Kruseman 1953). The majority of the 3,244 ...... most common reason for arrested successions after forest conversion to grass- land in the tropics. There are ...
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CHAPTER 1
CONSERVATION OF SPECIES AND HABITATS: A MAJOR RESPONSIBILITY IN DEVELOPMENT PLANNING D i c h Mwllrr-Lhmbois Kwwata Kartawinata Linda Lco Handley
T H E CONCERN
Development of land and water resources usually implies conversion of natural habitats to other uses. People rarely realize that converting habitats to other uses will deprive some biological species of their homes and life resources. Even where this loss of living space is recognized, however, it is often dismissed as unimportant relative to anticipated progress through development. After all, the requirements for human development must be met first. But what about the other species around us? After a little thought, it becomes apparent that human beings carry a heavy burden of responsibility not only for improving their own development but in safeguarding, as much as possible, the coexistence and welfare of contemporary life companions on this planet-the many different species of plants and animals around us. Good development planners will include habitat and species conservation in land-use planning, and the conservation zone concept proposed in this chapter is a practical means for accomplishing this essential function. Species are defined here as groups of individuals who can survive only in populations and through interbreeding with similar kinds of individuals. This similarity in kind refers to certain outward (morphological) and inward (genetic) similarities, which make species relatively distinct biological entities. Another unit of concern is habitat, defined as the home (space) and life resources of species. Over the past few years. rare and endangered species have received much international attention. O u r concern in this chapter. however, is with the whole spectrum of species occurring in any area considered for development. In nature, species rarely occur alone. Instead, they usually form species
2
Natural Systems for Devtlopmenr
Figure 1 . I . T h e four higher levels of biological organization: individual organism, population of similar individuals = species, community, and ecosystem. The lower levels (not shown here) are organs (roots, Icaves, etc.), then tissues. then cells. which are common to all organisms (adapted from Dansereau 1963). O n the right-side diagram. each profile segment ( I , 2. 3) can be called an ecosystem, or all three together can be called an ecosystem. There are different ways to define size and kind of ecosystems and communities. Similar communities are community types and similar ecosystems are ecosystem types.
combinations called communities. As such, several species belonging to the same community may occupy the same habitat. Species do interact to various degrees with other species in the same community. The community, in turn, interacts with its habitat. This interacting unit of community and habitat is an ecosystem. The four levels of biological organization with which planners need to operate in conservation planning and management are, in order of increasing complexity, the individual organism (mortal), the species (as an interbreeding population), the community (as a combination of species occupying the same habitat), and the ecosystem (as an interacting unit of community and habitat) (figure 1.1). Human beings are but one of the many biological specieson this planet, our only habitat. As cohabitants with all other species, we form a copmunity with them, except that most of our coexisting plant and animal species have much more restricted distributions. This characteristic alone makes them more vulnerable. There is a great interdependence among species. A small number of them, the domesticated animals and cultivated plants, provide us with our daily needs. Habitat conversion often occurs for the primary purpose of increasing the space and life resources for domesticated plants and animals. This, in simplified terms, may be known as agricultural development. Agricultural development, however, involves a great deal more. Among
h e r thine, it involves understanding the requirements of domesticated plants and animals, knowledge about their rates of productivity and reproduction capabilities, and knowledge about their adaptation to different environ. mental conditions and resistencc to pest organisms. The survival of a species depends on the interbreeding conditions of its individuals and on the continued availability of a specific set of life resources. , be Hence, species are dynamic entities that can increase, d e c ~ or destroyed. For exampk, domesticated plants and animals are selected for special products and high yields. It is often the case that in the process of domestication they have lost some of their capacities to withstand new stresses from diseases or other pest organisms. Pest organisms thrive in situations that are less restrictive to them, and they adapt rapidly to new situations. Therefore, domesticated plants and animals need occasional genetic revival through interbreeding with their wild relatives. All of this is more or less common knowledge. But what is rarely appreciated is that this knowledge has come largely from an understanding of how wild species survive in their natural habitats. T o what extent can we deprive these wild species of their living space without risking the loss of many valuable species by extinction? Which species are most valuable, and which are less so? Scientists are far from being able to answer these questions. For example, in the recent past, species diversity has been equated with ecosystem stability. This was an oversimplification. An ecosystem with high species diversity, that is, one containing a large number of species, each with approximately similar quantities of individuals, is not necessarily more stable than an ecosystem with low species diversity. What is more important for ecosystem stability is the dynamic balance among the species and their environment. In natural ecosystems this balance has developed over time under the influence of regional evolutionary stresses and the competitive and complementary adjustments made among the species themselves. Evolutionary stresses may include such things as periodic fires, floods, storms, frosts, droughts, insect pest outbreaks, and grazing. Where the species groups or biological communities have been exposed repeatedly to such stresses, they have likely become adapted to them. Adaptation requires development of coping mechanisms in the species themselves as well as in their relationships to one another. Therefore, species removal from an adapted regional assemblage will sooner or later result in loss of stability. Many scientists agree that species loss is one of the greatest contemporary environmental problems. Also, adding new species from foreign ecosystems indiscriminately without their naturally established control factors is likely to result in disrupting an established balance. It is important to maintain natural areas as sources of species that can restore damaged ecosystems. Unfortunately, the continuing value of natural habitats and the wild species groups they contain has so far been appreciated only by scientists and by peo-
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Natural Syatcms for Development
ple who feel strong ties to their natural environments. In general, such natural areas may appear to be "idle land," that is, land without any tangibly productive value or purpose. This schism in concept-to consider natural areas as idle land instead of as important resources of genetic materials and biological balance factors for maintaining regional ecosystem stability-has resulted in part from a communication gap between scientists and development planners.
Every local development contributes to the world trends of either conservation or accelerated loss of species and habitats. Current world trends reveal both positive and negative aspects. O n the positive side, development and conservation are now seen to be equally important in alleviating human misery and producing a more economically stable world. Poverty often produces habitat and species loss that in turn reinforces poverty. If farmers are landless, they may clear soils unsuitable for subsistence agriculture, leaving denuded, ruined soils and degraded watersheds. Poverty forces people to use whatever resources they can get (e.g., grass for herds, forested lands for subsistence farming and firewood) with no thought for the future. The resulting land degradation in turn ensures future poverty. It is being realized, therefore, that conservation of natural resources is not in opposition to development but is the keystone of development for long-term sustainable use. Likewise, rational economic development gives people the opportunity to plan for the future and to create a healthy, sustainable environment for themselves and their children. Formerly, species conservation was seen as an elitist pursuit, focusing on a few conspicuous organisms such as elephants, whales, and a few rare plants. In this form it could be the luxury only of wealthy nations. The high degree of integration and mutual dependence in nature, however, has become increasingly apparent. Man is just as dependent upon and integrated with the natural world as any other organism. Food, clean water and air, and freedom from disease and pests are all related to the maintenance of a balanced, healthy, and diverse environment. Even people living in highly industrialized areas are directly dependent upon the natural and agricultural resources of the countryside for their daily needs. Hence, development and conservation ideally should go hand in hand. O n the negative side, conceptualization is far ahead of realization. Singlegoal development and concurrent habitat loss is still more the rule than the exception. The demands of a growing, hungry population may force development schemes with short-term goals. The pressures for new agricultural land may, for instance, outstrip the ability of governments to plan adequately and
2 to +ssers best methods and sites. Pruent laws md customs of land tenure and mourn rights may restrict rational development. M m y dinerent estimates arc available on the number of species being lost annually and on the amounts of forested lands lost every year. Regardless of which set of estimates is taken as most accurate, the amounts arc large. The most drastic habitat and species losses arc now occurring in the tropics and are caused by population expansion. Raven (1981) reported that lowland tropical forests have been reduced to half their former area in the past 100 years and that every year an additional area the size of G n a t Britain is removed. At this rate of habitat loss, a fourth of all the plant and animal species in the world could be extinct within the next thirty yean-most of them untested for possible use by human beings. Tropical systems may be least resilient to degradation. While many tropical ecosystems are highly productive, they also are often based upon a delicate balance of conservative nutrient cycling carried out by the integrated actions of a diverse flora and fauna. In temperate forests, a few tree species may dominate large tracts of land. Many of these trees are wind pollinated, and wind dispersal of seeds is common. There may be only a few kinds of large animals. The underlying soils in temperate zones may accumulate large stores of nutrients and organic matter, and when cleared for agriculture, these soils may be fertile for many generations. Because of the soils' chemical composition and high organic matter content, depleted fertility can be restored with fertilizers. These soils are capable of holding applied nutrients until they are needed by crops. In contrast, tropical forests often consist of hundreds of tree species with individuals of the same species occurring as sparsely scattered individuals. For example, as many different kinds of plants and animals occur in the small tropical country of Panama as are found in all of Europe (Raven 1981). The growth and reproduction of both plants and animals is dependent upon complicated interrelationships and food webs. Nutrients and organic matter are tied up largely in living organisms and may be cycled rapidly among them with little storage in the soil. When the organisms (plants and animals) are eliminated through natural death or land clearing, so are the nutrients. Agriculture on such soils may be sustainable for only a short time. Many tropical soils lack significant amounts of the phosphorus needed for plant growth and may be acid and infertile as well. They also may lack the ability to store temporarily applied fertilizer nutrients. Thus, even expensive fertilizers may not improve depleted fertility. Because of the low amount of organic matter and the chemical composition of many tropical soils, they may lose texture when cleared and cultivated. In extreme situations this can lead to poor drainage and bog conditions, or to permanently hard, brick-like (lateritic) soils impossible to cultivate. Thus, a site that sustains a highly productive tropical forest may be totally inappropriate for agriculture.
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Natural Systems for Dcvdopment
Not all tropical soils respond in this poor fashion, but because many of them do, the planner's choice of development sites and land uses is absolutely critical for sustainable yields. While tropical forests are at once highly productive and diverse environments, ill-considered development can turn them into sterile, unproductive landscapes incapable of supporting either natural systems or agriculture. Because species diversity in the tropics is high, species loss also is great. Although the need for development is paramount, so is the responsibility for conservation. T h e only way to reverse the trend of tropical habitat depletion is on a case-by-case basis. The conscientious and dedicated participation of each developer, planner, and government involved is required to meet this objective.
