APPLIED ECOLOGY 



355 



Land evaluation on an ecological basis has been made use of at 

 various times, and a simple illustration will serve to indicate the 

 possibilities. Not long ago the construction of dams for water 

 control in the upper Mississippi River necessitated legal action to 

 fix the value of much lowland that would be flooded when the 

 project was completed. One of the basic questions involved the 

 establishment of criteria for determining which acreages were 

 cultivatable and which were not. It was possible to show by means 

 of the natural vegetation, regardless of whether the land had or 

 had not been cultivated, which areas were only rarely flooded 

 and, therefore, desirable agriculturally, which flooded frequently, 

 and which were always too wet for cultivation. Once this was 

 worked out it could be applied generally throughout the area. 

 The information was used effectively for establishing equitable 

 land values in several court proceedings. 



Range and Pasture Indicators.— The use of plants as indicators 

 is basic to range management. 248 A knowledge of the important 

 indicator plants and the application of their meaning to handling 

 of grazing land has become fundamental to successful manage- 

 ment. Plant indicators are used to judge the condition of the range 

 and particularly to recognize signs of deterioration or improve- 



FlG. 189. Death of shrubs and a browse line in a pasture as indicators of 

 too heavy grazing by cattle— U. S. Forest Service. 



