Vegetation phenology can be captured with digital repeat photography and linked to variability of root nutrition in Hedysarum alpinum

Question: Can repeat (time-lapse) photography be used to detect the phenological development of a forest stand, and linked to temporal patterns in root nutrition for Hedysarum alpinum (alpine sweetvetch) an important grizzly bear food species? Location: Eastern foothills and front ranges of the Rocky Mountains in Alberta, Canada. The area contains a diverse mix of mature and young forest, wetlands and alpine habitats. Methods: We deployed six automated cameras at three locations to acquire daily photographs at the plant and forest stand scales. Plot locations were also visited on a bi-weekly basis to record the phenological stage of H. alpinum and other target plant species, as well as to collect a root sample for determination of crude protein content. Results: Repeat photography and image analysis successfully detected all key phenological events (i.e. green-up, flowering, senescence). Given the relation between phenology and root nutrition, we illustrate how camera data can be used to predict the spatial and temporal distribution and quality of a key wildlife resource. Conclusions: Repeat photography provides a cost-effective method for monitoring vegetation development, food availability, and nutritional quality at a forest stand scale. Since wildlife responds to the availability and quality of their food resources, detailed information on changes in resource availability helps with land-use management decisions and furthers our understanding of grizzly bear feeding ecology and habitat selection. Repeat photography can reliably detect the phenological development of Hedysarum alpinum, an important grizzly bear food species in the foothills and front ranges of the Rocky Mountains in Alberta, Canada. Through the relation between phenology and root nutrition, we illustrate how camera data can be used to predict the spatial and temporal distribution and quality of a key wildlife resource.