92 • Technologies To Maintain Biological Diversity 



Table 4-2.— Management Systems and Conservation Objectives 



Onsite 



Offsite 



Ecosystem maintenance 



Species maintenance 



Maintain: 



• a reservoir or "library" of 

 genetic resources 



• evolutionary potential 



• functioning of various 

 ecological processes 



• vast majority of known 

 and unknown species 



representatives of unique 

 natural ecosystems 



Maintain: 



• genetic interaction be- 

 tween semidomesticated 

 species and wild relatives 



• wild populations for sus- 

 tainable exploitation 



• viable populations of 

 tfireatened species 



• species thiat provide im- 

 portant indirect benefits 

 (for pollination or pest 

 control) 



• "keystone" species with 

 important ecosystem sup- 

 port or regulating function 



Living collections 



Germplasm storage 



Maintain: 



• breeding material that can- 

 not be stored in 

 genebanks 



• field research and develop- 

 ment on new varieties and 

 breeds 



• offsite cultivation and 

 propagation 



• captive breeding stock of 

 populations threatened in 

 the wild 



• ready access to wild spe- 

 cies for research, educa- 

 tion, and display 



Maintain: 



• convenient source of 

 germplasm for breeding 

 programs 



• collections of germplasm 

 from uncertain or threat- 

 ened sources 



• reference or type collections 

 as standard for research 

 and patenting purposes 



• access to germplasm from 

 wide geographic areas 



genetic materials from criti- 

 cally endangered species 



SOURCE: Office of Tecfinology Assessment, 1986. 



to collect an endangered species or germplasm 

 and maintain it outside the country to ensure 

 survival and to facilitate access. 



The applicable management systems and 

 technologies also depend largely on economic 

 factors. Costs of alternative management sys- 

 tems and the value of resources to be conserved 

 may be relatively clear in the case of genetic 

 diversity. For example, the benefits of breed- 

 ing programs compared with the cost of seed 



maintenance easily justify germplasm storage 

 technologies (see ch. 7). However, cost-benefit 

 analysis is more difficult when benefits are dif- 

 fuse and accrue over a long period (7). This 

 problem is particularly acute for onsite main- 

 tenance programs where competition for land 

 exists. Current threats to biologically rich trop- 

 ical forests by land seeking peasant agricul- 

 turalists illustrate these conflicting interests. 



COMPLEMENTARINESS OF MANAGEMENT SYSTEMS 



Each of the four management systems serves 

 different objectives. Historically, the two off- 

 site approaches have developed independently 

 from onsite approaches. However, some links 

 have developed between the different manage- 

 ment programs (see figure 4-1]. Improvement 

 of such links will contribute substantially to the 

 cost-effectiveness of each management system 

 and will help to achieve the overall goal of main- 

 taining biological diversity. 



Biological Linkages 



Transfers of biotic material among the four 

 management systems can enhance diversity. 



Exchanges between onsite systems occur, for 

 example, when genetic material from wild 

 plants becomes incorporated into locally cul- 

 tivated varieties. Exchanges between offsite sys- 

 tems occur, for example, when seeds and clones 

 of agricultural varieties are taken from storage 

 and grown out in living collections for use in 

 breeding programs. Similarly, a zoo may col- 

 lect animal semen from its living collection and 

 place it in cryogenic storage to expand the num- 

 ber of individuals it can maintain — in a sense 

 creating a "frozen zoo." 



Exchanges of species or germplasm between 

 wild areas and living collections are most evi- 

 dent when wild specimens are taken for zoos. 



