THE LAND VERTEBRATES OF RIDGEWAY BOG, WIS- 
CONSIN: THEIR ECOLOGICAL SUCCESSION AND 
SOURCE OF INGRESSION 
By Hartley H. T. Jackson, Ph.D. 
I. Introduction 4 
II. Physiographic Features of the Region 12 
A. General Topography 12 
B. Climate 13 
HI. The Ridgeway Bog 14 
A. Description of the Bog 14 
B. Ecological Associations 15 
1. Aquatic Association 17 
2. Sedge Association 17 
3. Cassandra Association 18 
4. Tamarack-Spruce Association 18 
5. Cedar-Balsam-Hemlock Association 19 
6. Roadside Association 20 
7. Hillside Association 21 
IV. Ecological Succession 22 
V. Source of Ingression of the Biota 33 
VI. Summary 46 
VII. Acknowledgments 47 
VIII. Bibliography 47 
I. INTRODUCTION 
Papers referring to animals inhabiting bogs in various locali- 
ties have been numerous, but the majority of these have been 
mere ‘‘local lists” with casual mention of certain species occurring 
in “bogs,” “swamps,” “tamaracks,” or such other designation 
as best fits their writer’s use — contributions of little value towards 
solving the problems in the ecology, distribution, or evolution 
of the animals concerned. More recently bog habitats have been 
studied somewhat more carefully. 
Ruthven (Ruthven, and others, 1906) in a general ecological 
survey of the Porcupine Mountains in northern Michigan inves- 
tigated the fauna and flora of certain bogs in which the bog so- 
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