— Widespread local declines in amphibian populations are raising concerns about 

 the viability of nnany amphibian species. 



The Federal forest and rangelands encompass a large share of natural variety in the 

 United States. However, not all species and communities are represented on the 

 Federal lands, and wide-ranging species will not be viable in the long run if restricted 

 to public lands (fig. 13). Both private and public lands will play vital roles in protecting 

 biological diversity. However, continuing land use intensification and fragmentation, 

 combined with increasing demands for resource outputs are likely to result in further 

 losses of natural variety. 



■» 



X 



^^^^^^^B 



N>* 





j^f. 



M' 



^M 



^ • ■ i- ■ * . T 



XiP« 



•^.''Y^' 



Figure 13 — Wide-ranging species will not be viable in the long run if restricted to public lands. 



Projected Trends in Areas 



In recent years, the area of forest land and rangeland has been declining as these 

 lands have been converted to other uses. The water area has been increasing due to 

 the construction of ponds and lakes (reservoirs). The total output of products from 

 forest land and rangelands is likely to be affected in the future by changes in area. 



Area projections from the 1989 RPA Assessment are used in this update. Area 

 changes are generally slow to occur and an update of projections would probably 

 show only minor changes. These projections include allowances for the provisions of 

 the Farm Bills of 1985 and 1990, which had the intention of converting highly erodible 

 cropland to grass or forest land. Partly because of these programs, the area of 

 rangeland is projected to increase from current estimates of 770 million acres to 820 

 million by 2040. 



18 



