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its slow. rapid n by Causes of biodiversity loss in coastal ecosystems Els E. Martens * Department of Zoology, University of Nairobi, Po. Box 30197, Nairobi, Kenya Summary rised also ~vent ay be lities 1yof ) the esto ;and .& , et e :0. u Although far less publicised than loss of biodiversity on land, the loss of marine genetic, species and ecosystem diversity is a global crisis in its own right. The coastal strip (the shallow water, the intertidal area and the immediately adjacent land) is the most vulnerable as well as the most abused marine zone. Coastal ecosystems are not only an important source for essential products for mankind, including foods, medicine, raw materials and recreational facilities, but also provide ecologi cal services that directly benefit the coastal zone. Loss of biodiversity in coastal ecosystems has both direct and indirect causes. The direct mechanisms involved include habitat loss and fragmentation, physical alteration, over-exploitation, pollution, introduction of alien species and global climate change. The root causes that drive these proximate threats lie in the high rate of human population growth, the unsustainable use of natural resources, economic policies that fail to value the environment and its resources, insufficient scientific knowledge, and weak legal and institutional systems. The ever-growing exploitation of the coast and its resources is a reflection of the steady population increase, especially in coastal zones. Habitats are changed or lost by accelerating urbanisation, development of tourist facilities, industrial installa tions and mariculture. Land-based and upstream activities alter sedimentation and freshwater input in downstream estuaries and coastal biotopes. Contaminants from sewage disposal and agricultural runoff are rapidly increasing and areas of eutro phication and chemical pollution are expanding. Careless disposal of plastic wastes not only causes a litter problem but also widespread mortality of marine species. Exploitation ofliving marine resources may damage habitats and alter food webs, while mariculture generates its qwn pollution and may upset ecological balances by the introduction ofalien species. Global atmospheric changes, which may result in altered rainfall patterns and rising sea-level, have become a matter of growing concern. Ie ns 10. * Present address: Kenya Wildlife Service - Netherlands Wetlands Conservation Programme, P.O. Box 82144, Mombasa, Kenya 69 Causes of biodiversity loss in coastal ecosystems Biodiversity in marine ecosystems Although fewer marine than land species have been described, marine ecosystems are far more diverse than terrestrial ones. Of the 33 extant animal phyla, only 11 occur on land while 32 are found in the seas. The coastal and marine biotopes host nearly the entire extant diversity of basic animal body plans, and also contain far greater diversity in body size, from whales to picoplankton, than is found on land. Further, filter feeders create extra levels in aquatic food chains, which tend to be more complex than terrestrial ones (Margulis & Schwartz 1988, WRIIIUCN/UNEP 1992). Marine biological diversity is for most groups considerably higher in tropical regions than in cooler waters. Within the tropics, many taxa reach the highest species diversity in the Indo-West Pacific. Tropical, marine ecosystems also have a high diversity in functions benefitting people (Dugan 1990, Hamilton & Snedaker 1984, Martens 1992, Saenger et al. 1983, Salm & Clark 1984). The coastal strip is the most vulnerable and the most abused marine zone. Several aspects of marine systems complicate the task of conservation. First, coastal waters and their organisms extend beyond and move between national boundaries. Second, coastal ecosystems are at the receiving end of drainage from land, and most wastes eventually concentrate there. Third, reproduction ofmarine organisms can be very variable in space and time. Fourth, some species require more than one habitat during development and are threatened by activities in anyone of them (Dugan 1990, Salm & Clark 1984). Marine conservation has only become an issue of global concern within the last 20 years (WRIIIUCN/UNEP 1992). Although a relationship between human population increase and environmental change has long been recognised, attempts have only recently been made to assess the cumulative impacts of development in the coastal zone by recording their physical, chemical and biological consequences. Damages that would be readily observed on land are seldom noticed; wastes just seem to disappear. Also, there is no tradition of managing marine areas for conservation as on land. Often pollution of coastal systems originates in the open seas outside the jurisdiction of states. Because the ocean has been an 'open-access resource', competitive exploitation has been the norm. This led to regional and international conventions that impose a framework and laws (e.g. UNEP's Regional Seas Programme and the Convention on the Law of the Sea). Using resources in the coastal zone requires integrated management (including both land and water components) and protection of some natural areas, so that the zone may yield the greatest benefit to present generations without losing its potential to meet future needs. Preserving genetic diversity is a matter of both ethics and economic survival. Genetic diversity is needed to sustain and improve agricultural and fisheries production, to keep future options open, to guard against harmful environmental change, and to secure the raw material for scientific and industrial innovation (Salm & Clark 1984). 