28 



ECOLOGY 



Related to zonation, since all eco- 

 logical facts are related, is the process 

 of succession. The histor)' of the fresh- 

 water pond or lake is the story of suc- 

 cession. Whether the pond originated 

 as an ox-bow cut from a meandering 

 stream, or whether it fills a depression 

 hollowed out by wind, or by a glacier, 

 or is dammed by a terminal moraine or 

 a land slump it has had a histor)' influ- 

 enced by water and wind and plant life. 

 Once the pond was larger than now; 

 unless natural processes are interfered 

 with by man it will continue to shrink 

 in size. As filling continues, in place 

 of pondweeds and open water there 

 are bulrushes and cat-tails, for these 

 have extended into the former lake. 

 The plant remains of the bulrush and 

 cat-tail zone change soil conditions so 

 that the soil becomes more suitable for 

 marsh grasses; marsh grasses no longer 

 can live in their former place, for they 

 have rendered it too dry, so meadow 

 grasses and flowering herbs take their 

 place; finally the short grass or the 

 spruce trees or the oak chaparral fol- 

 low into where meadow recently flour- 

 ished. With the disappearance of open 

 water there was no place for pond- 

 weeds; as drying continued the bul- 

 rushes and cat-tails were crowded out 

 by marsh plants, and the marsh plants 

 gave way to meadow plants— all of 

 these changes part of a definite and, as 

 it might appear, a pre-arranged succes- 

 sion. 



With changes in plant population 

 the animal population likewise is 

 bound to change: fishes disappear, then 

 frogs, salamanders, and sandpipers. 

 The fauna soon consists of animals 

 fitted to the new conditions. Tliose 

 animals which do not fit the new con- 

 ditions cither die or go elsewhere; the 

 animals which find the environment 

 now well suited to their life activities 

 multiply, and other animals from out- 

 side come in to become a part of the 

 animal population. 



Subjects for research in ecology are 

 many and varied; they may engage the 

 general zoologist or botanist or such 

 specialists in biology as entomologists, 

 ornithologists, grazing experts, foresters, 

 agronomists or, again, geographers, ge- 

 ologists, and psychologists. All of these 

 make use of the fundamental sciences: 

 mathematics, astronomy, physics, and 

 chemistry. Ecology can be just as ab- 

 struse as other sciences, for it uses a 

 complex terminology, employs graphs, 

 formulae, and tables of variance— from 

 all of which I spare you. The ecologist 

 is much interested in theoretical mat- 

 ters, yet he is not one to "sit apart and 

 reason high." He travels to the wilds of 

 Africa and to the tundra of Siberia. He 

 carries on laborious and time-consum- 

 ing studies in field and laboratory, 

 spends hours and hours in watching the 

 behavior of animals or in testing them 

 experimentally. His long-time experi- 

 ments in forestry run beyond the life 

 experience of any one man, and are so 

 planned that they must be finished by 

 others. 



*«##*# 



Before ecology' had become recog- 

 nized as a discipline deserving a place 

 and name of its own those who carried 

 on research in plant and animal rela- 

 tions published their results in the 

 established journals. Perhaps some 

 ritles of research papers may be cited to 

 suggest the kinds of investigation car- 

 ried out by ecologists. I do not cite any 

 which are primarily devoted to agricul- 

 ture; there are hundreds of these pub- 

 lished every year, for, as already sug- 

 gested, agriculture is essentially applied 

 ecology. And now, for a few of the 

 subjects culled from periodicals: 



Native grasses for erosion control; Tree 

 rings and chronology in the Southwest; 

 Present-day vegetation compared with 

 that of the Glacial period; Spawning of 

 red salmon; Altitudinal range of rattle- 



