Renée Rondeau has been working on a vegetation comparison study with a 20-year time frame at the U.S. Air Force Academy in Colorado Springs. She chose sites that in 1991 were observed to be free, or nearly free, of weeds and looked at whether they were still weed-free in 2011. Here are four repeat-photography pairs of different native plant communities, and the observed change in species composition (click photos for larger versions):
Although weeds are prolific in and around the Academy, these high quality native plant communities have so far successfully resisted significant weed invasion. This result indicates that functioning, high quality occurrences of native vegetation are both resistant and resilient. Clearly, conserving high quality plant community occurrences is important and should be regarded as an efficient tool for weed control, because weed management and native vegetation restoration is expensive and difficult.
More information about noxious weeds in Colorado and why controlling them is important is available from the Colorado Noxious Weed Management Program.
