soils, as these palms are resistant to long, dry periods. Dominant type savanna on Komodo, Roti and Sawu, and large part of Timor island. 3. Eucalyptus alba savanna; occurs on well-drained, lime-poor soils in drier areas. This plant can not grow when the water table is high. Distributed from central Flores eastward through to Wetar. It is the dominant savanna type in Timor. 4. Melaleuca cajuputi savanna; frequently seen from central Flores eastward through Maluku. 5. Acacia savanna; occurs on thick clays over limestone, with several associated shrubs and trees in East Nusa Tenggara savanna. 6. Casuarina junghuhniana savanna; occurs on barren and poor soil, often borders rivers or occurs on mountain plateux that receive more rain. Particularly characteristic of Sumba and Timor. 7. Zizipus mauritiana savanna; characterized by more prone and waterlogging soils, seen throughout East Nusa Tenggara in pockets. 8. Tamarind savanna; a drought- and fire- resistant, occurs on soils more prone to waterlogging, and near to the coast throughout East Nusa Tenggara.

Fig. 2 Zizipus-Tamarindus savanna on Komodo island, Nusa Tenggara, (a) vegetation profile diagram; (b) two grasses grown in the savanna, Heteropon contortus (right) and Themeda triandra (left)

Among all islands and region of Nusa Tenggara, East Nusa Tenggara has the largest savanna up to 3.2 – 3.5 milion ha from 4.7 milion ha of total land, including savanna and belukar. In regards to people live in this region who need attention due to low welfare. Most of the population of Nusa Tenggara lives in rural areas, closed to monsoon forest and 3


savanna, depending on agriculture for their livelihood. Dry-land farming by smallholder farmers is the basis of agriculture in the regions, which also damaging natural ecosystem by clearing the forest and burning the savanna. However, conserving savanna in Nusa Tenggara is not an easy job. These savanna can not be managed without knowing factors affecting their origins and maintaining their present condition. Experimental, palynological, and palaeontological studies are needed to determine the origins of the savannas. Impact of people on the regions also must be put into perspective. And because Nusa Tenggara is a centre for accelerated development and people have rapidly increasing expectations, pressure is increasing to develop the savannas. In many of dry areas of Nusa Tenggara, people are following a virtual subsistence farming system and one response is to encourage agroforestry and to ‘reforest’ these areas. If the savanna occurs aturally because of climatic and edaphic limitations to plant growth, then trying to ‘reforest’ these areas may not be the most sustainable plan.

References http://www.blueplanetbiomes.org/savanna.htm https://www.ran.org/indonesian-rainforests https://www.theguardian.com/environment/2014/jun/29/rate-of-deforestation-in-indonesiaovertakes-brazil-says-study Monk, K.A., Y. de Fretes, and G. Reksodiharjo-Lilley. 1997. Ecology of Nusa Tenggara: Volume V (Ecology of Indonesia Series). Periplus Editions, pp: 269-299. Mulyoutami, E., G. Sabastian, and J.M. Roshetko. 2016. Pengetahuan dan Persepsi Masyarakat Pengelola Padang Savana Sebuah kajian Gender di Sumba Timur, Indonesia. Working paper no. 245. Bogor, Indonesia: World Agroforestry Centre (ICRAF) Southeast Asia Regional Program. http://dx.doi.org/10.5716/WP16161.PDF Roshetko, J.M. dan Mulawarman. 2002. Wanatani di Nusa Tenggara: Ringkasan hasil lokakarya. Dalam: J.M. Roshetko, Mulawarman, W.J. Santoso and I.N. Oka. Wanatani di Nusa Tenggara. Prosiding Lokakarya Wanatani SeNusa Tenggara, 11-14 November 2001. Denpasar, Bali. International Centre for Research in Agroforestry (ICRAF) dan Winrock International. Sabarno, M.Y. 2002. Baluran National Park savanna. Biodiversitas 3 (1): 207-212. Wiriadinata, H., D. Girmansyah, J.M. Hunter, W.S. Hoover, and K. Kartawinata. 2013. Floristic Study of West Sumbawa, Indonesia. Reinwardtia 13 (5): 391− 404.

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