Demography and life history of three sympatric species of Botrychium subg. Botrychium in Waterton Lakes National Park, Alberta

We followed the fate of mapped sporophytes of Botrychium paradoxum, Botrychium hesperium, and their hybrid Botrychium × watertonense in permanent plots for 6 years in Waterton Lakes National Park, Alberta. All three species had half-lives of approximately 3 years or less. Botrychium paradoxum had higher rates of recruitment and mortality leading to less stable population sizes than B. hesperium, perhaps contributing to the former's relative rarity. All species demonstrated prolonged dormancy whereby plants remain below ground for 1 or more years before reappearing. Surveys and monitoring studies for these and probably other species of Botrychium are more difficult owing to prolonged dormancy. Short lifespan and association with disturbed habitats suggests that these ferns may require natural disturbance regimes for long-term persistence.