Plant community composition and structure monitoring for Wind Cave National Park: 2011-2015 summary report

Ashton, Isabel; Davis, Christopher

The Northern Great Plains Inventory & Monitoring Program and Fire Effects Program have been monitoring vegetation in Wind Cave National Park for over 18 years. While methods have changed slightly, this report summarizes data from 97 locations from 1998-2015. Below, we list the questions we asked and provide a summarized answer, for more details see the Results and Discussion section. We conclude with a Natural Resource Condition Table (Table ES-1) that summarizes the current status and trends in a few key vegetation metrics. 1. What is the current status of plant community composition and structure of WICA vegetation (species richness, cover, and diversity) and how has this changed from 1998-2015? The ponderosa pine woodlands and mixed-grass prairie within the boundaries of WICA are characterized by moderate to high native species richness. The closed canopy forest generally maintains lower species richness than the open grassland areas. We found no significant trends in native diversity or evenness from 1998 to 2015. Invasive annual brome grasses are an emerging threat in WICA, and keeping them in low abundance will help maintain native plant diversity. Other exotics, such as Kentucky bluegrass are more prevalent, but there is no evidence of an increasing trend in their cover. 2. What are the differences and similarities in forested and grassland condition and trends? We examined the status and trends in native species richness, exotic species cover, and litter cover between forest and grasslands plots in WICA. We found that grassland plots had higher native richness and higher cover of annual brome grasses but there was not a difference in the relative cover of exotic plant species. Despite some differences in species composition, trends over time appear consistent in grasslands and forested plots. This suggests that both ecotypes are responding similarly to climate and other external drivers. 3. How do trends in vegetation correlate with climate and fire history? The large variability in the climate of WICA has made it difficult to discern strong patterns linking temperature, precipitation, and plant community structure (e.g. exotic cover, species richness). A longer time series of vegetation data will make it easier to elucidate trends in the future. WICA has been using prescribed fire as a management tool since the 1970s. There was no difference in native diversity among plots that had burned recently and those that had not burned for over 25 years. However, the sites which burned recently have a lower cover of annual brome grasses than sites that have not burned in over 20 years. Ongoing adaptive management programs and research will provide better guidance to the park on whether prescribed burns are an effective tool to reduce the cover of annual bromes. 4. What, if any, rare plants were found in WICA long-term monitoring plots? We identified 2 rare plant species in WICA between 1998 and 2015- nylon hedgehog cactus (Echinocereus viridiflorus) and a moonwort species (Botrychium sp.). These plants are found in such low abundance and in such few plots, it will take many years to determine any trends in rare plant cover. We recommend a more targeted survey of rare plants be completed when funds are available.

Plant community composition and structure monitoring for Wind Cave National Park: 2011-2015 summary report

Series

See also

Collections