Sagebrush steppe vegetation monitoring in Craters of the Moon National Monument and Preserve: 2019 annual report

Nicolli, Melissa

As part of the Upper Columbia Basin Network’s sagebrush steppe vital signs monitoring program, a survey of sagebrush steppe ecological condition was conducted in June and July 2019 in Craters of the Moon National Monument and Preserve (CRMO) following methods outlined in the Upper Columbia Basin Network monitoring protocol (Yeo et al. 2009). The plot-based surveys occurred within 28 sampling frames and included 1527 plots, each 1 m² (Figure 1). Cover of exposed soil and of principal native and non- native plants or genera were estimated in plots randomly placed throughout the sampling frames. Plot locations were drawn using a spatially-balanced random sampling design, Generalized Random Tessellation Stratified (GRTS), which ensures a good representative random and dispersed sample within each sampling frame. Sagebrush steppe is one of the most threatened ecosystems in the intermountain west, and land use practices both within and adjacent to UCBN park steppe communities have resulted in fragmented and altered park ecosystems. Predicted climate change for the region may exacerbate these changes. This brief annual report summarizes some of the key findings from the 2019 field season including some species of particular interest, like big sagebrush (Artemisia tridentata), Idaho fescue (Festuca idahoensis) and cheatgrass (Bromus tectorum). A wide range of conditions and species was encountered among sampling frames. There were 78 different species recorded, with an average of 5.5 species per plot, and 29 species per frame. Big sagebrush (Artemisia tridentata) was the most abundant sagebrush, occurring in all 28 sampling frames and 62% of all plots. The most dominant shrub species was antelope bitterbrush (Purshia tridentata), being found in almost 20% of all plots, followed by prickly phlox (Leptodactylon pungens), dwarf rabbitbrush (Ericameria nana), and rubber rabbitbrush (Ericameria nauseosa). Sandberg’s bluegrass (Poa secunda), a small stature and highly resilient native perennial grass, was the most widespread and abundant native perennial grass encountered. The percentage of plots containing Sandberg’s bluegrass was 74%. Needlegrass species (Achnatherum spp.), an important native perennial grass genera, was found in 20% of the plots. Bluebunch wheatgrass (Pseudoroegneria spicata) and squirrel tail (Elymus elymoides) were found in about 15% of all plots. Thick spike wheatgrass (Elymus lanceolatus), western wheatgrass (Pascopyrum smithii), and Idaho fescue (Festuca idahoensis) were less abundant native perennial grasses encountered in many plots. Buckwheats (Eriogonum spp.), biscuit roots (Lomatium spp.), and phlox (Phlox spp.) were the most abundant native perennial forbs. All frames in CRMO had some presence of cheatgrass (Bromus tectorum) with the proportion of plots containing cheatgrass cover ranging among frames from 5-100%. Four frames had all 55 plots sampled within them containing cheatgrass. Three of these frames were located in the southern end of the park within the Wapi Flow, an area that has historically been degraded and contained higher amounts of non-native invasive species. Another four frames had 96-98% of plots containing cheatgrass. Frame 25 (Brass Cap Kipuka) and Frame 33 (south of Laidlaw) had the lowest cover with only 3 occurrences of cheatgrass each and relatively few non-native species. The Brass Cap frame has historically been in good condition, dominated by native perennial grasses and forbs. Tumble mustard (Sisymbrium altissimum) was the most common non-native invasive forb, followed by yellow salsify (Tragopogon dubius) and prickly lettuce (Lactuca serriola). There were four occurrences of rush skeletonweed (Chondrilla juncea), found in three frames, which was the only noxious weed encountered during monitoring. As one might expect, frames with high cheatgrass and non-native forb abundance showed lower native grass abundance, and vice versa.

Sagebrush steppe vegetation monitoring in Craters of the Moon National Monument and Preserve: 2019 annual report

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