The practical realities of developing countries are that exploitation of natural systems must occur so that the human condition may be improved. At the same time, we know that human beings are an interdependent pan of the environment. The exploitation, therefore, must be accompanied by conservation and the assurance of sustainable use, sometimes at the sacrifice of some immediate economic gain. Conservation is more easily rationalized and accepted when species and habitats have commercial market value and when they are scarce or unique. Conversely, when value is speculative or in the distant future and when the number or areal extent is large, planners will find it diflicult to include conservation measures in development projects. Efforts to conserve species and habitats should be justified insofar as possible by valuation in monetary terms so they can enter into benefit-cost analysis calculations. Even plants and animals that have no direct market price can be treated as resources. However, there may be a trap in putting values on all species. The trap is that once a value is set, then any use of higher value competing with conservation will prevail. For example, Gosselink, Odum, and Pope (1974) have painstakingly established the value of a certain tidal marsh (when in its natural state) at $82,940 per acre (for services such as a fish nufsery or aid in removing pollutants). T h e problem comes when use for industrial or residential construction may command a higher value and the marsh is then destroyed. The fall-back position of some conservationists is that communities and species should be conserved simply because they exist; essentially an ethical viewpoint. An equally valid and only recently appreciated viewpoint is that species are valuable because they are integral components of a valuable system. Their individual values may be small or even unknown, but because they perform a function in a larger complex system, they should not be m k -
hrty discarded. Likewise, communities of species arc functional components in larger. more complex ecosystems. At this level, the value of habitat conser-tion becomes apparent. Even if a particular system (e.g.. a wetland) has a high& monetary value when developed, its value in the overall landscape (e.g., flood control) may be greater. Aside from economic considerations, decisions of conservation are often made for noneconomic reasons (e.g., scenic value, national heritage, aesthetics, unknown potential value). T o appreciate this not-entirely pragmatic side of natural area conservation, the planner must have a vision of how the landscape should look when development is completed. Since the planner has one of the most important responsibilities in shaping future landscapes (i.e., the ecosystems of man), he must not only be a well-trained, educated, professional with awareness (if not formal knowledge) of sociology, economics, and biological ecology, but he also must be a visionary with a high concept of culture. This includes a sense for both human history and natural history. However, the planner's efforts in creating long-term sustainable developments through careful site assessment and conservation need not be carried out alone. Various agencies and institutions exist for the sole purposes of assisting in this effort. These will be discussed later in the chapter.
There is little argument that domesticated plants and animals are our main renewable resources. But what about wild species? There is no general recognition that they have resource use value. For example, in most land resource inventories, emphasis is placed on such ecosystem properties as climate and hydrology, soils and landforms, current land use (e.g., agricultural crops, grazing, forestry, urban use), and geology, particularly the mineral resources. The nearest to a consideration of wild species in resource inventories are the forest type maps. These often give some information on where wild species can be expected in a given landscape, but they rarely provide information on species composition and the kinds of wild species found in the forest-covered areas. This is because existing forests are usually considered a major resource, mostly for their timber value. Associated wild species, plants and animals, are ignored in most resource inventories. As a result, we usually know very little about these other wifd species in any spe- cific area, except for what has been revealed through long-term use by local residents or through scientific investigations by botanists and ioologists. Local residents usually know some of the resource values of many wild plants and animals in their home range. Unfortunately, this folklom knowledge has often not yet been transferred to either scientific description or the specific land development program of an area. Ethnoscience is a potential means of acquiring much useful planning information. I
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Natural Systems for Development
There is, however, a problem in placing a value on wild species. Once an economic value is d i x o v e ~ d no , one will doubt the resource value of a wild species. As soon as the economic value is known, the species will be evaluated for its economic rank. Some species then become more valuable, others less so. There is nothing wrong with this in the sense that one must always determine priorities, but with wild species there may be much at stake due to the vulnerability of some of the organisms. Wild species are living organisms, just as the human species is. Some have adapted well to living on this planet. others may perish, and some are full of surprises. One surprise is that wild species help us to survive and maintain an amiable existence on this planet in more ways than the obvious. For example, it was a pest species, the common bread mold, that yielded penicillin, a most important antibiotic. Other wild species, often obscure plants, contain useful drugs, medicines. and insecticides. They teach us how they have managed to adapt to adverse conditions, provided we are willing to learn from them. This learning cannot take place once those particular teachers are gone, and human existence becomes deprived by this loss. Unfortunately, many wild species are eliminated easily by human development projects. If human beings do not allow for their living space, most wild species (except pests) will be eliminated through habitat conversion. While we ponder the elusive value of wild plant and animal species around us, we have attained a better understanding of their worth in systems rather than merely as individual species. By systems we mean many species occurring together as communities, where individual species interact with one another, or as species and habitat systems (i.e., as ecosystems). In the latter, the added complexity is in their interaction with the physical environment. For example, a forest-with its trees, other plants, and animals-can maintain itself year after year because of another group of species, which is less visible but nevertheless important in the ecosystem. These are the microorganisms (bacteria, fungi, soil arthropods) living in the soil surface. They work generally as decomposers; that is, they convert the dead leaves, branches, and animal feces on the ground into mineral nutrients. These then become available for reabsorption and plant and animal production. If microorganisms did not function in this way, the community of plants and animals would soon cease growing and reproducing. The forest community would eventually suffocate in its own waste. Different species of microorganisms have specialized into particular functions (niches). For example, the nitrogen fixers specialize in trapping gaseous nitrogen from the air. They then use some of the nitrogen for themselves and make the rest available to the plants. T h e n are many other species interactions that add to the full functioning of ecosystems. For example, rnycorrhizae, root-associated fungi, act as extensions of the root systems of certain trees, thus providing for a greater absorption of soil nutrients.
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~ ~ n w r v a ~olSpecier ion and Habitats
Microorganisms ue widely available as a rule, so that their services are free rnd do not normally need special attention in conservation. But there are situations where their services break down, for example, in poorly drained or polluted places. Knowledge of ecosystem functioning has taught scientists that nothing can be taken for granted. It could even happen that an important decomposer species may be lost in an area through pollution. This could slow down land productivity; or, in plantation forests, it could cause a fire hazard due to &I accumulation of undecomposcd plant litter. There is good reason to believe that all species are indeed contributing to the functioning of our planet as an amiable habitat, and it would be unwise to consider any species dispensible before its full range of activity is understood. But what about pest species that can take advantage of human disturbances, such as disease organisms, mosquitoes, and weeds? In natural systems, they are usually kept in balance so that they rarely become epidemic. Pest species become rampant only when natural checks and balances are absent. Human activity is the greatest single cause for this. Natural checks and balances are often provided by other species that are parts of the ecosystem. For example, mosquitoes are kept in balance by insect feeders such as birds and small reptiles. Mosquitoes may even prefer feeding on wild animals and ignore human beings as long as wild animal hosts are present. Enlarging mosquito habitats (which, unfortunately, is easy) and eliminating bird, reptile, and mammal habitats (which is also, unfortunately, easy) result in mosquitoes becoming bothersome pests. Attempts to eliminate mosquitoes by spraying may solve the problem only temporarily. Pest species are hard to eradicate. They usually develop spray-resistant strains and then return in full force. This is an ongoing and constant battle. New insecticides have to be developed. In this battle, other wild species may again come to the rescue by providing insecticidal substances contained in formerly unknown wild plants or by providing appropriate habitats and preferred pest hosts. Beyond the role of the individual species-of which there is so far only fragmentary knowledge-wild species groups (i.e., communities) and ecosystems as natural units have cenain well-established functions in developed landscapes. The following section gives examples of the importance of species and habitat conservation in development planning.
IMPORTANCE OF WILD SPECIES AND HABITATS: EXAMPLES
All crop species were once wild species. The richest varieties of flora and fauna of wild species are in the tropics, most of them in large, unexplored tropical forests. In the Malesian region (Indonesia, Malaysia, the Philippines, and Papua New Guinea) alone. an estimated 25,000 species of flowering
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Natural Systems for Development
plants occur (about 10 percent of the world flora), and many of them arc still unnamed and undescribed (Raven 1981). Besides crop species, wild species are of great value to human beings for a variety of other purposes. Examples of current and potential uses of wild plant and animal species follow.
