National parks 



Research natural areas 



Marine sanctuaries 



Resource development 

 planning 



Agroecosystems 

 Wildlife refuges 

 In-situ genebanks 

 Game parks and reserves 



Zoological parks 

 Botanic gardens 

 Field collections 

 Captive breeding programs 



Seed and pollen banks 

 Semen, ova, and embryo banks 

 Microbial culture collections 

 Tissue culture collections 



Increasing human intervention ■ 

 Increasing natural processes 



SOURCE: Office of Technology Assessment, 1986. 



is to maintain ecosystem diversity. Offsite main- 

 tenance cannot accomplish this objective be- 

 cause many species cannot Uve outside their 

 natural habitats. An ecosystem approach allows 

 processes, such as natural selection, to con- 

 tinue. Survival, for some species, depends on 

 complex interactions with other species in their 

 habitats. Maintaining diverse ecosystems also 

 continues ecological processes, such as nutri- 

 ent cycling, that typically depend on the inter- 

 action of numerous species (5). 



Programs to maintain a diversity of ecosys- 

 tems usually identify different ecosystem types 

 and then attempt to preserve a sample of each 

 type (see ch. 5). Some types, such as cloud 

 forests, are rare and confined to small areas. 

 These are especially vulnerable and receive spe- 

 cial emphasis in some conservation programs. 



The ecosystem approach is used not only for 

 natural areas but also for traditional agricul- 

 tural ecosystems. Pressures to modernize these 

 "agroecosystems" threaten the characteristi- 

 cally high levels of crop and livestock genetic 

 diversity these systems represent— and upon 

 which modern agricultural systems continue 

 to depend. 



Onsite Species Maintenance 



When the objective is to maximize direct ben- 

 efits from diversity, such as production of an 

 optimal mixture of game, fish, timber, and sce- 

 nic values, then the preferred approach is often 

 to manage particular species and their habitats. 

 Managing at the population level is preferred 

 when the objective is to avert extinction of a 

 rare or threatened species or subspecies. 



Because managing all species would be im- 

 possible, biological, political, and economic fac- 

 tors determine which species will receive di- 

 rect attention. Preference is given to species 

 with recognized economic value, for example. 



Noncommercial species that are rare and en- 

 dangered also are given management attention 

 to ensure survival of wild populations. Simi- 

 larly, species that provide important indirect 

 benefits, such as pollination or pest control, 

 may receive attention. Ideally, management 

 should also focus on keystone species, i.e., those 

 with important ecosystem support or regula- 

 tory functions. 



Offsite Maintenance in 

 Living Collections 



Zoological parks, botanic gardens, arbore- 

 tums, and field collections are common homes 

 for living collections. Living collections serve 

 several conservation objectives. Zoos and bo- 

 tanic gardens can propagate species threatened 

 with extinction in the wild, sometimes enabl- 

 ing the repopulation of a newly protected or 

 restored habitat. Arboretums and living collec- 

 tions kept at places like agricultural research 

 stations maintain the genetic diversity of plants 

 not amenable for germplasm storage as well 

 as numerous livestock varieties that are not 

 commercially popular but are culturally signif- 

 icant or are needed for research and breeding 

 programs. 



The number of species maintained in living 

 collections is limited by the size of the facil- 

 ities and the relatively high maintenance cost 



