50 • Technologies To Maintain Biological Diversity 



and propagation of cashew and squash. They 

 are also significant pollinators for such crops 

 as coconut, apple, sunflower, and carrot. The 

 abundance of wild pollinators is largely deter- 

 mined by the availability of ecosystem diver- 

 sity (woods, scrub, bare ground, moist areas, 

 patches of flowers) within flight range of the 

 crops to be pollinated (73,74). 



Permanent pastures and rangelands occupy 

 one-fourth of the Earth's land surface (31). Be- 

 cause they support most of the world's 3 bil- 

 lion head of domesticated grazing animals (45), 

 rangelands can be considered harvested eco- 

 systems, where the nutrients and solar energy 

 of marginal lands are converted into meat, milk, 

 wood, and other goods. 



In the United States, 34 rangelands are in- 

 volved and include plains, prairie, mountain 

 grassland, and Texas savanna (93). Pastoral 

 nomadism and migrations by wild herbivores 

 are traditional ways of using these resources. 

 Modern ways include hauling sheep between 

 summer and winter ranges, which may be 300 

 to 400 kilometers apart in the intermountain 

 region (12). 



Species Diversity 



Diversity of harvestable species acts as a 

 buffer that allows people in fluctuating envi- 

 ronments to cope with extremes. For instance, 

 in Botswana, five wild plant species are exten- 

 sively used by pastoralists and river people, but 

 an additional 50 or more species are resorted 

 to in times of drought (17). 



Harvested species provide much of the sub- 

 sistence of indigenous peoples and rural com- 

 munities throughout the world. Wild bearded 

 pig and deer contribute about 36,000 tons of 

 meat a year to rural diets in Sarawak, Malay- 

 sia. This amount of meat from domestic ani- 

 mals would cost about $138 million. (15). Per 

 capita consumption of harvested food by Inuit 

 in the North American Arctic averages annu- 

 ally from 229 kg (504 lb) to 346 kg (761 lb). The 

 per capita cost of buying substitute food (usu- 

 ally of lower nutritional and cultural value) was 

 estimated to be $2,100 per year (1981 figures) 

 (4,101). 



The commercial timber, fishery, and fur in- 

 dustries obtain most of their resources by har- 

 vesting wild species. Harvested resources are 

 also major contributors to the pharmaceutical 

 industry, and to many other industries as well. 

 The average annual value of the wild resources 

 produced and imported by the United States 

 between 1976 and 1980 was about $27.4 billion, 

 of which $23 billion was timber (73,74). 



Many species are involved, but most of them 

 are economically significant only to the trades- 

 men involved. Even so, the number of harvested 

 species might run up to more than a hundred. 

 For example, it takes on average 70 species to 

 make up 90 percent of the annual value of U.S. 

 commercial fishery landings (74). 



In agriculture, two types of diversity are use- 

 ful in pest management programs: crop diver- 

 sity and pest enemy diversity. Crop diversity 

 (multiple cropping) can promote the activity of 

 beneficial insects. For example, to attract 

 Lycosa wolf spiders, the main predators of corn 

 borers in Indonesia, farmers interplant the corn 

 with peanuts (46). In California, lygus bugs, one 

 of the main pests of cotton, are controlled some- 

 what by strip-planting alfalfa, which the bugs 

 prefer to cotton (11). Pest enemy diversity in- 

 cludes introduced as well as native enemies. 

 The Florida citrus industry saves $35 million 

 per year by using three parasitic insect species 

 that were imported and established at a cost 

 of $35,000. Some 200 foreign insect pests in the 

 United States are controlled by introduced par- 

 asites and predators (63). 



A long-standing use of wild species diversity 

 is as a source of new domesticates. In the 

 United States, the combined farm sales and im- 

 port value of domesticated wild species is well 

 over $1 billion per year. The domestication of 

 two major groups of resources— timber trees 

 and aquatic animals— has only begun and is at 

 about the same stage that agricultural domes- 

 tications were some 5,000 years ago. But agri- 

 cultural and horticultural domestications are 

 still occurring. 



Among the successful new food crops devel- 

 oped this century are kiwifruit, highbush blue- 

 berry, and wild rice (most of the wild rice 