71 Conservation of biodiversity in Africa Human activities have dramatically increased the intensity, pace and kind of environmental changes that lead to habitat loss and pose severe adaptive challenges to marine organisms. Response to these changes includes drastic declines of many fisheries and extinction of several species. The loss of species and ecosystems obscures equally important threats to genetic diversity, which is essential for species survival in a changing environment. , ough fewe~ ir filr more t I ntrod uction The coastal waters of many African countries contain some of the world's richest ecosystems characterised by coral reefs, seagrass meadows, mangrove forests, estuaries and floodplain swamps. Because of the economic benefits that can be derived from them, the coastal zones teem with human settlement. Without doubt, the greatest risk for marine ecosystems is their proximity to such high concentra tions of humans. ine biologil :ions than in des diversity i. diversity in 4, Martens 1 most vulner: The tremendous increase in the human population and the intense activities to meet economic needs have placed an immense pressure on natural resources, and have led to their misuse or abuse. Anthropogenic destruction of resources, frag mentation and change ofhabitats, release ofpollutants, introduction ofalien species and climate change are now more rapid, intensive and widespread than natural changes (Dugan 1990, WRIIIUCN/UNEP 1992). Although it has often been assumed that marine organisms are more resistant to extinction than terrestrial ones, this assumption only reflects a shorter history of intensive exploitation and our relative ignorance of the marine realm. The coastal zones of most nations are subjected to increasing pressures manifested by a variety of human activities, notably urbanisation, industrialisation, fishing, coastal aquaculture, mining, waste disposal, oil drilling, shipping traffic and tourism (Bryceson 1990, Dugan 1990, Martens 1992, Portmann et al. 1989, Saenger et al. 1983, UNEP 1982a-c, 1984a,c, UNESCO 1981, 1986). This mix of water-based and land-based economic activities has put considerable stress on those coastal resources that are the very basis of their viability. The fast pace of technological development and economic activity has not allowed for the evolution of appro priate attitudes and structures to minimise the exploitation that poses a threat to marine biodiversity. On the other hand, the information necessary for proper resource management has remained inadequate and competing human uses have often remained unrelated and unplanned. Also, the majority of the population subsisting in coastal systems are the rural poor, and any change will affect them first (Dugan 1990, WRIIIUCN/UNEP 1992). This paper gives an overview of the main causes of biodiversity loss in African coastal ecosystems. ral aspects 0 .,crs and their ond, coastal .·st wastes ever. I: 1 be very vari habitat duri ~m (Dugan 1S p ine conserve "'Years (WRI! ulation incre , only recent f=oastal zone 1 ages that we pt to disappe lServation as c outside the j )urce', compe ernational COJ mal Seas Progl I ling resources :h land and wa e may yield ential to mee ics and econo icultural and f ful environr ustrial innoval IJ' 70 di~ cur on land 1 ,1st nearly the! greater divel d. Further, 6: be more c I1IUCN/U Conse",ation oj biodiversity in Africa Threats to marine biodiversity The ways that humans threaten marine biodiversity can be grouped into proximate threats and root causes; the former are driven by the latter. Concerns may differ from region to region, reflecting local situations and priorities. Proximate threats The main types of human activities that damage marine organisms and ecosystems are: over-exploitation, physical alterations and habitat loss, pollution, introduction of alien species, and global climate change (Dugan 1990, UNEP 1982c). Over-exploitation Coastal ecosystems are an important source ofessential products for mankind, such as foods, medicines, raw materials and recreational facilities (Dugan 1990, Martens 1992, Saenger et ai, 1983, Salm & Clark 1984, UNEP 1982a-c, 1984b,c, 1985a, 1989). The ever-growing exploitation of coastal resources is a reflection of the population increase, the most important root cause for biodiversity loss. Tourist populations, generally concentrated in few areas, increase the local exploitation for specific crustaceans such as lobsters, crabs and prawns (Schood & Visser 1991). In theory, virtually any marine organism, even the slowest-maturing or least fecund species, could be exploited sustainably as long as no more are taken than reproduction can