The large elevation gain of 6,000 feet in the Grand Canyon supports a wide diversity of plants – around 1,700 known plant species have been identified in the park. However, only one endangered plant, the sentry milk-vetch (Astragalus cremnophylax or SMV) is found in Grand Canyon NP. This perennial herb grows within 25 feet of the rim and is only present in the cracks and crevices of the top layer. It is threatened by habitat loss, drought, competition, climate change, low reproduction rates and primarily from the activity of larger animals such as the increased population of bison in the park.
As a Botanical Resource Assistant, Sasha monitored this endangered species and collected data to further understand and prevent its decline. She recorded data on microhabitats, plant size, phenology, and the proximity of previous years’ plant locations. If new plants or seedlings were found, they were tagged for identification in future surveys and to follow their progress. Additionally, Sasha used habitat maps and GPS collar data from bison to determine if bison are impacting the SMV as well as other native plants. The seeds she gathered from wild populations of SMV and other native plants will be used for future restoration projects. Through her data collection, she found three new SMV populations and over 350 new SMV plants. However, more specifically, she found that where bison are present, fewer SMV plants were found. As bison populations increased, the SMV population decreased from 49 to 11 in the south location of the park.
While SMV is still not abundant, even with newly introduced populations, there are hopeful next steps for its recovery. This includes installing more fencing around populations, planting more SMV at reintroduction sites, and re-surveying and conducting more research. Sasha is appreciative of this opportunity to explore different fields of study and learning more about what occurs in the various parks.