670 Ecology 



CONSERVATION 



One of the many problems facing us today is that of the conserva- 

 tion of natural resources. These include the soils, forests, minerals, 

 streams, and wildlife. The conservation of these resources is impor- 

 tant not only to us but to future generations. 



At one time, conservation was regarded as the non-use of these 

 vital resources. Today the attitude is quite changed ; instead it is be- 

 lieved that these should be used, but in an intelligent manner. Trees 

 may in this way be cropped from the forest, but replanting takes care 

 of future needs. Game may be hunted, but means for natural replenish- 

 ment must be considered. For animals the conservation may consist 

 of limits on numbers of individuals shot, provision of nesting sites, 

 supplies of food during periods of stress, and protection during the 

 breeding season. Many attempts at conservation have failed because 

 the well-meaning persons in charge did not base their practices on ade- 

 quate biological information. 



Interference With Food Networks. — Frequently man has re- 

 moved predators in order to help certain species which he favors to 

 increase in numbers. This well-meant practice frequently has unfore- 

 seen consequences. One classic example is that which occurred in 

 the Kaibab plateau of Arizona. 



Under natural conditions there were about 4,000 deer in this pre- 

 serve. Their numbers were kept in check by numerous wolves, coyotes, 

 and pumas. About 1905 there began an intensive efifort to increase the 

 deer population by killing off these natural predators. With this pres- 

 sure removed, the number of deer increased in the typical accelerated 

 growth curve. When the number of deer reached about 40,000 in 1920, 

 the first indication of trouble appeared. When the population reached 

 60,000 it was noted that some fawns were dying of starvation due to 

 the depletion of the natural food. Despite more warning, nothing was 

 done to control the number of deer. As a result, the population in- 

 creased to 100,000 in 1924. This was far beyond the carrying capacity 

 of the forest, and during the next two winters, 60 per cent of the 

 herd starved. In 1925, the population was down to 40,000. In 1939, 

 there were about 10,000 deer with only a few pumas and a very 

 much damaged forest. For many years this has stood as a monument 

 to bad conservation practices. 



This is but a single example of a whole series of bad practices which 

 have resulted in unfortunate situations. 



