A Study of the Occurrence of Amphibians in Relation to a Bog Succession, Itasca State Park, Minnesota

Abstract

The occurrence of animals in relation to various stages of plant succession has both fundamental and applied significance. While developing field projects for classwork at the Lake Itasca Forestry and Biological Station in northwestern Minnesota, the authors coordinated portions of the field work by students in a course in animal ecology taught by the senior author and plant ecology taught by the junior author to demonstrate this phase of ecology. The present report summarizes the results of several years of collecting amphibians and sampling plant occurrence in a bog succession that according to Conway (1949) . . presents an apparently perfect example of the successional stages of this locality. The area in which the studies were carried out is located in Bog D as shown by Conway (1949) in her Figure 2. More specifically this area lies in Section 30, T 143 N, R 35 AW in Hubbard County, Minnesota. Field data on amphibians were obtained about mid-August of the years 1949 through 1953 by class members of the animal ecology course. Reconnaissance surveys, as described later, have been made by plant ecology groups at about the same time each year except 1953. Following field work a seminar has been held annually to discuss the current and previous data and their various implications. In 1951, 1952 and 1953 the stomach contents of the frogs collected were examined. Mr. \'Villiam Tunis, Dr. Herman T. Spieth, and Dr. Alvah 0. Peterson identified these materials following preliminary treatment by class members. Detailed results of these and other amphibian food habit studies will be reported elsewhere. In August, 1953, Mr. A. Grewe and L. D. Frenzel, members of a course in Organisms. Microclimate and Weather under the direction of Dr. Donald B. Lawrence conducted certain studies of the microclimate in the area. The authors appreciate sincerely the opportunity of using these data in the present discussion.