replace. However, today's exploiters are numerous and their technologies powerful. Current fishing activities exceed sustainable yields on a large number of traditional fishing grounds, especially in coastal areas and on continental shelves (Sanders et ai, 1990). Most commercially valuable marine populations are now over-exploited. Because most methods used to catch targeted fish and shellfish are unselective, large numbers of invertebrates, fishes, sea turtles and marine mammals are caught and then discarded. Dynamite fishing and poisoning are unselective and kill large numbers of vertebrates that are then not harvested (IUCN 1990, Salvat 1987). Marine mammals, seabirds, sea turtles and many invertebrate species are also threatened by direct exploitation. Marine mammals and sea turtles are long-lived, slow-reproducing organisms whose attractive products make them extremely vulnerable to over-exploitation. Nesting turtles on the beaches are defenseless and more readily captured than at sea, while their eggs are easy to collect. Many seabird species are colonial nesters, making them vulnerable to large-scale egg collection and hunting (IUCN 1990, Salm & Clark 1984, Wells 1988). Many marine organisms, including corals, sponges, molluscs, echinoderms, puffer and trigger fishes, and turtles, are collected widely for curios or jewellery (IUCN 1990, Martens 1992, Wells 1988). The over-fishing ofshallow inshore populations can have serious local effects on these species and their habitats. Other over-exploited marine products are stony corals for building material and mangroves for fuelwood and timber (IUCN, 1990, Hamilton & Snedaker 1984, Martens 1992, Salm & Clark 1984). These activities have contributed to species 72 declines and ca Martens 1992, 1 Over-exploitatic returns but also trophic relationsl involving multif species frequent! food webs and ~ Physical altera Because organisl each place are Cl conditions are al the biological co cleared to make agriculture (Dug Not only does SI but many comme grounds (Salm II benthic commur by the trawling sediment (Salvat Upstream defore load in runoff. Tl threatens coastal their feeding or r turbidity reducin occurred, longer substrate, with COl ecosystems that f reefs, are especial decreases the dive which leads to a sustain (Blom 19~ hand, reduction in due to modificati coastal ecosystem shrink and fish pc ~he constant or fn iiiversity. Dams d !Valuable coastal h: ''the Senegal and N I, at their deltas and 1 . in fish catch (Dug. Causes of biodiversity loss in coastal ecosystems X:lmate , differ fstems llction [,such artens 985a, )f the aurist tation 991). ~cund ction erful. ional et ai. 'ited. large then rs of also red, lely and lird ion fer :N ms rld :4, es declines and caused structural damage to the habitats (Dugan 1990, ]accarini & Martens 1992, Martosubroto & Naamin 1977). Over-exploitation not only reduces specific populations and causes lower economic returns but also causes genetic changes in the exploited populations and alters the trophic relationships among species. Marine organisms are part ofintricate food webs, involving multiple trophic levels at several spatial and temporal scales. Removal of species frequently leads to losses of other species and to changes in communities, food webs and key species (Beddington 1984, McClanahan & Muthiga 1988). Physical alterations and habitat loss Because organisms are adapted to specific abiotic environments, the conditions in each place are crucial in determining the community of species that live there. If conditions are altered, there will be corresponding changes in the composition of the biological community. Vast areas ofmangroves, estuaries and beaches have been cleared to make way for coastal development, industrialisation, aquaculture or agriculture (Dugan 1990, IUCN 1990, UNEP 1982a,c, 1984b,c, UNESCO 1979). Not only does such development destroy rich mangrove and estuarine fisheries, but many commercially valuable species depend on these coastal habitats as nursery grounds (Salm & Clark 1984, UNEP 1985b). Trawling profoundly disturbs the benthic communities on the seabed. Disturbance includes physical damage caused by the trawling gear and reduced photosynthesis caused by resuspension of sediment (Salvat 1987). Upstream deforestation and careless agricultural practices increase the sediment load in runoff. The addition of anthropogenic sediments, especially silts and clays, threatens coastal systems by smothering or burying marine organisms, clogging their feeding or respiratory organs, coating photosynthetic surfaces, or increasing turbidity reducing the light available for photosynthesis. After sedimentation has occurred, longer-term effects can follow from changes in the particle size of the substrate, with consequences for the structure of the benthic fauna. Shallow coastal ecosystems that flourish in clear waters, such as seagrass beds and fringing coral reefs, are especially vulnerable to siltation. An increase in sedimentation usually decreases the diver~ity of coral species and the percentage of living coral cover, which leads to a decline in the diversity and number of fishes that the reef