I certify that I have read this study and that in my opinion it conforms to 

 acceptable standards of scholarly presentation and is fully adequate, in scope and 

 quality, as a dissertation for the degree of Doctor of Philosophy. 



MJ jM'-^lM. 



William Seaman, Jr. 

 Associate Professor of 

 Forest Resources and 

 Conservation 



j^^Lu^ 



This dissertation was submitted to the Graduate Faculty of the Department 

 of Zoology in the College of Liberal Arts and Sciences and to the Graduate School 

 and was accepted as partial fulfillment of the requirements for the degree of Doctor 

 of Philosophy. 



August 1990 Dean, Graduate School 



