Biodiversity (1988) / Chapter Skim
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Part 9: Alternatives to Destruction
Part 9: Alternatives to Destruction
Pages 353-390
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From page 354... ...
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From page 355... ...
In this volume are a number of analyses of the causes of habitat destruction and the economic realities facing the Third World. Most tropical deforestation, and with it the major threat to biological (diversity, comes from efforts to increase the level of subsistence and to generate foreign exchange for the purchase of goods manufactured in the developed world.
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From page 356... ...
The National Research Council s Board on Science anc! Technology for International Development, on the other hand, has deliberately set out to search for animals that have a high potential for domestication or husbandry (NRC, 19831.
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From page 357... ...
Again on a priori grounds we can predict that there must be many plants that have or are in themselves valuable, undiscovered products. The tropical forests of the world are the most intense battlegrounds for species competition on the face of the Earth.
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From page 358... ...
lanzen s application of his extensive theoretical insights to the practical problems involved in regrowing tropical forests is a shining example to us all (see Chapter 14~. The involvement of several Smithsonian biologists in research on alternatives to destruction is another excellent sign.
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From page 359... ...
Board on Science and Technology for International Development Report 37. National Academy Press, Washington, D.C.
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From page 360... ...
1970. Relationships between fruiting seasons and seed dispersal methods in a neotropical forest.
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From page 361... ...
r ~ , ~ oday, the foundation and health of ag' riculture in industrial countries largely depend on their access to the rich crop genetic diversity found in Third-World countries. Yet the very same germplasm resources most sought after for their potential applications in biotechnology are constantly threatened by the spread of modern agriculture.
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From page 362... ...
Although most traditional agroecosystems are undergoing some process of modemization or drastic modification, conservation of crop genetic resources can still be integrated with agricultural (development, especially in regions where rural development projects preserve the vegetational diversity of traditional agroecosystems and depend upon the peasants rationale to utilize local resources and their intimate knowledge of the environment (Alcom, 1984; Nabhan, 1985; Sarukhan, 1985~. ~Landrace populations consist of mixtures of genetic lines, all of which are reasonably adapted to the region in which they evolved but which differ in reaction to diseases and insect pests.
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From page 363... ...
In a recent article (Altieri and Merrick, 1987) , we suggested the best ways in which traditional varieties, agroecological patterns, and management systems can be integrated into rural development programs to salvage crop genetic resources.
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From page 364... ...
In Thailand, rice farmers plant the modem semidwarf varieties in part of their land cluring the dry season anc] sow traditional varieties during the monsoon season.
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From page 365... ...
In many areas, unfortunately, the return of some peasant communities to native varieties has been difficult because of genetic erosion. Several factors have contributed to this loss of crop genetic resources (Nabhan, 1986~: decrease in the number of growers, decrease in crop size per field, decrease in planting frequency, loss of seed~saving and seed-collection skills, and changes in the crop's vulnerability to pests and weeds.
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From page 366... ...
When valuable crop genetic resources are incorporated into farming systems designed to encourage self-sufficiency of the rural poor, important conservation gains can be achieved. This is illustrated by the efforts by Nabhan (1984)
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THE FUTURE A number of people have stressed the importance of in situ preservation of crop genetic resources but have failed to suggest practical avenues to achieve this goal in ThircI-World countries (Prescott-Allen and Prescott-Allen, 1982~. If the conservation of crop genetic resources is incleec]
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1987. In situ conservation of crop genetic resources through maintenance of traditional farming systems.
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From page 369... ...
1982. The case for in situ conservation of crop genetic resources.
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From page 370... ...
Animal species selected for management projects feed directly on forest vegetation, so there is an incentive to native populations to preserve some of the forest. STRI is using knowledge derived from basic research to explore approaches that will not only yield harvestable products but will also protect natural forest.
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From page 371... ...
to great increases in knowledge of the biology of the green iguana (Burghardt and Rand, 1982~. Formerly a wide-ranging reptile, and prized as a protein source for more than 7,000 years, this animal is now drastically decreasing in numbers clue to habitat destruction from slash-and-bum farming, conversion of forested lands to pasture, increased use of biocides, ant!
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From page 372... ...