Timber and Wood f'rodc~cfs Currently, the use of forest species is limited to particular groups of primary forest species of a certain size (diameter greater than 30 cm). However, there is also a growing tendency to use trees of smaller diameter (about 10 cm), thus approaching the stage when all tree species in the forest will be of economic value. Secondary forest species in Southeast Asia have been used infrequently so far. although there are numerous fast-growing species that have economic potential for plantations. The more common ones are anggerung ( T r m o h hlis), kayu raja (Endospmnum diadcnum), mahang (Moraranga species), binuang (Duabanga moluccana), laban (fitex pubescens), jati seberang (Peronemu canescens), albisia (Albizia/alcafaria) and jabon (Anthocephlus chinemis). Many of these can reach 30 m tall and 50 cm in diameter in a relatively short time, such as thirty years. Only a few (e.g., Albizia falcaturia, Anthoctphalus chinensis, and T r m orientalis) have been used successfully in reforestation programs so far. The use of pine species (e.g., Pinus mcrkusii and Pinus caribuea) is preferred, thus limiting the diversity of future forest products. For instance, high-quality and fancy timber for cabinet making, which has a high market value, can be obtained from angsana (Pfcrocarpus indicus) and kayu kuku (Pmcopsis mooniana); two species whose use was previously little known. The former, which has been successfully planted in the greening programs of Singapore and Jakarta, can be propagated with ease. There are many other primary and secondary forest species currently unknown economically that have potential and need further investigation. P a l m and Bamboos
Palms and bamboos are important forest products in addition to timber. In Southeast Asia there are about 550 species of rattan palms, of which about 350 are species of Calamus. Rattans are used for such items as furniture, basketry, fishtraps, mats, hats, and ropes, and for the edible "cabbage" of most rattan species (e.g., Dannonorops nulanochytes and Dannonorops hulltliana). Most rattans are collected from undisturbed rain forests in which they are sparsely distributed. These inevitably are diminishing in abundance with the decreasing extent of undisturbed forests. Commercial and village cultivation have been attempted with little success. There is an assured world market for rattans. Currently, rattan exports bring millions of dollars annually to many South-
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I
esrc Asian countries. The loss of natural and seminatural forests will diminish b e supply ofrattans and impoverish domestic life. Several p n e r a and species of starch-producing palms play an important role in the life of local people. T h e x indude sago palms (Mrtroa$on sagu and Mdroqhn rwnfhii) that grow wild in swamp forests. T h e x species arc important starch producers, and their starch is the staple food in the Moluccas a n d parts of New Guinea. They are also important for house construction in Southeast Asia and the Southwest Pacific. Another species is N @ fnrticans (nipa palm) that grows in mangroves and is known to produce sugar. As yet no effort has been made to cultivate and manage these palms. Southeast Asia has more than 200 species of bamboo that are used for building material, furniture, handicraft, musical instruments, basketry, paper, and edible shoots. Only a few species (e.g., Lkdrocalarnlrr strictus and Bambusa arundinacca) are now used in the production of commercial paper. Shoots of the bamboo species Cigadochlw after, Dcndro~famusasper, Dinochlw scanains, and Bambusa aulgaris are edible. In the tropics, bamboo shoots have not yet been utilized on a commercial scale as they are in China. Fruit P h n ~
Many tropical fruits are of forest origin and, in fact, many of them are still harvested from the forest. In Southeast Asia, for instance, there are at least 105 species of fruit trees, of which about a third are growing wild, a quarter are being cultivated, and the rest are both being cultivated and growing wild. These include such species as rambutan (Ncphcliium Inppaccum), langsat or lansones (Lansiwn donusticum), durian (DUGribethinus), mango ( M a n g i i a species), mangosteen or manggis (Carcinia mangostana), oranges, limes, lemons, pomelo (Citrur species), Rambai (Baccaurea species), and banana (Musa species). Only a few of them have been improved by selective breeding. Several genera contain more than one species with edible fruits that have a great potential for cultivation, but are known only locally and in wild forms. For instance, MangiJera has forty species in Malesia and the Solomon Islands, but only five are in cultivation. Out of twenty-seven species, six species of Durio produce edible fruits, and only one is widely cultivated in Southeast Asia. Rambai (Baccaurca) has about sixty species; at least twenty have edible fruits, and only four are known to be in cultivation. In the eastern part of Indonesia and Melanesia (Fiji, Vanuatu, Solomon Islands, and Papua New Guinea), nuts are more important than fruits. These indude kenari nuts (Canarium indicum and Canariwn salomoncnse) and tropical almonds (Tmninolia species). Similarly, in tropical America there are many species with edible nuts that are of economic importance, such as Brazil nut (Berihollctia ucelsa). The National Academy of Sciences (1975) has singled out the most important tropical species with edible fruits and nuts that are still underexploited and have great economic potential.
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Natural Systems for Development
Many of the tropical species, especially those growing in forests, are of economic importance as ornamental plants. The successful multimillion dollar Singapore trade in orchids testifies to the fact that orchids are among the most valuable ornamental plants. Many species have been brought into cultivation and commerce, and many commercial varieties arc genetically based on wild species. Wild orchids thrive best in undisturbed primary forests. Another group of valuable plant species growing in tropical forests is the ornamental palms. Lipstick palm ( C ' h c h y s h m ) , for example, has a high market price in Indonesia. It grows mostly in the peat swamp forests of Borneo and Sumatra, and its existence is threatened by intensive logging of these forests. Other species that may be valued as ornamental plants are trees and shrubs with attractive shapes, flowers, or colorful young leaves (e.g., beef wood or iron wood [Casuarina], clerodendron, gardenia, hibiscus, and rhododendron); herbaceous plants and climbers (e.g., alpinia, begonia, cyrtandra); and ferns (e. g., Aspleniurn, Cyathca, and Ntphrolepsis). Other Plant Species Increasingly, environmental managers are looking to nature rather than to technology for solving pollution problems. The entire course of biological evolution can be seen in some ways as problem solving for species survival. When a new pollution problem arises, a careful examination of natural systems may reveal that nature already has a solution. Two wild grasses recently have become very useful for cleaning sewage water. In Hawaii, paragrass (also called Californiagrass, Brachiaria mufua) was long considered a weed and a nuisance, growing wild in wetlands and certain waste places. This grass is used as cattle fodder and now provides an eficient means for stripping sewage emuent of nitrogen and phosphorus, thus making the water clean again. It is found throughout the tropics, and its use is not limited to Hawaii. In subtropical and temperate regions, careful ecological research revealed that natural stands of the salt marsh cord grass, Spartinu alhzflora, were very effective in cleaning sewage water, and natural stands of this grass are widely used now. These are only two of the many possible examples of wild wetland plants that now have valuable uses (National Academy of Sciences 1976). Research is now planned to test joint grass (Paspdurn distichurn), another wild pan-tropical grass that grows in brackish water. This plant shows promise for cleaning saline wastewaters. Jojobe, guayole, amaranth, and tepary bean are being cultivated in the United States and Mexico for their oil, rubber, and food value. They were used by indigenous peoples, then long forgotten and treated as weeds. The
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conservation dSpecia and Habitat8
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value of rubber t m r was recognized a littk more than 100 yean ago. Rubber growing is now a major industry with the existence of hundreds of thousands of plant species. Out of these, less than 200 are now cultivated. Surely many more will be cultivated as soon as research proves the value of the remaining plant species.
Many people in rural areas of the tropics still obtain animal protein from wild sources ranging from various invertebrates, fish, birds, and large mammals. In some cases, they exploit animal resources commercially, although it is done with traditional methods. The daily per capita percentage of dietary protein obtained from wild animals ranges in the tropics from 20 to 90 percent (Prescott-Allen and PrescottAllen 1982), with an average of 45 percent for Africa, % percent for Asia, and 30 percent for America. Aquatic animals predominate in Asia; land animals in Africa and America. In Africa the species of exploited wild land animals are more diverse than in Asia and America. They include such species as giant rats (Thryonomts species), grey duiker (Syluicarpa grimmia), brushbuck (Tmgclaphw strictus), royal antelope (Ntotrugus pygmanu), black duiker (Caphalopus nign), and monkeys (e.g., green monkey, [Cnopitkcus anthiops] and red colobus [Colobw badius)). In Asia and America the wild land species exploited are limited in number. In Asia, for instance, the species commonly hunted for food include wild pigs (Sur barbatus, Sur wrrucosur, and Sur scr.fa), mouse-deer (Tragulus species), deer (Rcrsa species), and wild cattle (Bos jauanicus). Many of these wild species that can be used as the source of food and for other purposes have potential for domestication. A large number of aquatic species are harvested from the wild for local consumption and for export, using traditional as well as modern techniques of harvesting. The species commonly harvested in Asian waters include mackerel (Rastrtllign species), Spanish mackerel (Scombtromorur species), round scad (Dccoptrruc species), sardines (Surdinella species), and anchovies (mostly Stoltphorus species). Only a few species have been domesticated; for example, milkfish (Chunos chunos), shrimp (Macrobrachyum species and Pcnnanrr species), and tilapia (Tillopia mozambica).
Plant Producfs A variety of valuable chemical compounds can be extracted from wild plant species. Undisturbed tropical forests contain far more species (including useful ones) than any other ecosystem on land. Forests could have the potential to
3 14
F'atural S v s ~ r r n sfor DcvcIopment
become a .major source of raw materials for future biochemicalpharmacological technology. Several chemical products from plants arc already known to have commercial importance. Compounds that are found in all plants (primary metabolites) include lignin, cellulose, and protein. It is now possible to extract edible protein from leaves. The South American tm. L r u c ~ l alcucofephalu (ipil-ipil), is known to have a high protein content. It becomes weedy in other tropical regions. It has been used for animal feed (National Academy of Sciences 1975) and is used for human food in Indonesia. I t is likely that there are many other species, especially other legumes, that have high protein contents and may be exploited commercially in the future. Lignin, the main component of all wood, is used in the manufacture of plastics, ion-exchange resins, oil stabilizers, rubber reinforcers, fertilizers, vanillin. tanning agents. stabilizers for asphalt emulsions, dispersants for oil-well drilling, and for ceramics processing. Lignin also can be broken down into phenols, and is used in making phenolic resins, polyesters, and other aromatics. The cost of these processes is approaching that of current petrochemical production. It is believed that the world demand for polymers can be satisfied from wood without difficulty and that synthetic oil can be manufactured from plants in the foreseeable future. Whitmore (1980) believes that the prospect for such an undertaking in the humid tropics is great. Climatic conditions there make possible a continuous supply of raw materials derived from large plantations. These can be established on poor soils, which are unsuited for intensive agriculture. Many chemical compounds occur in only particular species, giving rise to the different smells and tastes of plants. These compounds are referred to as secondary metabolites and include chemicals that form insecticides, essential oils. drugs and medicines, gums, latex, and resins or waxes. Commercial insecticides occur in the roots of many members of the bean family (Leguminosae). These plants have been used traditionally as fish poisons. Other potential pest control chemicals are insect attractants (pheromones) and insect molting hormones (ecdysones) and are produced by various plants (e.g., the bark of many of the Podocarpaceae produce ecdysones). These naturally occurring insecticides have advantages over synthetic ones because they have a low toxicity in higher animals, are biodegradable, and do not accumulate. Numerous essential oils produced by wild plants are used in the perfume and flavor trades or as a source for other compounds in the chemical industry. It is cheaper to obtain chemicals from plants than to synthesize them. Production of essential oils that have commercial importance occurs in South Amenca, North Africa, and West Asia. For instance, Paraguay quaiac wood oil is obtained from the tree Bulnuio sarmimti (Paraguay), rose wood oil from Aniba rosaedora and Ocotca prctiosa
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,.
