THE ECOLOGY OF THE UPPEE GANGETIC PLAIN. 3li 



as the village water supply and laundry, as the village sanitary system, 

 and finally as a source of water for irrigation. Ponds that appear 

 promising places for study one year are devastated the next (Fig. 9). 

 The result is that for the most part succession must begin as the 

 beginning each year. Instead of the topographic succession, pools 

 present year after year mUch the same appearance for a given season, 

 and seasonal rather than topographic succession is conspicuous. This 

 renders the study of topographic succession very difficult, and every- 

 where emphasizes the struggle that is going on between man and 

 nature, and the balance that has become established between them. 

 By far the largest part of the area is as far advanced in succession as 

 is possible under existing conditions (Fig. 11). 



Details of topographic succession, 



In more favored parts of the earth where vegetation has a 

 chance to develop naturally, it is possible to study with considerable 

 precision the gradual development of the flora from the most primi- 

 tive conditions to the most advanced association of plants that 

 the area can support; For the most part studies in plant succession 

 have been made in temperate regions, where there is but one 

 vegetational season, the summer or growing season. This is followed 

 by a winter season during which the vegetation is at more of less 

 of a standstill. In the Upper Gangetic Plain there is no season 

 in which growth is impossible. Growth is checked and the vegeta- 

 tion modified by the aridity of the hot season, and at all seasons and 

 at every stage it is interferred with even to the extinction point 

 by the human factors. Therefore it is not an easy matter to trace 

 the steps of topographic succession. The problem is further com- 

 plicated by the seasonal succession. Yet in spite of the difficulties, 

 it has been possible to find a few favorable spots which give a clue 

 to the early stages of succession, and others which indicate what 

 the higher stages would be if the human factors were lessened or 

 removed. 



Stages is the topographic succession. It is convenient to divide 

 the succession into the following stages : — 



1. Aquatic stage. 



2. Wet meadow stage. 



3. Dry meadow stage. 



4. Thorn scrub stage. 



5. Pioneer monsoon deciduous forest stage. 



6. Climatic climax monsoon deciduous forest stage. 



