Phenological Patterns of Endemic Hawaiian Angiosperms.

Abstract

Studies in plant phenology have provided some of the best evidence of ecological responses to recent climate change. Many phenological studies have used herbarium specimen records for analyses. Phenology studies using herbarium records were reviewed in order to summarize approaches, applications, and validations to date. The lack of studies investigating tropical phenology was addressed by analyzing herbarium specimens from the Hawaiian Islands. The flowering and fruiting phenologies of 51 endemic Hawaiian angiosperms were analyzed using herbarium records from 1837-2015. Results indicated that 75% of these species have yearly flowering patterns. Species from temperate ancestral origins likely evolved to flower outside of spring and summer months, possibly to synchronize fruiting to the onset of the wet season. Shifts in flowering over the last century were associated with both temperature and rainfall. This study demonstrated that herbarium records can be a valuable resource for understanding the phenology of tropical plants.