However, the annual cattle yield drops to 15 kilograms per hectare after 10 to 15 years because the quality of the pasture is lower. By comparison, the results of the Iguana Management Project indicate that iguanas could provide a sustainable yield of more than 230 kilograms per hectare annually.
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From page 373... ...
Using species that are not traditional in Panama, STRI hopes to restore and maintain soil fertility by selecting and establishing highly adaptable, hardy, and competitive leguminous plant species with emphasis on multipurpose shrubs and trees that can be used for green manure, forage, firewood, and timber production; to evaluate the adaptability of potential
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From page 374... ...
MANAGEMENT OF GAME MA1\IMALS Native populations in the Neotropical humid forests have traditionally relied on native wildlife for their high~quality protein. Since the advent of firearms and headlamps, more efficient hunting methods combined with habitat destruction have resulted in the extermination of game species in many areas.
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From page 375... ...
, they could be cropped as a sustainable yield protein. Most forest game animals are frugivorous, and as a result, they experience high juvenile mortality during seasonal scarcity of fruit (Smythe, 1986~.
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1986. Iguana management in Central America.
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In particular, modern and traditional genetic engineering techniques have been combined with modern agricultural methods and chemical engineering know-how to procluce high-volume biomass feeclstocks at low cost for use as energy, chemicals, anc! building materials.
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Very few things in this world have a global impact on us as great as the forest/ grassland ecosystem. A balanced tree and grass ecosystem controls runoff, supplies water, and supports irrigation, soil fertility, and oxygen production.
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Modern agricultural techniques are combined with our understanding of the tree growth to produce feedstocks that are conveniently handled in conversion processes. One biologically engineered system produces two varieties of wood grass products: the dry Dushen and the wet Dushen (Shen, 1982; Shen et al., 1984~.
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The energy products include heat, electricity, low- ancl medium-Btu gas, pipeline gas, and liquid fuels. The wood grass production system also stabilizes soil a tremendous implication for erosion control and watershed management in many countries.
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~ 8 ) FIGURE 43-1 Feedstock applications of dry and wet Dushen and direct extrusion applications of wood grass.
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From page 382... ...
Second, the limit on the quantity of biomass that can be obtained can be ascertained from a growth curve for any density, provided N is not so low that closure does not take place. The implications of these observations are that the mean annual increment of biomass at harvest can be enhanced by increasing the planting density and that there is an optimal planting density for each rotation (age of trees at harvest)
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From page 383... ...
fir one is concerned about crop flexibility, the initial planting density should be chosen to control the size of the root system as well. Wood grass production involves a degree of management as high as that in land consumption activities such as those found in urban areas or in association with roads, mining, and water impoundments.
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From page 384... ...
Due to (differences in agricultural systems and practices and in topographical and climatic conditions, there are different schemes for producing Dushen feedstock using the wood grass production system. There are also considerations concerning capital versus labor intensity and availability.
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From page 385... ...
The long-term applications include its use as chemical feedstock, which has the highest market value. In China, the regions of most intensive applications are located in the Northeast, where there is need for industrial fuel and heating, in Eastern China, and in Northwestern China.
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From page 386... ...
Furthermore, selected wood grass configurations reduce groundwater runoff, increase groundwater infiltration, and recharge groundwater reservoirs. In designing the wood grass production system, we first applied traditional genetic selection to hybrid trees, which were cloned for a number of attributes.
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From page 387... ...
i ~_~_ groundwater runoff, increase groundwater infiltration, recharge groundwater reservoirs, and produce the by-products of fuelwood and fodder. A typical design of a clonal hedgerow system entails the construction of hillside ditches and the planting of two rows of trees or shrubs on the rise (bund)
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From page 388... ...
This would increase the per-hectare productivity of the CAM [' /l _ i{~% Water Infiltration at Hillside Ditches Shallow Rooted Contour Hedgerows for ' Vegetative Propagation of Planting Stock Deep Rooted Trees which "Pump" Nutrients from Subsoil Strata /./N 1~ . i ~ __, ~ .~ /, /} Interplanted Pasture __ - and Forage Legumes ~ , FIGURE 43-8 Complete biologically engineered system of contour hedgerows.
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1984. Contour hedgerows for soil erosion control and planting stock, forage and fuelwood production in highland regions.
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