Chapter 5 



Maintaining Biological Diversity Onsite 



HIGHLIGHTS 



Maintaining plant, animal, and microbial diversity in their natural environ- 

 ment (onsite] is the most effective way to conserve maximum biological diver- 

 sity over the long term. 



Strategies to maintain diversity onsite have evolved from strict preservation 

 to multiple use. More recently, attention is being given to integrating conser- 

 vation with development in areas outside protected zones. 

 Guidelines for optimum biological design of protected areas are improving. 

 But decisions on design are determined more often by socioeconomic and po- 

 litical factors than by scientific principles. 



Techniques for restoring diversity on degraded sites are being improved as 

 knowledge of natural plant and animal succession increases. However, com- 

 plete restoration is often not feasible, and partial restoration is usually slow 

 and expensive. 



Opportunities for improving national and global conservation of diversity onsite 

 include 1) promoting an ecosystem approach to protected area establishment 

 and management, 2) encouraging innovative resource development methods 

 that treat conservation as a form of development, 3) supporting multidiscipli- 

 nary research on the many factors to consider when designing nature reserves, 

 and 4) developing training and job opportunities for experts in all these areas. 



INTRODUCTION 



Plants and animals can be maintained where 

 they are found, that is, onsite, either by pro- 

 tecting certain sites from change or by manag- 

 ing change to support some portion of the nat- 

 ural biota. Most biological diversity can only 

 be maintained in a natural condition for three 

 reasons: 



1. For most species, technologies have not 

 been developed to keep substantial num- 

 bers of individuals alive outside their nat- 

 ural environments. 



2. For species that can be kept alive in artifi- 

 cial conditions, preserving genetic diver- 

 sity usually entails maintaining numerous 

 individuals from genetically distinct pop- 

 ulations. Such preservation is financially 

 and logistically feasible for only a few of 



the hundreds or thousands of species of 

 many ecosystems. 



3. Species survive gradual changes in their 

 natural environments by continuous evo- 

 lution and adaptation — processes that are 

 arrested in offsite collections. 



Strategies for maintaining biological diver- 

 sity onsite range from single-species manage- 

 ment to protection of complete ecosystems in 

 designated natural areas. The various ap- 

 proaches are complementary. For example, a 

 European nature reserve system established 

 with broad conservation objectives contains 

 some 10,000 sites of plant species that also are 

 useful for breeding and for research into the 

 chemistry of natural substances. 



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