interaction between two types of ecosystems, a 

 terrestrial forested watershed and a stream running 

 through the watershed. 



1971 1972 1973 



$0.33 $0.37 $0.37 



Department of the Interior.— Ecological research 

 on stability and interactions is carried on by the Bureau 

 of Sport Fisheries and Wildlife, the National Park 

 Service and (to a limited extent) by the Geological 

 Survey as a support function to their primary missions. 



1971 1972 1973 



$1.45 $1.40 $1.39 



Smithsonian Institution.— One of the major ac- 

 tivities of the National Museum of Natural History and 

 the Smithsonian Tropical Research Institute is the 

 description of biota of ecosystems and areas through 

 time. This work includes the abundance and 

 distribution of flora and fauna and changes in species, 

 distribution, and abundance with time. The functions 

 and relationships of organisms with the environment 

 involve detailed studies on effects of climate, solar 

 radiation, toxic materials, and other factors on species. 

 The relationships between organisms in the ecosystem 

 are being studied in Panama and at Chesapeake Bay 

 with regard to their importance in ecosystem function 

 and stability. Relationships involving social patterns, 

 food relationships, pollination, and seed dispersal are 

 being studied. 



1971 1972 1973 



$0.80 $1.00 $1.30 



Department of Agriculture.— Research is carried 

 out to define and quantify the interactions of plants and 

 animals with their environments and with each other. 

 A system of Natural Areas serves as a baseline on 

 which the functioning of undisturbed ecosystems is 

 studied. Research on the structure and functioning of 

 forest, range, and desert ecosystems (in cooperation 

 with the International Biological Program) is also 

 included. Similar studies are underway on ecosystems 

 that have been manipulated in various ways. The 

 ecological relationships developed here can then be 

 used as inputs for research on management systems. 



1971 1972 1973 



$3.24 $3.66 $3.48 



59 



