Plant community composition and structure monitoring at Fort Union Trading Post National Historic Site: 2019 data report

Davis, Molly

This report presents the results of vegetation monitoring efforts in 2019 at Fort Union Trading Post National Historic Site (FOUS) by the Northern Great Plains Inventory and Monitoring Network (NGPN). This was the ninth year that NGPN conducted field work at FOUS. Crew members from NGPN visited nine long-term monitoring plots to collect data on the plant communities at FOUS. Six plots were part of the regularly scheduled monitoring interval. Three additional plots were read in the Bodmer Overlook Unit to evaluate the effects of cattle grazing in the unit. This work is part of a long-term monitoring effort designed to provide a better understanding of the condition of the vegetation community and how it changes over time. NGPN staff measured species richness, herb-layer height, native and non-native species abundance, ground cover, and site disturbance at each of the nine plots. In three plots where woody species were present, tree regeneration, tall shrub density, tree density, and woody fuel loads were also measured. In 2019, the NGPN monitoring crew identified 94 unique plant species in nine monitoring plots. Of those species, 15 were exotic species. The five plots located in the Bodmer Overlook Unit were more diverse and had more native species than the four plots located in the Upland Terrace Unit near the fort. No trees or woody fuels were present in the nine plots, but the crew did identify one green ash (Fraxinus pennsylvanica) seedling. One rare plant, alyssumleaf phlox (Phlox alyssifolia, ranked G5/S1 in North Dakota), was observed during our surveys. The entire Bodmer Overlook Unit (approximately 30 acres) was grazed by cattle in early May, but our field crew noticed very little grazed vegetation when they visited in late July. The most commonly observed disturbance was small mammal activity.

Plant community composition and structure monitoring at Fort Union Trading Post National Historic Site: 2019 data report

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