Friedhelm Göltenboth

18 – MOUNTAIN FORESTS

Upland forests have an outstanding significance in water management and they hold an important fraction of Indonesian terrestrial biodiversity. The majority of mountains throughout Indonesia are volcanoes. If active, physical changes can be dramatic. Even a layer of only 1 mm ash on a leaf can reduce light penetration by 90%. Nevertheless, Mountain forests play a significant role for maintaining species diversity in Indonesia, since significant tracts of forests, particularly on Sumatra, Java, Bali, Nusatenggara, Sulawesi and the Moluccas are left only in higher altitudes. The forests on these mountain range gives the impression of being stunted in growth with large trees only to be found in sheltered situations. Whether it is the soil conditions, direct climatic effect, or the change of the communities in disperser organisms, the formation of the forest is still unknown. It has been recorded that 81% of the entire mammal population of Borneo is restricted to altitudes below 660 m. It has been recorded that 81% of the entire mammal population of Borneo is restricted to altitudes below 660 m.

16 – TROPICAL LOWLAND EVERGREEN RAINFOREST

About 72% of the land area of the Indonesian archipelago was originally covered with tropical rainforest. However, today only 54% are still in existence officially, but the distribution is not very even. The plants of lowland evergreen forest can be classified as autotrophic plants with chlorophyll (mechanically independent plants), and heterotrophic plants without chlorophyll (saprophytes, parasites). The characterization of Lowland Evergreen Rainforest types is based mainly on the occurrence of economically important species. Since, forests are keystone ecosystems for the maintenance of island ecosystem functions. Hence, direct impacts after forest destruction are discernible from the mountain ranges, to the rivers and other aquatic systems down to the lowlands and near-shore aquatic ecosystems, especially coral reefs and seagrass beds. There is, in fact, no method or technique for exploitation of tropical rainforest which, provides for the retention of all species ad infinitum within the context of cash economy.

11 – ESTUARIES AND SOFT BOTTOM SHORES

This chapter discusses the diversity of benthic habitats peaks in the tropics due to wide variations in monsoonal rainfall. These rainfalls are responsible for the formation and maintenance of many sedimentary systems and habitats, such as fluid mud-banks, carbonate shelves, green and blue anoxic mud regions, mixed terrigenous-carbonate bed forms, stomatolithes, hypersaline lagoons, mangroves and reefs. The majority of terrestrial run-off takes place in the tropics and estuarisation is a specific phenomenon of this fact. Faunal densities in lagoons and estuaries are relatively low and stress factors are relatively high. The epifauna is relatively high and the variations in species richness are wide, reflecting the great range of habitat types and climatic events. Benthic biomass is related to patterns of primary productivity and areas of relatively low biomass are prevalent. Breeding and reproduction is coincided in many cases with the onset of the monsoon. There is evidence of high rates of total community metabolism, bacterial growth and secondary production.

3 – SEAGRASS BEDS

This chapter studies the only marine flowering plants, grown in shallow water. Sea grass are phanaerogames and they comprise two different monocotyl families. Sea grass beds are highly productive marine ecosystems and play a vital role in coastal nutrient dynamics. However, this high productivity can only be utilized directly by a limited set of herbivores, since the living plant matter of the sea grasses is difficult to break down because of its high content in cellulose. Thus, most of the matter and energy flow passes through a detritivore cycle, after free-living microorganisms already broke down at least part of the dead leaves. Indonesian sea-grass beds are not only important nurseries for fish and shrimp, but also are feeding habitat for two spectacular marine vertebrates: the green turtle and the dugong. A specialized epifauna and -flora which utilizes the sea-grasses as substrate also contributes considerably to its biodiversity. Though seagrass beds are no massive structures, they reduce wave and current energy. They seem to be more resistant to storms than coral reefs or mangroves.

4 – CORAL REEFS

This chapter reviews Coral reefs. Out of several reef building organism like red algae, sponges, and molluscs, coral are by far the most important in terms of productivity. They are highly productive ecosystems in an environment which is stable but poor in nutrients. Coral reefs are predominantly formed by hermatypic scleractinian corals and hydrocorals that live in symbiosis with zooxanthellae or dinoflagellate algae. Reef can be divided into four major types: fringing reefs, barrier reefs, atolls reefs, and platform or patch reefs. The outstanding biodiversity in coral reefs is attributed to a fine tuned annidation of the single species that could take place in a quarter of million years. For local fisheries of Indonesia coral reefs belong to the most important fishing grounds, though, they are easily destroyed by nonsustainable methods of exploitation. Presently the most severe impacts on coral reefs in Indonesia are siltation caused by terrestrial runoff due to deforested hinterlands, nonsustainable methods of marine resource exploitation, namely dynamite, cyanide and big vessel fishing.

