40 



THE STUDY OF PLANT COMMUNITIES ■ Chapter HI 



The use of permanent quadrats has been advocated by many 

 ecologists, but few have followed their own excellent advice. 

 Whenever there is a remote possibility that a sampling area may 

 again be visited for further study, the quadrats should be marked 

 with permanent markers, for surprisingly worth-while results may 



FlG. 15. Paired pictures illustrating slow development of vegetation on 

 »cks on Isle Royale. Lower picture taken seventeen years after upper.— 



rocks on Isle Royale. Lower picture 

 Photos by W. S. Cooper™ 



be obtained by restudying identical areas after a period of years. 

 Such results are often valuable out of all proportion to the effort 

 required, especially when compared to the initial study. Most 

 quadrat studies are planned for immediate results and to help solve 

 problems of the moment, but with little extra effort they could be 

 used to yield returns over a period of years. Actually it would be 

 well to consider the possibility of making every quadrat permanent. 

 When Dr. W S. Cooper made his now widely known study 

 of vegetation on Isle Royale in Lake Superior, he photographed 

 his sampling areas and carefullv marked the spots even though he 

 had no definite plan for restudying the area. Seventeen years later 



