44 • Technologies To Maintain Biological Diversity 



Serengeti National Park (Tanzania] and Wind 

 Cave National Park (South Dakota) provide re- 

 search significant for range management. Re- 

 search includes, for example, studies of the ex- 

 tent to which grazing intensity increases 

 primary production and the protein content and 

 digestibility of grasses (28). Research on spe- 

 cies and natural gene pools also requires eco- 

 system maintenance. 



Representative examples of major ecosystems 

 are used as reference sites for baseline moni- 

 toring on productivity, regeneration, and adap- 

 tation to environmental change. In addition, 

 evaluation of development projects to ensure 

 they are both economical and sustainable calls 

 for assessment of, among other things, their 

 environmental effects measured against un- 

 altered sites w^ith similar vegetation, soils, and 

 climate. 



The Zambezi Teak Forest ecosystem, for ex- 

 ample, which yields Zambia's most valuable 

 timber, is declining rapidly, due to excessive 

 logging, fire, and shifting cultivation. If present 

 trends continue, this forest would effectively 

 disappear in 50 years. Attempts at artificial 

 regeneration have met with little success. To 

 improve understanding of natural regeneration, 

 an undisturbed tract of the forest in Kafue Na- 

 tional Park is being studied. Continued moni- 

 toring of the Kafue tract will provide data 

 needed for assessing costs and benefits of any 

 silviculture system for the Zambezi Teak For- 

 est (72,74). 



Ecosystems are also living classrooms. The 

 University of California's Natural Land and 

 Water Reserves System includes 26 reserves 

 representing 106 of the 1 78 habitat types iden- 

 tified for the State. The reserves are used for 

 instruction and research in botany, geology, 

 ecology, archeology, ethology, paleontology, 

 wildlife management, genetics, zoology, pop- 

 ulation biology, and entomology (52). Enabling 

 children and adults to experience different eco- 

 systems is an effective way to teach ecological 

 processes, genetic variation, community com- 

 position and dynamics, and human relations 

 with the natural world. 



Species Diversity 



Species diversity is the basis for many fields 

 of scientific research and education. The ar- 

 ray of invertebrates used in research illustrates 

 the importance of diversity to the advancement 

 of science. The 100 or so species of Hawaiian 

 picture-winged fruit flies are the organisms of 

 choice for basic research on genetics, evolu- 

 tionary biology, and medicine. Tree snails of 

 Hawaii and the Society Islands provide ideal 

 material for research on evolution and genetic 

 variation and differentiation (57). 



Bristlecone pines, the oldest known living 

 organisms and found only in the U.S. South- 

 west, are used to calibrate radiocarbon dates 

 and hence, are important for archeology, pre- 

 history, and climatology (62). Contributions of 

 plant and animal species to biomedical research 

 and drug synthesis abound (63,71). Examples 

 include: 



• Desert pupfishes, found only in the South- 

 west, tolerate salinity twice that of salt- 

 water and are valuable models for research 

 on human kidney disease (63). 



• Sea urchin eggs are used extensively in ex- 

 perimental embryology, in studies of cell 

 structure and fertilization, and in tests on 

 the teratological effects of drugs (98). 



• Medicinal leeches are important in neu- 

 rophysiology and research on blood clot- 

 ting (98). 



• An extract of horseshoe crabs provides the 

 quickest and most sensitive test of vaccines 

 and intravenous fluids for contamination 

 with bacterial endotoxins (98). 



• Butterfly species are used in research on 

 cancers, anemias, and viral diseases (82). 



• The study of sponges is making substan- 

 tial contributions to structural chemistry, 

 pharmaceutical chemistry, and develop- 

 mental biology and has also resulted in the 

 discovery of novel chemical compounds 

 and activities. D-arabinosyl cytosine, an im- 

 portant synthetic antiviral agent, owes its 

 development to the discovery of spongouri- 

 dine, which was isolated from a Jamaican 