can sustain (Blom 1985, Giesen & Van der Kerkhof 1984, Salvat 1987). On the other hand, reduction in sediment and nutrient supply from the altered freshwater inflow, due to modification of river basins, can have dramatic effects in estuarine and coastal ecosystems. Deltas and their mangrove, marsh and mudflat communities shrink and fish populations can decline rapidly. Estuarine ecosystems depend on the constant or frequent freshwater inputs that determine their productivity and diversity. Dams change the amount and timing of freshwater input and reduce valuable coastal habitats (Dubois et ai. 1985, IUCN 1990, UNESCO 1981). On the Senegal and Nile Rivers, dams reduced the freshwater and sediment discharge at their deltas and lead to coastal erosion, salt water intrusion and significant decline in fish catch (Dugan 1990). 73 Conservation of biodiversity in Africa Other activities causing physical alterations are coastal mining and construction, mangrove clearing for agriculture and aquaculture, dynamiting of reefs causing serious beach erosion, and dredging of inshore waters. The negative impacts of tourism include trampling, boating and anchoring on the coral reefs (Martens 1992). Pollution A complex mix of anthropogenic pollutants pose a serious threat to estuaries and coastal waters. Anthropogenic nutrients enter the coastal waters as runoff from fertilized agricultural and silvicultural lands, sewage effiuents including domestic and industrial wastes, dredging, vessels dumping cargo at sea and atmospheric deposition of air-borne pollutants. Nitrogen and phosphorous are the most common limiting nutrients in coastal waters and their availability determines species composition and growth of plants, which in turn affects the entire ecosystem. In most developing countries, sewage is discharged untreated or only partially treated into rivers, lagoons and coastal waters via short outfalls, most of which were installed with little attention to advanced planning. Human sewage (together with pathogenic organisms) and agricultural runoff (with increasing amounts ofinorganic fertilizers) are particularly rich in nitrogen and phosphorous, and form the major source of pollution in coastal waters. The biological process initiated by such nutrient enrichment--eutrophicationcan have far reaching effects such as: increased primary production, changes in plant species composition, dense and sometimes toxic algal blooms, changes in structure ofbenthic communities, and conditions of hypoxia or anoxia (GESAMP 1990, Pearson & Rosenberg 1978, Portmann et ai. 1989, UNEP 1982b). Contamination of inshore waters by sewage also causes serious public health problems (portmann et ai. 1989). Coral reefs grow only in clear waters with low nutrients. Nutrient pollution creates algal blooms that cloud the water and limit the sunlight reaching the corals. Chemicals, such as trace metals, radionuclides and petroleum residues, become toxic environmental contaminants when discharged in excessive concentrations. Many contaminants become associated with sediments and may remain sequestered until resuspended by waves and currents or until sediments are disturbed by dredging activities. Synthetic compounds are becoming increasingly important chemical pollutants in the sea. Among the most persistent ones are the chlorinated hydrocarbon pesticides used in agriculture (PCBs, DDT), dioxins from incinerators and paper mills, organotins (TBT) used as antifoulants, and oil dispersants that are toxic and cause the oil to sink onto benthic communities (GESAMP 1990). The main concern for toxic chemicals are the long-term effects as many of them are persistent in the environment and become concentrated through the trophic chain. In exposed marine organisms, toxins can cause death, disease, reduced reproductive success and developmental aberrations. 74 massive side-ef on oceans a rbons, accumula1 ,~- increase of glob ring patterns ( peratures may m 8 to 340 cm) elf and the Ii I1IUCN/UNl ~ects 'gether, these ch. .vironmental cha all-bodied rapid water temperatl production and g becoming a wide -.il levels rise, coast. ill recede unless! ~inity distributior ., astal currents ar lange in intensity Causes of biodiversity loss in coastal ecosystems 10n, sing ts of tens and rom ~stie eric nost ines ltire mly it of rage ,ing )us, n510 ;10 \1P ni~ms nts. ght me ns. esby lOt :ed ralat 0). :10 HC ed Communities in contaminated ecosystems have reduced species diversity as more sensitive species are the first effected and tolerant species, relieved of competition or predation, proliferate. Crude oil and gas production, although bringing in important foreign exchange earnings and local employment, have significant impacts on coastal areas (IUCN 1990, UNEP 1984a). Industrial and domestic solid wastes are often dumped in mangrove creeks with consequent outflushing of rubbish and toxic products (GESAMP 1990, Martens 1992). With the increased use and disposal of plastics, solid wastes are now more than a litter problem as plastic debris causes widespread mortality in marine species through entanglement or ingestion (Carr 1987).Because of their strength, buoyancy and