Habitat characteristics of Botrychium species in the Castle Region, Alberta, Canada

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Chisholm, Trinitas
McCune, Jenny L.
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Brigham Young University
ABSTRACT.—Moonwort (Botrychium Swartz) is a genus of ferns found in high diversity in the Rocky Mountains of southwestern Alberta, Canada. These small, cryptic plants are thought to prefer disturbed areas, such as trail sides. However, this idea may result from survey bias toward accessible areas near trails, or greater ease of spotting these plants in barren areas. Castle Provincial Park and Castle Wildland Provincial Park (CCWPP) are 2 recently established protected areas within this global hotspot of Botrychium diversity. Prior to 2018, provincial and international databases included only 30 records of Botrychium throughout CCWPP. Therefore, their frequency in the parks and their habitat preferences are not well understood. We used new records from the Castle region plus online herbarium records to build a genus-level species distribution model (SDM) and surveyed 24 sites of varying predicted suitability at least 100 m from trails. We then used all known records, including new records gathered during vegetation surveys, to assess habitat associations of any Botrychium species found throughout CCWPP. Botrychium occurred in a wide variety of vegetation types, with some species limited to one vegetation type. Overall, most Botrychium occurrences were on south-facing slopes, in grassland vegetation, 10–100 m away from official marked trails. We discovered 7 new occurrences in surveys at least 100 m from trails. Although 6 of the 7 new off-trail occurrences were found at sites with >40% suitability, the SDM was not a significant predictor of Botrychium occurrence. Our results show that Botrychium occurs across a wide range of vegetation types, topographic conditions, and proximity to trails and there are likely many undiscovered populations in CCWPP.
Moonworts , Botrychium Swartz , Botrychium diversity , Botrychium distribution , Castle Provincial Park , Castle Wildland Provincial Park , Castle region
Chisholm, T., & McCune, J. (2024). Habitat characteristics of Botrychium species in the Castle Region, Alberta, Canada. Western North American Naturalist, 84(1), 11-27. https://scholarsarchive.byu.edu/wnan/vol84/iss1/2