Excerpt from Biological Bulletin, Vol. 22: Of the Marine Biological Laboratory, Woods Hole, Mass
In the preceding paper we presented certain facts concerning ponds, together with a statement of succession in the pond at the head of Lake Michigan, without entering into its causes . Succession in ponds is due to many causes. It is only under the most favorable conditions that we can separate these causes one from another without long and careful investigation. The first attempts of ecologists in this line were considerations of the obvious general facts, such as the accumulation of organic detritus and the increased denseness of vegetation. We can give hen.1 hint at the more specific changes in the ponds and the relations of these to fish. The subject is one for cooperative, research. At present some of the workers and the necessary funds are not available, and the ponds are being destroyed rapidly. It is therefore improbable that the study can be carried further. This paper deals with the results of a preliminary investigation of the ponds for the purpose of learning something of the causes of distribution and succession of fish and other organisms in ponds.
II. The Present Character And Content of The Ponds.
The ponds with which we are concerned are shown on the map, p.131, of the preceding paper of this series. This map is essential to the understanding of the data of the present paper. Tin ponds here considered are an ecological age series, ecological age being determined by a study of amount of sand bottom, humus, etc., as shown in Table I. below. The physiographic history of the region is in full accord with the facts used in deciding age though in this case physiographic history is not essential to the decision. The pond designated as I is ecologically youngest, 14 the oldest, and the others intermediate. The measurements, analyses, and quantitative study were carried out on Pond i.c (west section), 7a, and 14b of the map. Some qualitative records from the other parts of pond 5c, from 5b, and 4d, are included with those of the ponds in which the other work has been done.
About the Publisher
Forgotten Books publishes hundreds of thousands of rare and classic books. Find more at www.forgottenbooks.com
This book is a reproduction of an important historical work. Forgotten Books uses state-of-the-art technology to digitally reconstruct the work, preserving the original format whilst repairing imperfections present in the aged copy. In rare cases, an imperfection in the original, such as a blemish or missing page, may be replicated in our edition. We do, however, repair the vast majority of imperfections successfully; any imperfections that remain are intentionally left to preserve the state of such historical works. Это и многое другое вы найдете в книге Biological Bulletin, Vol. 22 (E. G. Conklin)