Photography is a well known process, but is probably under utilized as a technique for quantitative ecological monitoring. Though it may be an under utilized technique, recent projects comparing newly acquired and historic imagery offer dramatic contrasts resulting from progressive environmental alterations. For example, the USGS Repeat Photography project documents glacial recession in Glacier National Park by comparing imagery taken less than 100-years ago with recently acquired imagery to clearly illustrate the consequences of climate change (see image to right).
So, we are all familiar with photography as a means of capturing candid snapshots and artistic landscapes, but using photography to objectively capture the status of natural resources is equally valuable. Combine that with the fact that the Appalachian Trail environmental monitoring program relies on the contributions of many people, some professional researchers, some volunteers; some very experienced, some not. The amalgamation of programs, experience and expertise creates potential problems that a technique which objectively captures information regardless who is using it is of tremendous value.