Naturalist David Bertelsen (image) University of Arizona Caption Dave Bertelsen hikes Finger Rock trail in the Santa Catalina Mountains. Tucson, Ariz., can be seen in the valley below. Bertelsen has been hiking the trail and recording the locations of plants in bloom for more than 25 years. Credit Ben Wilder. Usage Restrictions This photo may only be used to illustrate a story about the research described in the accompanying news release, Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.