Examining the Effects of Warming and Drought on Abundance and Phenology of Amorpha canescens (Leadplant)
Climate change is currently one of the world’s largest issues, as its prevalence has a negative impact on almost all areas of life. Plants play a vital role in environments, as they are a source of nutrients for many organisms and the success of ecosystems relies on their presence. Floral resources and their phenology (timing of flowering events) may be affected greatly by climate change, however, as warming can lead to shifts in floral abundance as well as shifts in their first date of flowering and times of peak flowering. Bees and flowers share an important mutualistic relationship, which these changes in floral phenology could disrupt. Previous research has found that warming significantly advanced the date of first flowering and has the potential to increase the abundance of legumes specifically, while drought has been found to reduce abundance and richness of species in some cases. However, the combination of drought and warming and its impact on floral resources and phenology is relatively unknown. In this study, the legume Amorpha canescens (leadplant) was exposed to warming, drought, and a combination of warming and drought treatments. Based on previous research, it was expected that (1) warming treatments would lead to an increase in A. canescens abundance and an earlier first date of flowering in comparison with control groups, while (2) drought treatments would lead to a decrease in floral abundance with effect on start date and peak date varying by species. Because peak flowering covaries with start date, the date of peak flowering was expected to appear sooner in warming treatments. Obtained results supported (1) and (2) regarding floral abundance, as warming treatments were found to increase abundance of flowers (F=3.65, p=0.0582) in comparison to the control group while drought was found to decrease abundance compared to the control group (not significant). Both warming and drought were found to delay the first date of flowering and date of peak flowering in comparison to the control group, however, while the combination treatment led to dates higher than but closer to the control group. These findings suggest that A. canescens may be intolerant to warming. Future efforts to plant more and conserve A. canescens will provide a positive future for the mutualistic relationship between these flowers and bees, even amidst climate change.