NIBIBERS : STATISTICS 4d 



ficance of animal inter-relations. Most of the urgent 

 economic ecological problems are concerned with 

 animal population problems : how many whales are 

 left in the Antarctic seas, whether too many fish 

 are being taken off the bed of the North Sea, whether 

 the muskrat is spreading and increasing in England 

 or Finland, whether a certain insect pest will be 

 more or less abundant this year, how to check the 

 increase of malaria organisms in the blood of infected 

 human beings, whether the greatly increased trapping 

 of snowshoe rabbits in Canada will affect the numbers 

 of IjTix which prey upon them, the causes of periodic 

 decrease of partridges in England, and so on. 



The stimulus to carry out censuses of wild animals 

 has thus come to a great extent from the pressure of 

 economic circumstances, often from general motives 

 of stock-taking — the estimation of natural resources 

 in a country. At the same time ecologists have been 

 led on naturaUy from a study of natural animal 

 communities towards a study of their population 

 problems. These problems form the highest and 

 most complex stratum of ecological work, and the 

 science is yet in an early stage, through a lack of 

 abundant facts with which to work. We may hope 

 to see during the next two or three hundred years 

 the development ^ of a science of animal numbers 

 which will take its place beside older sciences such 

 as astronomy and chemistry that took equally long 

 to reach a stage in which the power of prediction was 

 established with certainty. This science of animal 

 numbers is of very great importance in the task of 

 combating various animal and plant pests which 

 attack man and his domestic animals and plants, 

 and wild species upon which he also depends for 

 material resources or for amenities. At the same 

 time a correct understanding and weighing of the 

 evidence for the theory of natural selection and 

 methods of evolution in general also awaits the 

 further development of this phase of animal ecology. 



