228 • Technologies To Maintain Biological Diversity 



Private holdings also contribute to maintain- 

 ing diversity, especially through the protection 

 of remnant areas. Many of the remaining tall 

 grass prairies in the Midwest, for example, are 

 privately owned by individuals or as railroad 

 right-of-ways. Private land trusts lease parcels 

 of land for biological or historical significance, 

 which may contribute to onsite diversity main- 

 tenance. (For further details, see ref. 55.) Many 

 of the land parcels are small and isolated, with 

 little attention given expressly to diversity main- 

 tenance, but they do contribute to the patch- 

 work of natural areas in the United States. An 

 assessment of the protection associated with 

 all these Federal, State, local, and private land 

 designations is under way (11]. 



One private institution with an explicit goal 

 of natural area preservation is The Nature Con- 

 servancy (TNC). TNC is a nonprofit organiza- 

 tion with chapters in most States. Its objectives 

 are to identify species and community diver- 

 sity onsite, purchase areas or work with land- 

 holders to protect the species or community, 

 and manage areas to ensure the continued ex- 

 istence of the species or community. 



TNC, through State Natural Heritage Pro- 

 grams (discussed in ch. 5 and in the next sec- 

 tion], conducts field investigations of rare, 

 threatened, or endangered organisms and com- 

 munities across the Nation. The information 

 generated from these surveys helps identify 

 organisms that should be given Federal or State 

 protected status, as well as habitats and com- 

 munities where special attention is necessary. 



TNC, one of the largest private landholders 

 in the United States, owns 895 preserves (39]. 

 In addition, it works with Federal, State, and 

 local governments to designate protected areas. 

 Thus, the organization, through a grassroots 

 approach, is effectively identifying and main- 

 taining a diversity of rare species or commu- 

 nity types in the United States. 



Species Habil 



The most comprehensive national program 

 for the protection of species diversity and their 

 habitats is the Endangered Species Program, 



authorized under the Endangered Species Act 

 of 1973. The program authorizes the Secretary 

 of the Interior, through the U.S. Fish and Wild- 

 life Service (FWS], and the Secretary of d 

 Commerce, through the National Marine Fish- •> 

 eries Service (NMFS), to protect endangered 

 and threatened species of plants and animals 

 in the United States and elsewhere. 



The program, administered by the Office of 

 Endangered Species, has several phases: list- 

 ing species, developing recovery plans, and 

 managing species' habitats. Species are listed 

 as threatened or endangered when sufficient 

 information on the status and distribution of 

 the species suggests significant declines in pop- 

 ulation or range or both and when an extensive 

 public review has been completed. In general, 

 a species is considered a candidate between the 

 time a petition to propose a species is received 

 and the listing process is completed. In addi- 

 tion, many candidate lists are put together 

 through expert review by the regional and 

 Washington offices of the FWS. 



Lists of candidates are published periodically 

 in the Federal Register. (The most recent lists 

 were published in September 1985 for verte- 

 brates and plants and in May 1984 for inver- 

 tebrates.] To date, approximately 3,900 species 

 and subspecies of plants, vertebrates, and in- 

 vertebrates are candidates compared with ap- 

 proximately 385 species already listed (18). 



When a species is listed, the next step is de- 

 velopment of a formal recovery plan outlining 

 the responsibilities of all parties with jurisdic- 

 tion over the species' habitat and their man- 

 agement roles. Recovery plans are advisory doc- 

 uments to the Secretary of the Interior, not 

 binding agreements. Recovery plans are ap- 

 proved or awaiting approval for approximately 

 two-thirds of the species listed (see table 9-3]. 

 Implementation of recovery activities, however, 

 has been slow (13]. 



The thrust of the Endangered Species Pro- 

 gram is protection through proper management 

 of a species' habitat. Most management activi- 

 ties are carried out by Federal and State agen- 

 cies with jurisdiction over the habitats, not by 

 FWS (unless the species occur on National 