durability,plastic products account for more than 50% of all anthropogenic debris items found at sea and on coastlines. Introduction of alien species Introduced species are responsible for many extinctions, especially on islands where the indigenous biota usually lack the necessary defensive or competitive capabilities. Many marine organisms are transported by humans, either intentionally for aquaculture and private collections or accidentally from fouling and ballast-water of ships. Some of these exotics are now dominant species in coastal communities where they have replaced native species (Carlton 1989, GESAMP 1990, WRIIIUCN/UNEP 1992). Global climate change A massive side-effect of air pollution~lobal warming-may have profound effects on oceans as greenhouse gases, especially carbon dioxide and chlorofluorocarbons, accumulate in the atmosphere. The greenhouse effect will not only cause an increase of global temperature but also change the distribution of heat thereby altering patterns of ocean circulation, precipitation and storm tracks. Warmer temperatures may also cause a rise in sea level of about 140 cm (estimates range from 8 to 340 cm) during the next century, due to thermal expansion of the water itself and the likely melting of icecaps (GESAMP 1990, IOC 1992, WRIIIUCN/UNEP 1992). Together, these changes could have serious effects on coastal biodiversity. Rapid environmental change is a common cause of species impoverishment as it favours small-bodied rapid-producers over large-bodied long-living organisms. Increase in water temperature will also affect temperature-dependent processes such as reproduction and growth. Coral bleaching, due to prolonged higher temperatures, is becoming a widespread phenomenon and significantly reduces coral growth. As sea levels rise, coastal erosion and severity offlooding will increase so that coastlines will recede unless stabilised by dykes or sand influx. Changes in rainfall patterns, salinity distributions and temperatures will alter rates of delta sedimentation, and coastal currents and upwelling patterns are likely to shift geographically and change in intensity. 75 Conservation of biodiversity in Africa A common consensus is that global warming will make the dry areas drier and wet areas wetter, bringing about a climate of extremes. Coastal wetlands, being highly populated, are likely to suffer the most visible impacts as their landward movement may be hindered by the ever-growing development of coastlines. With the loss of this coastal fringe, the species it contains will be lost too. Many islands would be completely submerged if the more extreme projections of sea level rise occur. Root causes Biotic impoverishment is an almost inevitable consequence of the ways in which the human species has used and misused the environment. The main root causes of biodiversity loss lie in: demographic pressure and unsustainable use of natural resources; economic policies that fail to value the environment and its resources; insufficient knowledge and its poor application; weakness in legal and institutional systems (Dugan 1990, McNeely et ai. 1990, UNEP 1984b, WRIIIUCN/UNEP 1992). markets. Man purification, s Because these that decide w et al. 1990). " degradation 0 Economic pol radation as th increase envir products. Ano both the use a often the local out of plannin Deficiencies i Scien tists still innumerable 0 exists it does r develop policit coastal biodive 1992). Except most marine re databases on m policy-makers, difficulty in coc jurisdictions an A final difficul~ resource conSUl campaigns. I Human population growth and unsustainable use of resources The global human population is quickly rising towards the 6 billion mark. Almost 70% of this population lives near aquatic systems, especially coastal zones. In countries with high fertility rates, about half of the populations is under 16. The resulting demographic momentum in coming years, due to this large number of people reaching their reproductive age, means that the global population will continue to grow for at least the next half-century. The rates and magnitude of this growth depend on social and economic measures, especially on economic development in developing countries (WRIIIUCN/UNEP 1992). As numbers increase, the consumption of renewable and non-renewable resources has a higher rate of increase. The recreational use of coastal waters is also increasing, in some areas representing the major industry. Coastal tourism generally shows peaks in tourist numbers in certain areas, especially those with high biodiversity such as coral reefs, and at certain times of the year. High tourist numbers put additional pressure on coastal biodiversity through excessive food, energy and water consumption, physical alterations of the environment (infrastructural development, boating, trampling), and cultural alterations (Schoor! & Visser 1991). Ironically, this environmental degradation and congestion may destroy the main natural assets on which tourism development is based. Economic systems and policies that fail to value the environment and its resources Conversions of natural systems to farmlands or industrial areas