Artificial artesian wells have existed in the San Luis Valley of south central Colorado for over 100 years and are an important source of water for livestock and wildlife. When Great Sand Dunes National Park and Preserve (GRSA) expanded its boundaries in 2000, 10 of these wells were within the new park boundary. In 2010, the National Park Service capped these wells to restore the surrounding habitat to a more natural state, which was severely disturbed from cattle and wildlife trampling. To study changes after well capping, we compared the plant communities in 2011 and 2012 and measured plant cover, species frequency, and species diversity at recently capped wells on GRSA, at open wells (i.e., with water) on adjacent private lands of The Nature Conservancy, and at reference sites. In general, there was little difference in percent plant cover and species diversity between well types. For percent cover, annual variation and distance from well heads were the best predictors for the native and exotic plant species, respectively. Plant species composition varied by well type with reference sites having the greatest frequency of native plants per site, and capped well sites having the greatest frequency of exotic plants per site. For native plants, reference sites had highest species diversity, while capped wells had highest community evenness. Overall, our results suggest that in the short term, native plant populations have changed little after well capping, but the frequency of exotic plants has increased at capped well sites relative to reference sites.
Garza, Sarah J.; Bowser, Gillian; and Wilson, Kenneth R.
"Plant community changes following closure of artesian wells in Great Sand Dunes National Park, Colorado,"
Western North American Naturalist: Vol. 74
, Article 7.
Available at: http://scholarsarchive.byu.edu/wnan/vol74/iss3/7