Phenological change modelling for selected Himalayan medicinal herbs using herbarium records: A case study

Abstract

Regarding the effects of warming on phenology, essentially that climate warming is advancing vegetation phenology around the globe, and case studies of specific species/regions work to gauge this impact. Thus, we attempted to demonstrate phenological patterns of selected 4 alpine/sub-alpine and 4 temperate medicinal herbs based on higher medicinal value of Indian Himalayan Region (IHR) using total 654 herbarium records and applied Generalized Additive Model (GAM) as non-normal and non-linear application. The GAM demonstrated an advancement in the flowering time for alpine/sub-alpine species (Arnebia benthamii, Meconopsis aculeata, Podophyllum hexandrum) and temperate species (Delphinium denudatum and Dioscorea deltoidea), while delayed flowering for Swertia cordata (p < 0.001). Combining the herbarium records, the model significantly projected advancement in flowering time (21–25 days) over the last 100 years only for alpine/sub-alpine species (p < 0.0001). However, the relationship between flowering time and warming winter temperature was predicted advancement in flowering time for alpine/sub-alpine species (6–10 days per 1 °C) and temperate species (8–11 days per 1 °C). The results reveal that long-term herbarium records may be considered as a useful tool for predicting the possible impact of climate change on plant phenology in the IHR using GAM approach.