take place due to the urgent need for economic land use. These developments are often economically and biologically unsound because they are implemented regardless of sustainability, and because natural habitats are commonly under-valued. There are several reasons for the mis-valuation of biological resources. Many resources, such as food, fuelwood and medicinal plants, are consumed directly and never enter 76 J#ak legal an, Most COuntries: resources, but ea or tourism. Eco: including localciplinary and im nication and i developing cour ments to ensure (Dugan 1990,!v legal constraints fragmented and grated and regio biotic communil Causes of biodiversity loss in coastal ecosystems nd wet highly rement loss of ,uld be cur. which causes latural >Ufces; Itional JNEP I.lmost les. In 5. The ber of n will Ide of lOmic mbers ligher some aks in Ich as tional connent, y. this :ts on its ue to omiss of ~e are such enter markets. Many values of coastal biotopes do not have markets, such as water purification, storm surge protection, and nursery grounds for fisheries products. Because these are 'free goods' they tend to be ignored in economic calculations that decide whether such biotopes should be conserved or developed (McNeely et al. 1990). The result is a systematic bias favouring development and hence degradation of coastal ecosystems. Economic policies in many African countries contribute to environmental degradation as the need for foreign exchange earnings often forces countries to increase environmental exploitation, such as for wood, minerals and marine products. Another aspect is the inequity in ownership and flow of benefits from both the use and conservation of biological resources (McNeely et al. 1990). Too often the local communities, who are dependent on the natural resources, are left out of planning but in the end pay the price. Deficiencies in knowledge and its application Scientists still do not have adequate knowledge of coastal ecosystems and their innumerable components (Martens & Jaccarini 1990). Even where information exists it does not flow efficiently to decision-makers, who have often failed to develop policies that reflect the scientific, economic, social and ethical values of coastal biodiversity (Dugan 1990, McNeely et al. 1990, WRIIIUCN /UNEP 1992). Except for research on commercially important resources, until recently most marine research had scientific rather than resource-management goals. Few databases on marine subjects exist that are accessible or informative enough for policy-makers, especially on a regional and international scale. An additional difficulty in coordinating information collection and transfer relates to overlapping jurisdictions and competition among agencies concerned with marine resources. A final difficulty is often public reluctance to accept policies that reduce excessive resource consumption, which shows an urgent need for more public awareness campaigns. ~ak legal and institutional systems Most countries have different institutions that are responsible for managing coastal resources, but each ofthem focuses on only one aspect such as agriculture, fisheries or tourism. Ecological realities, however, clearly call for a cross-sectoral approach including local-community participation. It is only quite recently that multidisciplinary and institutional collaboration has been established to facilitate communication and information exchange among all concerned groups. Many developing countries lack adequate environmental laws and enforcement instruments to ensure protection of the environment and sustainable use ofits resources (Dugan 1990, McNeely et al. 1990). Largely because of these institutional and legal constraints, biodiversity conservation and management has typically been fragmented and restricted to specific protected areas or species. However, integrated and regional approaches are needed to address the habitat needs of whole biotic communities in relation to development programmes. 77 Conservation of biodiversity in Africa Conclusions Although some coastal ecosystem loss is inevitable and can even benefit man, much is both detrimental and avoidable. Only by increasing awareness of the value of coastal ecosystems and designing economic incentives that encourage people to support conservation, will the rate of biodiversity loss be subsequently reduced. References Beddington, J .R. 1984. The response of multispecies systems to perturbations. Pp. 209-225 in R.M. May (ed.) Exploitation of marine communities. Berlin: Springer-Verlag. Blom, J. 1985. Decline of the Malindi-Watamu Reef complex. 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Over-grazing may r, is a major problem i vegetation regrowth alists have been enCi Deforestation is assc the industrial couo1 logging in tropical a so its affect is greate: countries to lose mt logged annually in I and 1980; by 1980 ~ Rural industries (suc and charcoal bumin about 1 ha of woodl: about 0.2-0.3 m 3 oj industries. Charcoal productiof is estimated that 4 t< preferred by charcc informal traders use out of control causin to have reduced fore Besides extinction 0 economic consequel reservoirs, fuelwood 80