17 – SPECIAL FOREST ECOSYSTEMS

This chapter focuses on swamp forests, ironwood forest, and heath forest along with their ecology, producers, consumers, and ecological status. Extension swamp forest areas can be found in both, clear freshwater environments and highly acidic peat swamp areas. These areas are poor from a nutritional point of view and interesting defense mechanisms of the plants have developed there based mainly on phenolic compounds. Plant communities over limestone can be found throughout Indonesia as a mosaic of rich and poor growth dependent on the drainage pattern. Sometimes unique flora and fauna lives in these environments adapted to the relatively often occurring water stress situation. Organisms living in area of ultrabasic rocks need to be adapted to the existing mineral-rich environment. Because these areas are often places of mining activities the study of this ecosystem could give valuable information concerning the regaining of industrial sites. Heath forest develops over poorly buffered soils. Ironwood forests are varying in composition, site to site and from island to island

9 – SEA SHORES AND TIDAL FLATS

Seashore is the meeting place of land and sea. The beach is often regarded as an amalgam of tidal zones and surf and swash zone. Shorelines absorb the energy of wave action and hence, prevent erosion in coastal areas. Depending on tidal regime, tidal zones can be sinks or sources of nutrients. Like mangroves, they can hold among the most productive soils in the tropics. Shoreline habitats can range from steep cliffs, over rocky, boulder and gravel shores, sandy beaches, to silty and muddy flats. This chapter explains that shorelines form a marine-terrestrial ecotone. Parameters of some marine abiotic factors are subjected to extreme variations. Only a limited set of species can survive in this environment by adapting to these fluctuations or by avoiding them through mobility. To avoid competition, the single species have adapted to separate niches which can be quite narrow in space and time. Succession is fast and easy to follow, especially the sessile organisms are easily manipulated, making tidal zones a convenient object for ecological studies. Man for their organisms heavily exploits tidal zones since they are easily accessible and not many pieces of equipment are required for gleaning.

14 – GRASSLANDS AND SAVANNAS

Grassland in most cases is a man-made ecosystem. It covers large areas as a result of logging and slash-and-burn agriculture. It is maintained by regularly burning and cattle grazing. In contrast to forests, they contribute only insignificantly to soil preservation, water cycling, and production of regenerative resources and conservation of biodiversity. Regeneration to closed forest is possible passing through a stage of pioneer trees, when degradation of soils is not too severe and sources of seeds are not too far away. Natural regeneration can be enhanced by active reforestation. Tropical grassland is often referred to as savanna, which is defined as a vegetation form that denotes a continuous graminoid stratum, more or less interrupted by trees or shrubs. Edaphic and climatic savannas can be distinguished, according to the factors that cause their existence. Poor nutrient content of the soils and too much or too little water hamper the succession into forest in natural grasslands.

5 – OPEN OCEAN

For an island state like Indonesia, the open sea has a more prominent significance than for other states. All the sea basins in the archipelago of Indonesia belong to the category of marginal seas. Four major sea basins have been identified for the territory of Indonesia: the Banda Bea Basin, where the Indo-Australian, Eurasian, and Pacific plates meet, the Sulu Sea Basin that is located to the north from the Banda Sea Basin, the Celebes Sea Basin, which is a marginal basin with a flat sea floor, and the South China Sea basin. These open seas are high-nutrient ecosystems. Hence, primary productivity in terms of biomass is fairly high. Recycling of nutrients is fast so that relatively high densities of consumers can establish. Food chains in the pelagic usually consist of five links, sometimes even more, whereas most terrestrial food chains have not more than three to four links.

15 – BEACH FORESTS

Beach forests are ecosystems that can be found adjacent to beaches. Some fruits and seeds are adapted to be dispersed by sea currents by evolving sea water resistance fruits. To a certain degree, beach forest trees are able to prevent coastal erosion. The species poor tree community shows adaptations to salt spray and salty groundwater, high temperature and radiation as well as mobile substrates. Next to nothing is known about invertebrate communities in beach forests. They belong to the few terrestrial ecosystems where the two largest groups within the arthropods, the crustaceans and the insects, compete for resources. Crustaceans dominate the marine ecosystems, whereas insects are much richer in species and individuals in most terrestrial ecosystems. Over the period, beach forests have declined drastically, particularly on the more populated islands of the Indonesian archipelago.