Ch. 2— Importance of Biological Diversity • 49 



Ecosystem diversity is a significant recrea- 

 tional asset in developing countries as vi^ell. In 

 Venezuela, the mangrove forests of Morrocoy 

 National Park attract 250,000 to 500,000 visi- 

 tors per year (39); in Nepal, mountain land- 

 scapes, rhododendron forests, and fauna bring 

 in foreign exchange (55). 



Species Diversity 



About 95 million Americans a year partici- 

 pate in nonconsumptive recreational uses of 

 wildlife (observing, feeding, or photographing 

 wild plants and animals); each year 54 million 

 Americans fish and 19 million Americans hunt 

 for sport. In the process they spend $32.4 bil- 

 lion per year (95). 



Surveys of American recreational uses of 

 wildlife reveal that a number of different spe- 

 cies interest people. Recreational hunters in 

 North America pursue some 90 species (73,74). 

 Millions of Americans take time to observe not 

 only birds and mammals, but also amphibians, 

 reptiles, butterflies, spiders, beetles, and other 

 arthropods (95). 



Little data exist on wildlife recreational use 

 by people in developing countries, but for sev- 

 eral nations wildlife-based tourism is big busi- 

 ness. The spectacular wild animals of east and 

 southern Africa are the resource base of a tour- 

 ist industry that brings millions of dollars in 

 foreign exchange. In 1985, Kenya netted about 

 $300 million from almost 500,000 visitors, mak- 

 ing wildlife tourism the country's biggest earner 

 of foreign exchange (1). 



Genetic Diversity 



Millions of home gardeners and members of 

 horticultural and animal breed associations de- 

 rive recreational benefit from genetic diversity. 

 So, too, do millions of anglers who take advan- 

 tage of stocking and enhancement programs. 

 Tourism associated with genetic diversity in- 

 volves fewer people, although the Rare Breeds 

 Survival Trust in the United Kingdom receives 

 100,000 visitors a year. In North America, at 

 least 10 million people visit the some 200 liv- 

 ing historical farms — open-air museums that re- 

 create and interpret agricultural and other 

 activities of a particular point in history (91). 



BENiFITS TO AGRICULTURE AND HARVESTED RESOURCES 



In agriculture, a diversity of ecosystems, spe- 

 cies, and genetic material provides increased 

 amounts and quality of yields. In a world where 

 population is rapidly increasing, assuring a con- 

 tinued increase in harvested resources is es- 

 sential. Diversity in an agroecosystem provides 

 habitat for predators of crop pests and breed- 

 ing sites for pollinators. Diversity of species can 

 be a buffer against economic failure and can 

 also play an important role in pest management. 

 Further, the use of genetic materials by breed- 

 ers has attributed to at least 50 percent of the 

 increase in agriculture yields and quality. 



Ecosystem Diversity 



Both diversity and isolation affect the ability 

 of pests to invade a crop. They also affect the 

 supply of pests' enemies. Uncultivated habitats 

 next to croplands contain wildflowers, which 



contain important nutrients for the adult stages 

 of predatory and parasitic insects (37). Wild- 

 flowers also support essential alternate hosts 

 for parasites, especially in seasons when pests 

 they prey on are not present. In California, for 

 instance, wild brambles [Rubus) provide an off- 

 season reservoir of prey for wasps, which con- 

 trol a major grape pest. This arrangement saves 

 grape growers $40 to $60 per acre in reduced 

 pesticide costs (6,54). 



A variety of wild habitats also provides food, 

 cover, and breeding sites for pollinators. Wild 

 pollinators (chiefly insects) make major contri- 

 butions to the production of at least 34 crops 

 grown or imported by the United States, with 

 a combined annual average value of more than 

 $1 billion. They are the main pollinating agents 

 in the production of cranberry and cacao, the 

 propagation of red clover, and the production 



