Plant Community Monitoring at Hot Springs National Park, Arkansas: 2007–2024

Leis, Sherry

doi:10.36967/2317128

Hot Springs National Park, Arkansas, is known for thermal hot springs but the forested landscape also contributes to the park’s mission. The forests protect the hot springs recharge zone and provide recreational opportunities. The Heartland Inventory and Monitoring Network has conducted long-term plant community monitoring since 2007 in the park’s forests. We collected data on seven monumented sites (50 m × 20 m) in 2007, 2014, and 2024. While midstory and overstory data were recorded across the whole 0.1 ha area, ground flora, ground cover, and canopy closure were observed in ten 10 m2 plots. Plots were averaged to the site level and sites were averaged to represent the conditions at the park scale. The environment at Hot Springs National Park includes regular periods of moisture and drought. The 2024 monitoring occurred during a period of above average precipitation. While maximum temperatures in 2024 were similar to the past, minimum temperatures were warmer during much of the year. The ground surface was more vegetated and had less leaf litter than in other years, possibly because of prescribed fires at two sites. The forested sites were similar in structure across years, but midstory tree (trees between 5 and 15 cm diameter at breast height [DBH]) density increased in 2024. We noted that abundance of the fire-sensitive species eastern redcedar (Juniperus virginiana) and basal area of the fire-tolerant shortleaf pine (Pinus echinata) had small increases during the last monitoring period. However, stem density of shortleaf pine decreased. We noted few problematic species (invasive species) in the ground flora, but sacred bamboo (Nandina domestica) expanded at one site. Gamma diversity (park-wide plant diversity) was greatest in 2024. Quality assessment procedures indicated a high level of agreement between observers for species (89%) and an acceptable level of agreement for percent cover (95% of observations within one class). Although fire effects monitoring reported that ecological objectives have been met in burned sites, our park-wide results differ with respect to pole-sized tree reduction, mean species richness increases, and vegetated cover increases. As a result, we suggest that wider use of prescribed fire may be helpful for the forest as a whole.

Plant Community Monitoring at Hot Springs National Park, Arkansas: 2007–2024

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