338 THE STUDY OF PLANT COMMUNITIES ' Chapter XII 



cutting and burning all hollow snags on a wildlife refuge. 153 Such 

 conflicting activities have not been uncommon in the name of 

 conservation. Some government agencies have spent millions for 

 flooding marshes and improving them for wildlife while other 

 agencies were attempting to drain marshes of questionable agri- 

 cultural value. Great dams have been built for reclamation pur- 



FlG. 181. The deposition of silt and sand behind a dam in this fashion de- 

 feats its purpose of water storage and reduces the efficiency as a source of 

 hydroelectric power.— U. S. Soil Conservation Service. 



poses, but the watersheds above them have been ignored. 227 With 

 continued lumbering and grazing, the reservoirs are silting in so 

 rapidly that the usefulness of the dams promises to be short-lived. 

 To assure integration of such activities may not require a "declara- 

 tion of interdependence" 250 but certainly the recognition of the 

 interdependence of biological phenomena is necessary. This end 

 will certainly be served if those responsible are ecologically trained 

 or have an ecological point of view regardless of their special in- 

 terests. 



Soil Conservation.— The recognition of soil conservation as a 

 national problem is of recent origin. The Soil Conservation Service 

 was made a permanent bureau of the U. S. Department of Agri- 

 culture in 1935 athough it originated as the Soil Erosion Service 

 in the Department of the Interior in 1933. Since then great prog- 



