Introduction 



Shifts in the composition of plant species are often linked to 

 changes in the structure and function of ecological systems. But 

 detecting such shifts in relatively undisturbed natural systems, 

 such as rangelands and forests, is often difficult because changes 

 occur very slowly and therefore are quite subtle. Often, changes 

 aren't recognized because substantial change seldom occurs within 

 a single human generation; rather, readily detectable change usu- 

 ally requires the span of several generations. 



This publication is an attempt to provide researchers, naturalists, 

 land managers, policy makers, and the general public with a new 

 awareness of and appreciation for the subtle, yet real changes that 

 have occurred over the past 80 to 90 years in the Northern Great 

 Plains. We recorded the changes by repeating landscape photo- 

 graphs, which we augment with descriptions derived from on-site 

 visits. The challenge to us authors, as well as our readers, revolves 

 around how we might use the information presented here as a 

 means for improving land stewardship. 



The earliest photographs were taken by Dr. Homer Shantz, Univer- 

 sity of Arizona, from July 14, 1908 to September 1, 1937. 



The second set of photos was taken of the original sites from June 

 13, 1958 to August 18, 1960. Shantz took a portion of these before 

 he died in 1958 while on the road rephotographing the sites. He 

 was accompanied on that trip by Dr. Walter S. Phillips, University of 

 Arizona, who completed the repeat photography task in 1959, with 

 the assistance of University of Arizona student Freeman Smith (now 

 Dr. Freeman Smith, Colorado State University), and in 1960 in the 

 company of his wife, Thelma K. Phillips. 



The 1998 photographs were taken from July 21 to August 5. 1998, 

 by Dr. Charles Kay, Utah State University. 



Sites were again visited during the summer of 1999 by Keith 

 Klement, U.S. Department of Agriculture, Agricultural Research 

 Service, Fort Keogh Livestock and Range Research Laboratory, 

 Miles City, Montana. 



The original photographs, first retakes, and associated site descrip- 

 tions were published by Phillips in 1963 in Photographic Documen- 

 tation: Vegetational Changes in Northern Great Plains. A history of 

 the two earlier photographic expeditions is contained in that publi- 

 cation. 



The current publication includes repeat photographs from 42 of 

 Shantz's 81 original sites. We limited our sites to rangelands. For 

 most sites, four photographs are reproduced: (1) Shantz's black and 

 white original, (2) the 1958-1960 black and white retake, (3) a 1998 

 black and white retake, and (4) a 1998 color retake. 