(Brazil). t6lu balsam fmm Mpoqlon
6ahon)wn (Colombia). American styrax
from Lquidmnb4r s t p ~ P y 0(Honduras, Guatemala, Mexico), cedamood oil (the Himalayas), and from Ccdw af&nlica (Algeria, Morocco), Wrus &ra Junipcrw prorma (East Africa). Southeast Asia produces essential oils from a few species, such as gandapura ( C o u l h i a species), sandalwood (Sontalwn album), cayuput (Mclaleuca k o d n d r a ) , Eucalyptas species and gaharu (Aquilaria malacccl~se).Recently, b w r y (1977) discovered that essential oils from Cinnumomum pWIcctwn (cinna(medang) from Southeast Asia a n comparable mon trees) and Li&m &$ra to those from Brazil. He suggested these as an alternate source because these species were not known as essential oil producers previously. Certainly there are numerous wild species having potential and awaiting further screening for useful compounds. Tannin- and dye-producing species, which include the beefwood or ironwood tree (Casuarina equiseiifofia), soga (P~ltophoruminmnr), bakau (Rhuosphora species), and kesambi (Schlrichera ohsa), are mostly wild plants. especially those growing in the forests. Other wild species are known to produce resins (e.g., camphor trees [Dryobalanops species], meranti [Shorea species], laural tree [Cafophyffumspecies], damar (Agathis species]) and gums (e.g., mindi [Azndirachta indica], monkey pod [Acacia species], kelumpang {Stcrculiof d i d a j ) . Latex production characterizes a few families. Some of these are of commercial significance, such as Manilkara zapoh, C O Un~i i h , and Couma macrocarpa from Central and South America, and Q e r a species and Palaquium gutta from Southeast Asia. This latex may become important as the raw material for producing valuable chemicals.
Animal Produds Wild animals provide a diversity of useful products. Some-such as alligators, turtles, musk oxen, llamas, and certain African grazing animals-are now raised for cropping. Alligators are hardy animals that are useful for their meat and hides; various alligator parts also are used for tourist items. Musk oxen are recently domesticated animals that produce musk used in perfumes and a fine wool for cloth. Similarly, llamas now are being raised in North America for their wool and hides. Until recently, llamas had only limited use in a small part of the mountainous areas of South America. . Some of the wild grazing animals of the African plains (e.g., springbok and wildebeest) are a better source of meat than imported cattle. Not only are these animals adapted efficiently to using the nutrient-poor grasses often found in these regions, but they also are not susceptible to the diseases that plague cattle. As in many other instances, these wild animals-a natural part of the ecosystem-are well suited to the plains and thrive with little or no expensive technological input from man.
7
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16
Natural Syatems for Dcvelopmenc
Insects also can be directly useful, besides fulfilling such indirect functions as pollination and scavenging. Silkworms long have been cultivated. More
recently. New Guineans have begun ranching butterflies for a profitable trade in biological specimens by growing the plants and creating the habitats favored by the species of butterflies that they want to sell.
Although widely used for many years, especially in rural areas, traditional medicines have been looked down upon or ignored by governments of developing countries. Recently. however, this attitude has changed, and developing countries often encourage use of indigenous traditional medicines. Even the World Health Organization (WHO) regards this as a rich cultural and natural resource that should be used more fully to increase the availability and effectiveness of health services, especially in rural areas. In many countries. traditional methods now are practiced along with modem medicine. Large factories have been established to manufacture traditional medicines. Although traditional medicine is still subject to scientific and technical evaluation, it has proved to be effective in many cases. The growing interest in rehabilitation of traditional medicine means a greater reliance on, and demand for, medicinal plants. In the past almost all medicinal plants have been harvested from the wild. Large-scale plantations do not exist, and only haphazard planting occurs in home gardens. In Java, for instance, eighty species of medicinal plants have been recorded (Lubis and Prana 1980). In Indonesia more than 1,000 species have been recorded as medicinal plants (SteenisKruseman 1953). The majority of the 3,244 species described by Heyne (1950) for Indonesia, and the 2,432 species by Burkill (1935) for the Malay Peninsula have medicinal use. Phytochemical screenings have shown that many plant families contain valuable chemical compounds such as alkaloids, cardiotonic glycosides, and saponins. Several species of the family Apocynaceae, for instance, contain chemical compounds that have medicinal value against heart disease, malaria, and nerve disorders. During the past decade commercial interests in traditional drugs and in plants containing steroids have increased. This interest especially has involved diosgenin (which has contraceptive value) and anticancer drugs. Diosgenin, it has been found, occurs in species of ginger (Costu) and yams (Dioscorea). The species of ginger, however, are the most promising source of diosgenin. Trials are now underway to cultivate these plants on a commercial scale. Many species have become rare because of high demands for use in traditional medicine and, to a smaller extent, for export, thus leading to overexploitation. Several species that are important ingredients of the Javanese
traditional medicine (or jamu) arc now r u e and doomed to extinction (e.g., Curte m , C w n u lorn'agii, ~ CUM o i d j b r a , Cibdiwn barom&, and Vwconso p d - a ) .
There are many species-other than c e d s , corn, and potatoes-that produce carbohydrate consumed by people in the tropics. The most widespread ones cultivated in the tropics include cassava, sweet potato, yam, taro, and sugarcane. There are other wild species that have not yet been used widely as sources of food or for other purposes. The most outstanding group is the yam family (Dioscoreaceae), which contains about 170 species. One hundred and fifty of these belong to the genus Dioscorca. Only Dioscorca alaia and to a lesser extent Dioscorea csculmh are widely cultivated. Before the introduction of cassava and sweet potato, Dioscorca a h was the main source of carbohydrate in Southeast Asia. Many other species in this genus have edible tubers but they are only known locally, and their occurrence is rather restricted. They can be brought into cultivation more widely, or they can be utilized as genetic stocks for the improvement of other cultivated species. Many of them, for example, have better carbohydrate characteristics and protein contents. They are species that tend to be overlooked in many areas because their uses are little known. They are likely to disappear and need conservation. Another important carbohydrate producing species is taro (Colocasia esculmh), which has been cultivated rather widely. There are several related wild species and genera (e.g., A h i n and Xanthosomu) that have been used to a limited extent as sources of carbohydrates. They represent a wide range of genetic stocks for breeding. Metroxylon s a p and Mctroxylon rumphii are two species of palms growing in freshwater swamps in Asia, particularly in Moluccas and New Guinea. They are a carbohydrate source and have been consumed and harvested from the wild by people in the area. Many other food plants grow wild and in semicultivation, such as various species of palms (e.g., Arenga pinnula, Nypofrulicans, and Eugrssona utilis), grasses (e.g., sugarcane and rice), legumes such as winged bean (Psophocarpus tetragonolobur), jackfruit family (Artocarpus communis and Ariocarpus ekzsticus), and aroids (e.g., Amorphophalus species, in addition to Colocark, Alorasia, and Xanthosorna mentioned above). These are important for both direct (e.g., f d ) and indirect uses (e.g., breeding purposes).
Wild species can be exploited not only for direct use as sources of timber, food, medicine, and industrial raw materials, but also for indirect use as the
18
Natural Systems for Dtvelopmcnt
source of genetic stocks in the improvement or rejuvenation of cultivated plants and domesticated animals through breeding. Cultivated plants and domesticated animals have relatives that are still growing wild or in x m i domestication. These related wild species and semidomesticated varieties are a storehouse of good genetic characteristics (e.g., high yields, fist growth, resistance to pests and diseases, and tolerance of extreme environments). Many cultivated species and varieties have a narrow genetic base as a result of generations of highly selective breeding in cultivation. It is no longer possible to rejuvenate them by crossing among themselves. The only way is to turn to nature, where wild species and varieties with different genetic traits abound. The following examples indicate the role and importance of wild species in the improvement of cultivated crops and domesticated animals. Plants
Rice-A number of good quality rice varieties have been and are still being developed by the International Rice Research Institute (IRRI) in the Philippines and by the national agricultural research institutes in various Asian countries. With the spread and adoption by farmers of the new varieties, there is a danger of losing locally cultivated varieties that have genetic diversity. Thus the conservation of an indigenous genetic pool becomes an immediate necessity. As new varieties are usually developed to meet certain needs, each variety becomes specific in its characteristics and, consequently, each has a narrow genetic base. For further improvements, the genetic base must be widened. This can be accomplished only by hybridization with other varieties or species still containing diverse genetic materials. The cultivated rice species ( O v a satiua and Oryza glabenrima), their weed races, and the eighteen wild species of the genus OIyra have a rich genetic pool for rice improvement. Explorations of local varieties and wild species have been conducted in Africa and Asia. By the end of 1974 the IRRI gene bank contained 35,000 accessions, cultivated varieties and breeding lines of Oryza satiua as well as a collection of 3.000 populations consisting of O v a glabmima strains, wild species, genetic testers, and mutants. It is known that in Africa the cultivated rice, Oryza glabmima, has several wild relatives. In Asia the cultivated rice, Oryza satiua, is associated with several weed races. They have been evaluatedand screened for desired characteristics such as resistance to disease, insects and drought, tolerance to adverse soil conditions, improved yield, photosynthetic efliciency, and nutritive quality. Outstanding sources of disease resistance were found, for instance, in agronomically poor types such as Oryza niaara. Banana-Bananas ( M w a species) grow wild in tropical Asia, especially in the Malesian region (Indonesia, Malaysia, Papua New Guinea, and the Philippines). A number of cultivated varieties and various hybrids occur in this
,'
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t
d
~ ~ ~ r v a tofi Species o n dHabitats
19
also. Banana plantations, however, were established mainly in Central pnd South America in the late 18001. Only two cultivated varieties, Gross Michel and Cavendish, have been acceptable for export. Gross Michel was widely grown commercially because of its adaptability to shipment as whole bunches. Its cultivation, however, was discontinued as unprofitable because of the infestation with Panama disease (fusarium wilt) that became a serious problem after its commercialization. The Cavendish variety was substituted, but it was susceptible to a root disease and heavy losses resulted. Other diseases now pose potentially serious threats. Control costs of the pests and diseases have been substantial. There have been no effective chemical and cultural ways to control these pests and diseases. The solution is to grow resistant varieties. Two wild subspecies have been used for breeding: Musa a c u m i ~ t asubspecies banksii from New Guinea and the South Pacific, and Musa acurninata subspecies malaccmsis from the Malay Peninsula. The cross between these two subspecies produced several progenies, one of them resistant to the wilt disease. Further crosses with existing cultivated varieties and selection and testing of the progenies subsequently produced a cultivated variety that has many good features and marketing prospects (e.g., disease resistance, good forms, storage and ripening characteristics). Sugarcane-Sugarcane consists of three species: Saccharurn officinarurn, k c h a r u m sinmsc, and Saccharurn barbm'. The first is a species with a thick stalk and high sugar content, and originated In Southeast Asia. The latter two have a thinner stalk, less sugar content, and originated in C h i d J a p a n and India, respectively. Saccharurn oflcinarurn has been used intensively in the tropical sugar industry and has been the major source of genetic stock in sugarcane breeding. The other two species have been grown only in marginal climates. The considerable increase in sugarcane yields during the 1930s was due to the introduction of varieties produced by hybridization between species of Saccharurn. Hybridization resulted in the development of varieties that are resistant to diseases and drought and are tolerant to cold. The wild species that have been used in breeding programs of sugarcane are (1) a Saccharurn group consisting of three species (Saccharurn spontaneurn, Saccharurn robusturn, and Saccharum sanguineurn) and distributed in the Solomon Islands, Indonesia, Papua New Guinea. Asia, and Africa; (2) a Saccharurn group that embraces the genera Snccharum, Erinnthus, Scltrostachya, and Narmga, occurring in India, Indonesia, Southeast Asia, and ChinaIJapan; and (3) a group that includes the genera Imfmata, Erianthus, Ripidium, Eccoilopus, Miscanthus, Miscandidium, and SrIc~oslo~hya. Rubber Plants-Rubber. Hevea bratiliensis, is native to Central and South America and especially the Amazon Basin. The rubber industry. however, developed best in Southeast Asia, especially in Malaysia and Indonesia. It is now the largest agricultural industry there, is rivaled in recent years only by
