Prairie dogs (Cynomes spp.) were historically essential to the health of prairie ecosystems by acting as both a keystone species and transforming the landscape as ecosystem engineers. However, with increasing anthropogenic activities in the west, the positive role that prairie dogs once played may have changed.
Prairie dog populations around Boulder, Colorado have increased from 55 colonies in 1997 to 410 colonies in 2010, and based on previous research, many advocates believe that the positive influence of prairie dogs on the diversity of birds, small mammals, predators, and arthropods will persist in Boulder. Often overlooked and understudied is the effect that the highly fragmented landscape will have on prairie dog populations and their potential change in behaviors within an urban landscape. Climate change has given many invasive plant species a foothold in Boulder; however, urban prairie dogs may also be facilitating the expansion of exotic species by altering their competition dynamics with native species. This contrasts with the positive role that prairie dogs historically played in grassland ecosystems.
The dataset for this analysis is comprised of 70 paired vegetation sample transects located in Boulder County from 1997 to 2010 and an additional 153 transects conducted in 2009 and 2010.
Results/Conclusions
Data analysis suggests that prairie dogs are significantly altering vegetation dynamics in Boulder. Areas occupied by prairie dogs have significantly less litter (p <0.001) and standing dead vegetation (p = 0.007), and significantly more bare soil (p < 0.001) than areas unoccupied by prairie dogs, suggesting the potential for major changes in microclimatic variables. Occupied areas have significantly more invasive forbs than unoccupied areas (p <0.001). Certain invasive species, such as Convolvulus arvensis are uncommon in Boulder (mean cover % = 2.53 ± 0.34 (SE)), but overtake areas occupied by prairie dogs (mean cover % = 13.41 ± 1.40 (SE)).
In Boulder’s urban landscape, prairie dogs are changing vegetation dynamics in a magnitude previously undocumented. While the animals still perform some traditional functions, their impacts at the urban-wildlands interface have changed. It is imperative to understand how urban prairie dogs will alter vegetation composition and dynamics in this system, and manage the system appropriately, in order to prevent the area’s transformation into a less desirable ecosystem, with potentially detrimental effects across tropic levels.