Ch. 9— Maintaining Biological Diversity in the United States • 227 



Photo credit: National Par/t Service 



Hearts Content Scenic Area National Natural Landmark, 

 part of ttie U.S. Forest Sen/ice's Allegheny National 

 Forest, protects a rare example of virgin, old-growth 

 forest dominated by white pines of up to 400 years old. 



ance maintenance of diversity with recreation 

 opportunities. In some cases, these goals con- 

 flict, as they have with managing the grizzly 

 bears at Glacier National Park. 



Contributions of these Federal programs to 

 maintaining diversity depends on the degree 

 of protection offered for each designation (10). 

 For example. National Natural Landmarks are 

 designated to identify and conserve unique, 

 rare, or representative communities in the 

 United States. Designation of these sites does 

 not, however, include protecting the site from 

 human alteration. Approximately half the Na- 

 tional Natural Landmarks exist on private 

 lands, where conservation depends on the good 



will of the individual landowner. National Nat- 

 ural Landmarks on Federal- or State-controlled 

 lands require the cooperation of the authorized 

 agency to ensure that protection is considered 

 in the area's management. 



An attempt has been made to identify the 

 amount of potential ecosystem diversity that 

 is protected in Federal landholdings. Potential 

 ecosystem diversity is that which would be ex- 

 pected to develop on a site under natural con- 

 ditions. According to an assessment that con- 

 sidered areas of approximately 23,000 acres or 

 larger, lands of four agencies failed to include 

 22 percent of the recognized ecosystem types 

 (i.e., 69 out of 315). These four agencies were 

 the National Park Service, Forest Service, Fish 

 and Wildlife Service, and Bureau of Land Man- 

 agement. Another 29 percent of these ecosys- 

 tem types were only minimally included (9). 

 Since this analysis assessed only potential diver- 

 sity, it probably underestimates existing eco- 

 system diversity in the landholdings (9). The 

 largest number of unrepresented types were in 

 Texas and Oklahoma, which have relatively 

 large amounts of ecosystem diversity but rela- 

 tively few Federal lands. 



Another analysis of the same Federal hold- 

 ings, using a different classification scheme for 

 potential ecosystem diversity, obtained simi- 

 lar results (12). These two studies indicate that 

 any attempt to include all ecosystem types 

 within Federal programs would require con- 

 siderable expansion of existing holdings. For 

 the national wilderness preservation system, 

 however, almost half the unrepresented types 

 in that system could be added from existing 

 Federal agency holdings (12). 



Natural area management programs also oc- 

 cur at the State level. State parks, forests, and 

 protected sites may be managed for one or a 

 few resources, but they help preserve some rem- 

 nants of diversity, particularly when they are 

 managed in conjunction with private or Fed- 

 eral reserves. State designations could also be 

 wildlife areas, fishing areas, university research 

 stations, botanic sites, school and other public 

 lands, or special districts (e.g., a water man- 

 agement district) (10). 