3
Natural Systems lor Dcvrlopmrnc
thc timber and oil palm industries. and plays an important role in the economy of these countries. The first rubber plantation was established about 1876. Plantinq marerials were based on 22 seedlings planted in the Singapore Botanical Gardens. Breeding programs to improve latex yields have been carried out by rubber breeders. and yield levels have been greatly improved. These programs, however. were based on the narrow genetic range of the twenty-two seedlings initially introduced. Narrow breeding objectives and the planting of only a few elite clones have resulted in genetic erosion and loss of available germ plasms. It was soon realized that continuing yield increases depended upon conservation of the genetic variability. The current genetic stocks available in Southeast Asia that are and will be used in breeding programs are ( 1 ) cultivated varieties currently used in plantations, ( 2 ) obsolete cultivated varieties or those not in use and preserved in seed orchards. ( 3 ) wild species, and (4) special genetic stocks. A wild species currently in use is Hcom spruceana, which is crossed with Heuca brariliensis to improve its latex properties. Special genetic stocks are species that have secondary characteristics absent in the existing cultivated populations. Species in this category that are used currently in breeding programs include Hcuea brasilicnsis from Peru. He~*ca benlhamiana from Rio Negro, and Heucapauctflora. All of these are resistact to leaf diseases, and the last two are resistant to secondary leaf fall. The genetic variability of rubber needs to be increased because the existing variability is small compared to that in the place of origin. In view of the current rapid rate of land development, such as in Brazil, genetic conservation is especially urgent. Since World W a r 11. plant collecting expeditions have been carried out in South America. Two of these were sponsored by the Food and .4griculturc Organization (FAO) and the Association of Natural Rubber Producing Countries. Potato-The potato originated in South America. It belongs to the genus Solanum. which contains about 2,000 species. T h e tuberous Solanum consists of 154 wild and seven cultivated species. T h e common commercial potato is Solanurn /ubcrosurn, in which two subspecies are recognized: lubtrosum and and,erna. The potato \\-asdomesticated thousands of years ago in South America and has bern tiisprsrd to all parts of the world by human beings. Selection for higher yields seems to have occurred as soon as potatoes became cultivated plants. Potato brreding in Europe took place after the introduction of cultivated poraroes of the and~qmagroup (Solanum rubrrosum subspecies andigena) in the sisternth century. The early breeding effort was concerned with producing varier irs with thr ability to produce tubers under Europe's long summer days. By the nineteenth century. numerous varieties already were produced in Europc and Sorth .?\merica. A later stimulus for breeding new varieties of potatcws tvas thr severe cpidrmic ol' potato blight and wart diseases. There
Conservation dSpccicr and Habitats
21
in using a wider genetic b a r in breeding. This led to the formation of many new varieties tbat have been developed through hybridization between wild species and the newly introduced andigma group. Thus, there are new elements or characters not found originally in the tubrrosum group (Solanwn tuberoswn subspecies t&onun). C u m n t l y ~rdcroswn varieties are used as the foundation in brteding high-yielding varieties, whereas andigma group varieties, cultivated species, and wild species are used as a source of other desired characteristics not present in the f&osum varieties. Breeding programs are now concerned with producing high-yielding varieties with good pest and disease resistance, tolerance to a variety of environmental situations, and a good quality of tuber. The 154 tuberous wild species and seven cultivated species occurring in South America are easily interbred. These are rich genetic stocks for the improvement of potatoes. T o conserve the wild and primitive cultivated species, the International Potato Center has actively conducted collecting expeditions in Chile, Bolivia, and Peru. As of 1975, 4,000 wild and primitive cultivated species had been evaluated for use by breeders. Orchids-Orchids have many species and grow naturally in tropical forests. In Southeast Asia alone there are about 5,000 species. They are of economic importance as ornamental plants, as evidenced by the successful multimillion dollar trade in Singapore, and only a very few are used otherwise (e.g., vanilla). The first orchid hybrid was produced in 1856. An immense number of hybrids are now produced in Asia, especially in Malaya and Singapore. Commercial domestication and hybridization of wild, local orchids began about 1930. The breeding objectives were to produce attractive hybrids that are free flowering with commercial value. One early product of hybridization was, for example, the famous Vanda, Miss Joaquim-a hybrid between the local species Vanda hookm'ona and Vanah toes. Crossing it further with Vando hoobiana produced another hybrid called Vanda roopcri. Important genera currently used in hybridization include Ararhnis, Dmdrobium, Renanthrra, Spathoglottis, and Vanda. Many species have been brought into cultivation and commerce as well as used in breeding to produce commercial varieties. They almost all come from primary tropical forests where they grow on old trees. The supply of wild orchids thus depends on the existence of primary forests. Consequently, conservation of wild species also means conservation of their habitat. Corn-Almost all strains of corn that grow in tropical lowlands are susceptible to a devastating virus disease complex. Year-round cultivation in the tropics increases the persistence of this disease complex. There is, however, one primitive cultivar of corn originating in the Caribbean that is resistant to the virus complex. Through interbreeding with this primitive strain, many other strains of corn have become resistant to the disease complex.
was increasing interest after 1925
Kcrrntly a spc-ies of teosinte. a grass that is a wild relal~vro f cctrn. was disc.c~\.crrtlgrcnvinq wild in rural Mexico as a weed. Unlike domestic corn. howr.\.rr, i t is rrsistant to virus diseases. tolerant of cold weather. qrows !car round. and contains larger amounts of oil and protein than corn. It is now beinq used in breeding programs to upgrade hybrid corn production. T h i s plant is known to exist in only one place on about four hectares of land. .4 hast, o r misplaced development of this one small area could have depri\.ed the world o f this genetic insurance against hunger.
\\.bile examples of plant breeding a r e numerous. those of livestock breeding with \ ~ i l dcounterparts are scarce. Only 1wo examples from developing countries arc docuri~cnted.although there may be other, undocumented cases. In Israel the animal called )a-ez is a hybrid between the desert goat and the ibcx. It has the hardiness and the ability to go for days without water of the former, and i t has the tastiness of the latter. In India, two wild tasar silk moths. Anthrrara roylri from India and Anfherata p ~ y from i China, have been crossed to producc .-lnthrrota proylei. T h e silk produced by this hybrid is said to be the finest ever produced in India. a n d the hybrid can produce more silk than its parents. that is. 170 percent by weight and 94 percent in filament length. This can increase considerably the income of rural people in India and China who traditionall! practice tasar silk culture by leaving silkworms. including wild ones. to feed on wild trees. T h r r r arc many wild or semiwild animal species that have thc potential to be a source of genetic stock for crossing with domesticated ones. T h e seladang a n d bantens of Southeast Asia are good examples of wild forest animals that could be crossed with domesticated buffalo and cows, respectively.
T h e preceding discussion dealt with the value of wild species in general; however, emphasis was placed on wild species indigenous to a particular area. .4lien spc*cies. also known as exotic o r introduced species, are those brought into a n area through human activity. C r o p species a r e often alien species, and their transfer to nonnative habitats has been of variable success. Some have been successful, such as the transfer of radiata pine from a small island off the coast of California to New Zealand. but others have been less so. If the new environment closely matches the native environment, alien crop species are likely to be successful. Negative forces often must be overcome when the new environment differs. For examplc. diffrrnces in the daily light o r temperature regime may require the
~onrcrvationof Speck md Habitats
23
breeding of varieties that arc better adapted to the new environment. Commonly. more critical factors arc insea pests and d i x ~ in s the new environment. As pointed out before, this often requires going back to the area of origin and searching for specific insect- or disease-resistant relatives for interbreeding. But such relatives may be unavailable or may have disappeared due to habitat conversion. It is, therefore, always less risky to use indigenous crop species because they have become adapted to their particular areas and ecosystems over a long period. It is not only the risk involved in maintaining alien crop species, but also the costs of expensive pesticides in particular. Moreover, the extra cost may increase as pest species adapt to particular pesticides. Indigenous crop species will, therefore, become an increasingly attractive alternative. In addition, they are significant in creating greater independence from foreign aid. While alien crop species belong to the generally cared-for renewable resources, alien wild species often become undesirable elements in new landscapes. Most weeds are in this group. They are defined as aggressive plants that grow in places where they should not grow. Some can do considerable damage to crop plants by choking them out, while others deprive domesticated animals by destroying the value of pastures. Alien wild animals can do similar damage. Rabbits introduced to Australia from England during the last century are an example. They nearly destroyed the Australian sheep industry until a myxomatosis disease of rabbits was introduced. The introduction of wild species, which may be done willfully or accidentally, is often accompanied by negative results because such species lack the control factors that keep them in check in their native ecosystems. The spread of water hyacinth is perhaps the most dramatic example of an introduced plant creating problems. Native to South America, this attractive flowering plant was introduced to Nonh America and to Southeast Asia during the last century. Today it chokes waterways, depletes the oxygen needed by aquatic animals such as fish, and provides a breeding place for mosquitoes and human parasites. T h e control of water hyacinth outside its natural range is now a major economic burden in many countries. Similarly, paperbark trees (Melakuca lcucadtndra) were introduced into the Florida Everglades to turn useless swamps into timber lands. Now the paperbarks are displacing native vegetation at a fast rate and control measures have been totally ineffective. Species of Eucalyptus are currently a popular fast-growing tree for timber plantations. Eucalyptus may represent a real fire hazard, as these trees contain volatile essential oils. Even when introduced species do not become major weed pests or fire hazards, their establishment eliminates habitat for native species of plants and animals that may be better suited to the area in the long term. Alien species are not inherently good or bad; however, they present an eco-
24
S.rtural S\strms tor 110 rloprnen~
loqical risk that should br avoidc-d wherever possible. l'he risk is that they are transferred into a nc.w ecosystem where the checks and balances are different from those ol'their native environment. In contrast. indigenous species will not become economically detrimental unless their natural system is effectively destroyed through overdevelopment.
