Natural History and Distribution of a High Elevation Endemic, Telesonix jamesii (Saxifragacae)

摘要

Telesonix jamesii, a rare perennial saxifrage, is restricted rocky habitats at high elevations in the southern Rocky Mountains of Colorado and New Mexico. Despite its imperiled conservation status, very little is known about the natural history of T. jamesii. We studied pollination of this species during the summers of 2019–2021 at multiple sites on Pikes Peak, CO. Here, we show that flowers of T. jamesii are visited by an unspecialized assemblage of insects and one species of hummingbird. Bumble bees (Bombus) were the most observed species visiting flowers, as well as the only group found carrying T. jamesii pollen. Our findings suggest that T. jamesii is infrequently pollinated and we infer that gene flow for this species may therefore be low. We also investigate the utility of iNaturalist data for developing SDMs for T .jamesii. Because methods for modeling rare species are limited in the literature, five different modeling techniques were considered. We found that a random forest model using ensemble training data performed the highest of any model. We then compared the performance of random forest models that use only natural history training data and those that use a combination of natural history (herbarium specimen) and iNaturalist training data. All models relied heavily on climate data (Bio9, Bio18), which indicates that this species is under threat as climate continues to change. Validation datasets affected model fits as well. Models using only herbarium data performed poorer when evaluated with cross validation than validated externally with iNaturalist data. We found that adding iNaturalist data to herbarium training data provided higher model accuracy than herbarium data alone. This study can serve as a framework for future SDM studies of species with similar data limitations.