Status and trend of upland vegetation and soils at Dinosaur National Monument, 2010–2020

In 2009, the Northern Colorado Plateau Network began long-term monitoring of pinyon-juniper woodlands, high-elevation sagebrush, and low-elevation sagebrush shrublands in Dinosaur National Monument. Sagebrush communities have been impacted by fire and grazing in the past, and some areas have converted to an alternative grassland state, which can be dominated by native or exotic species. Pinyon-juniper woodlands are varied in structure but comprise the majority of plant communities throughout the monument. The primary goals of this monitoring are to track the status of these ecosystems and determine trends, or how they are changing over time. This report summarizes ten years of monitoring data and addresses the following questions: (1) What is the status and trend of vegetation and soil indicators for high-elevation sagebrush, low-elevation sagebrush, and pinyon-juniper woodland communities?, and (2) How do climate, grazing, and fire history influence observed status and trend? Results showed that in sagebrush communities, native cool-season perennial grasses decreased in cover while exotic annuals rapidly increased. Cover of big sagebrush (Artemisia tridentata) was on the lower end of known reference conditions but slowly increasing. Biological soil crust and soil stability were both increasing in sagebrush communities indicating improving conditions, but bare soil was also increasing in high-elevation sagebrush. In pinyon-juniper woodlands located in the south-central area of the monument, tree cover was stable but sapling density was decreasing. Cover of exotic species was low in pinyon-juniper woodlands. Managers should consider actions to control the rapid increase of exotic species (primarily cheatgrass) and protect native cool-season grasses in high- and low-elevation sagebrush communities.