If we are serious about conserving our wild animal species. we must provide them with at least some of their natural habitats. A zoo will not do this, because most wild animal species change their behavior patterns there and many of them d o not even breed. Those that do breed are limited in choice of mates. This also limits [he genetic diversity in their offspring, which in turn may result in a loss of resistance to diseases and eventual domestication or total dependence on man. Conservation then will become an extreme economic liability because of the constant care required for species maintenance. Natural habitat here means that the site in question is covered with natural vegetation, that is, communities of wild-growing plant species. These plant species provide wild animals with food and shelter if a few other conditions are also met. These are (1) that their necessary food plants are still present in the habitat, (2) that there is enough habitat area to support the wild animals, and (3) that there is sufficient habitat diversity to include water and other basic requirements. Fortunately. wild animals-like plants-form communities. Therefore, conditions that provide sufficient habitat for the dominant species. such as elephants (in Sri Lanka) may also provide sufficient habitat for other associated animal members in the community. such as buffalo, sambar (a large elk species), axis deer, and other grazers and browsers. Another principle in wild animal conservation is to maintain as much as possible the natural biological control system. For example, leopards are needed in Sri Lanka to keep the wild grazers in check; crocodiles. pigs, and jackels are important as scavengers in that they redistribute nutrients across the habitat. The latter function much like decomposers, as activators in the nutrient cycle. Other less dominant, less visible members of the animal community interact importantly with the plant community. For example, flying animals such as insects, birds, and bats often act as pollinators in the fertilization of plants. Rodents, monkeys, and other animals perform a significant role in distributing seeds. Plant reproduction and maintenance processes may suffer when significant pollinator or seed dispersal agents are not present. These facts argue strongly for the maintenance of total ecosystems, which should be the first goal in the conservation of wild species and habitats, a point
-nation
of Sprier and Habitats
25
thai has been emphasized also in the World Conservation Stra~egyof the International Union for the Conservation of Nature (IuCN) (1980). Different strategies may be needed for animal conservation, depending on the home range characteristics of the animal groups that arc considered most important for conservation. Wide-ranging terrestrial animals, such as elephants, need large terrains that a n particularly important in seasonal climates. Access to permanent water is most important in a territory where part of the range dries up periodically. In such environments it is necessary to at least allow for corridors (i.e., strips or belts of wild vegetation) between seasonally alternating home ranges. Comdors should be considered also where only partial migration between home ranges occurs due to less severe seasonality or alternate food sources. Such corridors permit contacts among herds so that interbreeding can persist. In the conservation of wetland birds, on the other hand, a network of smaller, individual habitats may serve as well or better than one large area. In the conservation of rain forest birds, a continuous area may be better than a network of smaller disjoint habitats. In all cases, it is important to draw upon the assistance of local experts and scientists to work out the best compromise so that suflicient remnants of animal ranges are maintained. An important element in the determination of tolerable minimum area is some knowledge of the carrying capacity of the wild vegetation and habitat for the wild animal species in question.
How can one judge whether a given area or habitat is suitable for certain kinds d development? This question leads to a consideration of the approaches to land assessment. These vary greatly depending on the expertise of the people involved. All too often the approach is merely an economic vision, and few ecological considerations are taken into account. Land assessment then becomes pure guesswork. Such guesswork, while saving money at the initiation of the project, can become very costly in the long run. There are numerous examples of serious failures because of poor approaches to land assessment prior to development. Development planning is a complex task requiring a balancing of socioeconomic considerations with land capability assessment. The latter is concerned with the inherent, long-term sustainability of the land for a desired set of uses. A proper ecologically based land assessment should take the natural vegetation into account as an indicator of land capability. The most important land components to be surveyed with the aid of aerial photographs prior to development are landform, climate, soil, topography, geological substrate, water relations (surface and underground), present land use, and the natural or wild
f
26
Natural Systems for D~vclo~rnenc
vegetation. The term natural or wild includes here both primary (or climax) and secondary (or successional and replacement) vegetation. Among these land components. soil, topography and vegetation arc the best indicators of the other components. They reflect, to a large extent, the climate of an area, its geological substrate variations, water relations, and potential crop possibilities and yields. Vegetation adds a special dimension as a dynamic biological indicator. Carefully surveyed, it can give information on the frequency and severity of past floods, on storm and lightning damage to be expected periodically, on the duration and intensity of drought periods. and other climatic variables and disturbance factors. These might include landslides, creeping slopes, and fire. Planning failures in the allocation of housing developments, for example, often could be avoided by taking into account the hazard indications that are imprinted in the vegetation cover of an area. Moreover, the vegetation patterns of an area usually give reliable and rapidly obtained indications of soil, water, and nutrient relations of different habitat and habitat sequences. As such, natural vegetation can be used just as soil surveys or, better still, in combination with soil surveys as indicators of the agricultural- and forest-use potential of an area. Vegetation surveys for land capability assessment have been used widely in tepperate regions, and appropriate methods exist and are being developed for the tropics (see panicularly Webb et al. 1976; also Mueller-Dombois, forthcoming).
In the preceding sections we pointed out a number of imponant roles of wild species, in particular those of native wild species. We also emphasized some of the functions wild species groups perform as biological systems, particularly in landscapes where much of the area is already converted to other uses. T h e term "natural area" is often used to designate habitats with their wild species groups, that is, their natural biological communities. A synonymous term is "ecological reserve." This term has particular meaning in developed landscapes, where such areas function as reserves for species with their ecologies still relatively intact and unimpaired by human interferences (i.e., with natural processes such as reproduction, growth, death of old individuals, competition, complementation and cycling of nutrients not being interrupted by human activity). "Natural area" does not automatically mean "reserve," but in the future all natural areas, whether large or small, undoubtedly will be considered reserves of natural or wild species groups. O n e of the better-recognized values of natural areas is their function as watersheds. Still, it is sometimes surprising even to the researcher how well natural areas or native ecosystems perform this function. Two examples may suflice-one in Sri Lanka, the other in Hawaii.
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Sri Lanka, the large dropshaped island at the south tip of India, lies in the a u t h Asian monsoon dimate. Its mountain region in the southwest quarter of &e island acts as a large watershed for the remaining three-quarters of the island. These are the north, east, and southeast parts, which are also known as the dry zone. The mountainous southwest pan, referred to as the wet zone, rises from sea level to the highest peneplain, a mountainous rolling hill country, slightly above 2,130-m altitude. Much of the lower wet zone is in wet-rice cultivation, while the mid-elevational area is converted largely to tea plantations. An earlier British ruling prohibited cutting the indigenous montane rain forest above the 1,520-111 level. This area has come under pressure for further agricultural development, however, particularly for pasture and for potato cultivation. A portion of the native forest on the highest peneplain (the Horton Plain area) was already converted to grassland ("black patana") during ancient times, but a sizable portion of montane forest was left. Rainfall measurements were made under the forest canopy and in the open (patana grassland) for two annual cycles (Mueller-Dombois 1972). Precipitation under the trees was greater than in the open during the dry season (February through March), a time when even the rubber trees drop their leaves in the wet zone regularly each year. In fact, during February, a time when the northeast monsoon rains have ceased, there is typically a short dry season all over Sri Lanka. The northeast monsoon brings rain to the dry zone starting in early October through December and January. Then follows the short dry season, often going into March. Thereafter, the spring convectional rains set in. A typical daily pattern occurs then, with bright sun in the morning and cumulus clouds and thunderstorms developing at noon. Heavy shower activity follows in the afternoon. This period gives way to the southwest monsoon bringing heavy shower activity, which usually lasts from mid-June through mid-September, causing occasional problems of excess water. Rainfall was greater in the open than under the forest canopy during the southwest monsoon. These two opposite trends (more water under trees during the dry season and less water under trees during the rainy season) illustrate an important function of forest vegetation as a regulator of surface water flow. This regulating function can be ascribed largely to the canopy. During February through March there is little rain, but low-moving clouds are intercepted by the tree canopy, which results in additional surface water. During shower activity, rainfall is also intercepted by the tree canopy until it is saturated; then it drips through. Intermittant periods of shower and sunshine permit canopyintercepted rain water to evaporate as soon as the sun comes out. Under these conditions, more water is received on the ground in open areas. Depending on the volume and branching pattern of the canopy, this quantity ofwater can be quite considerable. In the Sri Lankan watershed this works favorably, since more water is recharged to streams during the dry period and less during periods of excessive rainfall.
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Natural Systems for Development
Another perhaps even less expected regulating function occurred in the Hawaiian Islands. Native forest canopy died back significantly in two watershed areas, first on the island of Maui and more recently on the island of Hawaii. In both cases, it was expected that canopy decline would ruin watershed values for the sugarcane fields on the slopes below these montane rain forests. Apparently, no significant differences in water outflow occurred before and after canopy dieback. Two factors probably prevented a significant change. First, it was the dominant canopy species ('ohi'a lehua = Mefrosidmos polymorphu) that died, while the undergrowth plants remained alive with some tree ,reproduction occurring. Second, a major site change-formation of bogs-was noted in both cases. While bogs may function differently than well-drained soils under forest cover, they also regulate the surface water flow by acting like sponges, absorbing water during heavy shower activity and releasing it evenly. Thus, natural succession took care of the water regulating function in these changing Hawaiian watersheds, a service that cannot be expected from plantation forests.
