Department of Biology

Ecosystem resilience to prairie dog disturbance reveals opportunities and tradeoffs for rangeland management

Dr. Lauren Porensky
U.S. Department of Agriculture

February 22, 2023
4-5pm

Hosted By Morgan Frost and Dr. Sally Koerner

Abstract:

In the western Great Plains, black-tailed prairie dogs (Cynomys ludovicianus) have major impacts on vegetation structure, cover, biomass, forage quality, and composition. These vegetative changes, in turn, shape outcomes for both livestock and wildlife. Recent research suggested that shortgrass steppe vegetation is relatively resilient to prairie dog disturbance; within 5 years of prairie dog removal. However, it is unclear whether these results also hold in northern mixed-grass prairie, where plant species composition is quite different. We used a large natural experiment to examine vegetation change after prairie dog removal in northeastern Wyoming. After a large epizootic decimated prairie dog populations across the region in late 2017, we monitored vegetation and wildlife on former prairie dog colonies and uncolonized sites through two wet years (2018-2019), a drought year (2020) and a more average year (2021). We found that when a plague event was followed by above-average moisture, formerly colonized sites produced 50-100% more biomass than formerly uncolonized sites. This ‘post-plague biomass bump’ was driven mostly by perennial cool-season grasses and, to a lesser degree, annual forbs. We did not observe large increases in annual brome abundance on former colonies. These results suggest that if rainfall is adequate, active restoration (e.g., reseeding) is not needed to revegetate northern mixed-grass prairie after prairie dog removal. On the other hand, wildlife associated with prairie dog colonies displayed dramatic declines after the removal of prairie dogs, revealing important tradeoffs for rangeland management and conservation in this unique ecosystem.