The function of natural areas as species reserves has already been mentioned with regard to crop plants. We pointed out that lesser-known indigenous plants often have uses known to indigenous people, but that such species have not been widely exploited. This underexploitation relates to direct crop use or to use for pharmaceutical or other industrial products. The need to rejuvenate certain crop plants with their wild relatives was also pointed out. This option will persist into the future only if natural areas are provided, in the form of species reserves or gene pools, in development planning. So-called gene banks. which are established to preserve seeds, are an important step for the preservation of wild relatives of crop plants, but they are not a substitute for natural areas in which natural processes can continue. Botanical gardens, arboreta, and zoos are valuable gene banks with limited purposes. In an ecosystem context, the use of a wider range of indigenous plants and the rejuvenation of crop plants with their wild relatives are restoration processes. Such restoration needs constant attention to prevent the degradation of modem agroecosystems, as degradation is a continuous natural process. The remedy for this is the preservation of natural areas with wild species to serve as reservoirs for agricultural restoration. The same natural areas, however, can serve to restore degenerating or damaged ecosystem components. If the remaining natural areas in a developed landscape are not too small and fragmented, they serve in providing plant material that may invade areas damaged through landslides, fire, or
conuwation of Species d Habitur
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floods and prevent excessive soil erosion. Pioneer and successiona) species a n not available f m l y in developed landscapes that lack natural areas. For example?.on the north island of New Zealand, where vast areas were convened to rad~atapine plantations, land scars often heal very slowly. While this may be due to exposure of substrates with imbalanced nutrients, it is also a result of plants which are available for invasion. Ordinary weeds are unable to invade extreme soils, while native species adapted to them are able to do so. This is well demonstrated on Hawaiian lava flows and ash deposits and also on old tropical rain forest soils with aluminum toxicity. Native species often can reoccupy and grow successfully on such extreme soils because they have adapted to the soils over a long evolutionary time scale that involved thousands to millions of years. Another example that demonstrates that adapted successional species are important, but not always available, occurred in the Sri Lankan black patana mentioned previously. This montane grassland forms a stable community next to the remnant montane rain forest, which does not invade the grassland. This phenomenon could be related to frequent firing of the grassland, the most common reason for arrested successions after forest conversion to grassland in the tropics. There are, however, patana areas known not to have had fires for many years. There is only one tree species in the adjacent rain forest that invades the grassland. This is a tree rhododendron (Rhododendron zcyfanicum), which propagates from stolons originating from woody tubers beneath the ground. The remaining tree species, mostly late-successional or climax trees, are not adapted for invasion or for pioneering on disturbed surfaces. It is therefore possible that species replacing each other over time may become ineffective through too much habitat fragmentation (i.e., their normal dispersal range becomes disrupted). When this happens, the natural processes leading to self-repair of developed landscapes may not function anymore. This would amount to losses of the free services obtained from natural vegetation processes. Costly reforestation or revegetation programs then will have to take their place. Natural areas in developed landscapes also may serve as monitoring sites for industrial pollutants and other forms of environmental degradation. Such natural habitats can serve as biological indicators or benchmark sites for periodic reevaluation of the environmental management of the developed landscape. This function would aid in setting guidelines for standards of environmental quality. This kind of monitoring activity is now built into the use concept of the world biosphere reserves that are promoted through the Man and the Biosphere Program of UNESCO (1974). There is no reason why environmental monitofing, however, cannot be applied to any other natural area, which is not part of the world network. In fact, natural area monitoring is likely to become an important function of any natural area in the future, for
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Natural Systems for develop men^
both maintenance and management of their importance as ecological reserves and their function as biological controls.
ARWSFOR RECREATIOW ROLEOF NATURAL In cultivated landscapes. remaining natural areas are valued as symbols of a natural heritage. As such they serve valuable functions in recreation and education. They are just as important as treasured works of civilized peoples (churches and temples, monuments, sculptures, and other works of art) and will serve as the biological and environmental treasures of the future. A system of natural areas will be the pride of any country that takes the precaution to provide for this in its development planning process. This is shown by such countries as Costa Rica, Sri Lanka, and several African nations that have recognized this value. Their natural areas have become an important item in development efforts. As an added benefit, foreign currency is flowing into these countries, since their natural areas attract interested tourists from more industrialized nations. Sri Lanka, for example, has sponsored much natural area research to improve the management of its national parks, species reserves, and wildlife sanctuaries. A national park and wildlife service is maintained to guard and manage these ecological reserves. Tourists from foreign countries, however, only provide a fraction of the visitors. Most visitors are nationals who treasure these areas for recreational purposes and as symbols of their national heritage. In Sri Lanka, for example, this valuation has deep cultural and religious roots. Of course, public recreation may require its own spectrum of areas and facilities, such as amusement parks, sports arenas, green belts and city parks, botanical gardens, zoos, and natural areas. But natural areas serve a function different from other recreational facilities. Natural areas allow for the socalled remote experiences. People can experience nature away from public concentration or congestion. Natural areas need not support spectacular animals such as elephants or tigers. They only need to contain representative samples of the biological communities of a country or region. Any developing country that will preserve such areas into the future will be greatly enriched.
Natural areas should be considered important resources of knowledge, akin to libraries. In libraries, knowledge is stored in books and magazines, where it can be retrieved by the interested user. The user may have a certain idea of what to look for, but when he goes into the library he may discover totally new relationships that may not have been part of the knowledge of the original
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whose works he has read. Tbe same applies to a natural area researcher. He may be a geologist, soil scientist, botanist, plant pathologist, or entomologist. The* are but a few of the many specialists who can and will make use of natural areas wherever they exist. Their derived knowledge, when published or otherwise communicated through instruction, may be immediately applicable to problems relating to the management and maintenance of natural areas. This knowlege may serve agricultural purposes d i r e d y o r indirectly (as discussed previously); it may serve medical and genetics research or answer fundamental questions of ecological processes. For scientific researchers, natural areas-even small and seemingly unimportant ones-are like a storehouse of books, which only have to be opened and read. Each specialist carries a key. This key is based on his own training and education. to which natural areas have so vastly contributed. For the sake of humanity, one can hope that they will continue to do so.
REDUCING SPECIES LOSS THROUGH HABITAT CONSERVATION
It is important to conserve wild species and their habitats, but the question arises as to what the planner can do about it. His conservation task reduces to three important steps: 1. The planner should insure that the development area is first evaluated
on an ecological basis. 2. Following land evaluation, the planner should institute a zoning scheme, with use categories that include a conservation district. 3. As an extension of the zoning scheme, the planner should then suggest ways to use and protect natural areas within the conservation district. Land evaluation on an ecological basis requires a survey of the existing ecosystems. The aim is to assess the long-term capability of the area for sustained uses and benefits. Instituting a zoning scheme implies a simple delineation of land segments 'into such units as urban areas, agricultural or rural districts, and conservation districts. These are already more-or-less indicated by physiography and present land-use ptterns. Further subdivision within each zone may become advisable. Subdivisions in the conservation district may involve watersheds, indigenous timber reserves, national parks or smaller state parks, and ecological reserves. All such areas may serve as natural or near-natural areas, with differing degrees of protection and policies for use by the people.
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N u u d Systems for Development
Knowledge of conservation district lands bccomes desirable for setting up policies with differing degrees of use and for maintenance management. It is important first, however, to set aside conservation districts or natural areas in the development procea. The more detailed survey of their biological species and the other environmental features they contain can come at a later date. Moreover, this detailed caretaking is not necessarily a task of the planner. T h e planner often must delegate such authority to other professionals, depending on the size and human resources of a developing country. The conservation responsibility of the planner, as outlined here in three steps, is burdened with many complexities. One of these comes through the technical nature of the development process itself. Another relates to the socioeconomic pressures that are exerted on the planner. It takes a highly motivated and well-educated professional to maintain the conservation goals suggested here. The planner easily can become overburdened with requests. He and the scientist, whose responsibility it is to share his knowledge, carry the key responsibilities for conservation planning.
Development is a continuing aim of humanity. Whether consciously or not, improvement of the human condition (development) has always been and will continue to be an overriding god. A human population living in misery may be the result of stagnated or overextended development. Stagnated development may arise for a number of reasons. One important reason is poor use of resources or a scarcity of resources in relation to the carrying capacity of an area. It is known that overextending the carrying capacity through accelerated population growth is one major source of human misery. Overextended or too rapid development can lead to despair. It also may lead to severe unrest or revolutions. Normal, appropriate or organic development is based on satisfying material needs first so that a population becomes free to put its energies into cub tural and social values, including education, the arts, and religion. Development usually proceeds in three steps: access roads, settlers, and conversion of habitats. At first, habitat conversion usually results in an enhancement of human environments. No one can expect human beings to live adequately in totally unmodified environments, but the degree and kind of habitat conversion or environmental modification matters. Accelerated habitat conversion and lateral expansion without any precaution for saving natural habitats and green space inevitably will lead to degradation and destruction. Rapidly changing human environments can take two extreme directions that will lead to destruction.
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fim extreme, habitat conversion is simply the result of human popu-
htbnpeuurc and involves no planning. At the other extreme, planning is involvd, but it is the kind of planning that only focuses on what is technologically possible. ~t is now technologically possible to cut down mountains and to fill in s w m p and valleys. The key instrument in this new technology is the bulldozer. In the hands of man, it can be a destroyer of resources or it can & a blessing for its own technological merits. If the bulldozer is used cautiously and with regard for local ecosystems, it can be used advantageously for changing human environments. The bulldozer and its associated technology were developed in industrialized countries of the temperate zone. Transferred into the tropics without any critical assessment, this bulldozer technology has become an alien force choking out other more gradually evolving indigenous technologies. It appears the only effective way to counterbalance the persuasive import of foreign technology is for the planner to set demands. These demands should include requirements for ecosystem knowledge, which should be delivered or paid for by the technology exporter. A specific demand might be to supply a proper ecologically based land evaluation prior to giving the permit for a specific development project. Or, with logging concessions, the government planner and his department may rightfully insist that the forest be screened for special products, such as those discussed in the section on "Importance of Wild Species and Habitats: Examples." Such screening should be done consecutively with timber surveys and before timber removal so that species containing valuable products can still be propagated in the future. One most important requirement of the developer should be to leave certain areas undeveloped. HOWone might formulate this requirement will be discussed below in the sections on "Land Zoning and Use Restrictions" and "Conservation Land and Natural Area Inventories. " Such demands for important conservation measures may seem unrealistic in countries where timber is the only truly marketable item from natural areas. If a concessionaire does not want a forest with these additional costs, the unexploited forest can then be seen as an investment. Eventually the request for exploitation will be made again. The development planner in a tropical country today is in a powerful bargaining position, provided he is given the necessary authority by his government. Figure 1.2 summarizes the main points.
The planner is exposed to pressures of a different nature than is a scientist. Scientists derive knowledge in their areas of expertise and communicate this
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Natural Systems for DRrelopmcnt
T I Settlers come
Habitat conversion
Planning with bulldozer technology
Habitat degradation and/or destruction
Habitat enhancement
Habitat degradation and/or destruction
Figure 1.2. Directions of development showing three generalized pathways. T h e planner's role should stan at the top. but it often begins only at the third level down or not at all (left-side outcome). Today the planner's greatest challenge is at the fourth level, to move the development process from the "Bulldozer Technology Only" to "Planning with Good Conservation Policies." Only this development direction will achieve habitat enhancements that will outweigh the losses.
knowledge as effectively and frequently as possible. The reward and recognition comes from how well scientists derive knowledge and communicate it. In contrast, the rewards of planners come from how well they guide the development process. It must be extremely tempting for a planner in a position of authority to invite modem bulldozer technology and to encourage rapid progress. Greater immediate rewards can be expected. The larger the area under development, the greater the degree of habitat conversion and the more rapid the hoped-for progress.
m e planner is uked to .ccept leas acclaim for immediate progreaa, to pros.
d cautioudy, and to match bulldozer technology with scientific input for c o n r r v a t i ~ nmanagement. This is an added pressure, but scientists can stand rnady to share the burden aa much as possible. The planner and the scientist the only professionals who can guard against adverse development. Perhaps the main pressures confronting the planner are from the developer and the people. The developer may be a government agency, businessman. contractor, multinational corporation, international financial assistance agency, or development bank. Little ecosystem knowledge can be expected from the developer. The developer may or may not come to the planner directly. More often, the developer may approach the planning ofice with the sanction and full support of the highest level of g o v e r n ~ e n t Since . the planner is a government offrcial himself, this may either facilitate his task or it may make it much more difficult. In any case, what scientists are asking of the planner is not only to review the developer's project proposal but also to identify his motives. Certainly his motives are, first of all, business economics. The big motivational questions are: Who is to become the prime beneficiary of the proposed project, and who will pay the costs? The answers to these questions cannot be obtained entirely from looking through the project proposal or from talking to the developer or the politicians supporting him. At this point, the planner should identify the people who are most directly affected by the proposed development project. As a rule, the people will not come to the planner, unless a proposed development project arouses them to become organized. Therefore, the planner must go to the people and explain to them the proposed project in all details. This can take the form of a properly advertised public hearing or direct contact with local leaders. Unfortunately, this vital step is omitted from the planning process all too often. There may be reasons for omitting the step of talking to the people affected by the proposed development project. Since most of them are political reasons, it should be the politicians' task to represent the wishes of the people. If this is true, then the planner may see no reason for speaking to the involved people himself. This, however, would be a serious mistake. The politician is not a professional with the training and education of the planner and often is in office for only a short term. H e may or may not care very much about the long-term consequences of a particular development project. The planner ideally should be appointed for his professional qualifications and integrity, and his appointment should be a nonpolitical one. Unfortunately, planners often are political appointees, and this has not been always conducive for implementing development projects with long-term sustainability. However, this must become the goal. Planners must establish direct contact with the people and know the peoples' customs and life aspirations. A planner must be an educated professional with a strong compassion for the
Natural Systems for Development
aspirations end needs
Figure 1.3. The pressure cross that either facilitates or complicates the professional task of the planner. The bolder arrows indicate where the greater pressure comes from during the project planning phase. people of the country he is serving. Ideally, he should have deep roots in the history of that country. Figure 1.3 summarizes the pressures that impinge on the task of the planner. Once the project implications are properly communicated to the people and they have given their reaction, the next task is to carry out a proper land assessment of the project area.
It is not necessary that bulldozer technology be matched with the latest in scientific technology, such as computers and satellite imagery. What is necessary is a matching of bulldozer technology with a sound scientific inquiry. In fact, simple methods of land assessment arc preferable to complicated ones that often are too expensive, time consuming, and tend to get bogged down. This does not mean that computers and satellite imagery may not be useful. O n the contrary, where available, these new tools should be used. Although elegance is not required, a quick-and-dirty method is not satisfactory either. The special situation of the humid tropics must be taken fully into account. Simplicity in procedure should be a goal, but there should be no
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of ecological roundness. The whole purpose is to determine the i ~ capability t of the land to suppo* h e project's objectives on a susb e d basis and without incumng inappropriate losses. Such a procedure was recently developed through the East-West Center in Hawaii. A group of land assessment experts and managers from land resource departments and universities of various tropical countries came together in a thrte-wak workshop for this purpose. The full workshop pramduns and all major viewpoints expressed during the workshop w e n published in the proceedings of the conference (Carpenter 1981). It became clear that ecologically sound land assessment procedures must emphasize not only soil and topographic surveys and mapping but also must be directed toward an understanding of the total ecosystems or landscape units of the area. These procedures include coordinated surveys and mapping of all major ecosystem components such as the climate, geological substrate, hydrology, physiography and landforms, topography and soils, current land use, and vegetation covers. It also became apparent that these ecosystem components need evaluation at different levels of detail for different purposes. Two general purposes were defined in relation to administrative objectives and mapping scale. One deals with land capability assessment at an overview level, the other with the same at a detailed level. The overview level refers to a land capability assessment that can be displayed on maps showing a whole state, province, or government district on a single map sheet, approximately the size of an administrator's desk. Scales may vary from 1:100,000 to 1 :1 million (on the latter, 1 cm on the map represents 10 km in the field). The detailed level refers to a land capability assessment that should serve a more specialized land manager; for example, one who is in charge of a regional forestry operation, or one who is in charge of agricultural operations. including perhaps rangelands. In other words, the detailed level land assessment should serve for the land management tasks that are normally assigned to various land departments overseeing the different major land uses of a country. The detailed level inventories of ecosystem components should produce maps that vary in scale from about 1:5,000 to 1:50,000. O n the latter, 1 cm on the map represents 500 m in the field. A summary procedure for each land capability assessment level is attached to this chapter as Appendix 1.A and Appendix 1.B, respectively. These summary procedures and techniques are written as guidelines for the land evaluator (a specialist with training in ecology, soils, and related subjects) and are not meant to be a work outline for the planner. The planner should be aware that such techniques and procedures are available. H e should contract this work to a specialist with funds obtained from the developer and earmarked for this task.
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Na~uralSyrc~mrfor
Development
Based on the overview survey of land capability, it will now be appropriate for the planner, in consultation with his land evaluator, to devise a simple zoning scheme. As mentioned previously, such a zoning scheme may be a simple classification into urban. agricultural, and conservation zones. The main objective of this chapter is to emphasize that designation of a conservation zone or district should be part of any planner's design for land use in his region of responsibility. T h e conservation district should contain the entire spectrum of natural ecosystem variation of an area. For example, in a mountainous region, mountain and valley ecosystems should be included and appropriately protected. If bogs and swamps are a natural p a n of the landscape, such ecosystem types should be included and be appropriately protected. If the area extends to the coast, then coastal ecosystems, such as beaches, mangroves, coastal marshes, lagoons, and reefs should be included in the conservation district. It is not advocated here that the entire region be a conservation district. Urban and agricultural districts have their places too, since without them there is no real development. But these should appropriately occupy a more restricted spectrum of the natural ecosystem; that is, agricultural zones should be located on the arable, more fertile soils, and urban areas away from swamps and not on the best agricultural land. In terms of total area, the conservation district should extend, in various forms and degrees of management, over at feast 50 percent (approximately) of the land surface of the developed area. In the humid tropics, where yearround rainfall is high, the amount of area under tree cover should be much greater. Trees are the most important natural plant cover because they are able to keep humid tropical landscapes from losing fertility in spite of the heavy leaching forces of high rainfall combined with high temperatures year round. For this reason, trees should always remain the dominant component in the landscape. Trees and tree groves also should be saved or cultivated in the a g r i c u l t u r ~and urban zones of the humid tropics. This is best done by leaving intact indigenous forest remnants, even small patches and strips betwee.n agricultural crop fields or as interspersed protective cover between or on the crop fields. In urban areas, forest remnants should be saved and managed as parks. The conservation district, on the other hand, also should be for use by the people, although in a more restrictive sense. Its primary purpose should be that of a species reserve and a reserve where the natural processes involving species interactions and natural habitat are allowed to continue without dominant interference by human beings. Following a detailed land evaluation specially adapted to the conservation
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prcscott-Allen, C . , and R. Prescott-Allen. 1982. Economic Contributionr of Wild Plants and Animals to & d o p i n g Countries. Report prepared for U.S. AID/ MAB Program. Raven, P. H.1981. Tropical rain forests: A global responsibility. Natural Hislory 90(2):29-32. steenis-Kruseman, M . J. van. 1953. Select Indonesian medicinal plants. Bull. Uganis. Sci. Res. 18:1-90. Synge, H. 1980. The Biological Aspects of Rare Plant C o m a t i o n . New York: John Wiley and Sons. UNESCO. 1973. Intmational Classifiation and Mapping of Vegetation. Ecology and Conservation Series No. 6. Paris: UNESCO. Walter, H., E. Harnickell, and D. Mueller-Dombois. 1975. Climate-Diagram Maps of the Individual Continents and the Ecological Climatic Regions of the Earth. New York: Springer Verlag. Webb, L. J., J . G . Tracy, and W. T . Williams. 1976. The value of structural features in foresty typology. Austr. J. Ecol. 1:3-28. Whitmore. T. C . 1980. Potentially economic species of Southeast Asia forests. Biolndonesia 7:65-74.
