Shifts in the timing of the early flowering in plants from a semi-arid ecoregion under climate change

Climate change has been significantly changing ecosystems. Regarding angiosperms, elevated temperature has affected the flowering time of plants across habitats, where earlier flowering was induced. The impacts of climate change on vegetation are expected to be more pronounced in dry regions because of the high irregularity in precipitation and temperature. Assessment of the effects of the long-term climate change on plants is recently possible due to the increased digitization of historical herbarium specimens. For instance, these herbarium specimens can be used to detect changes in flowering time. In this study, the shifts in flowering time of plant species collected from a semi-arid region in the western USA (the Trans-Pecos ecoregion, Texas, USA) was analyzed using a herbarium database. A total of 7163 herbarium records from 172 species were examined. Statistically significant shifts were detected in the flowering day for the early flowering stage of 19 species in the semi-arid region from 1900 to 2017. According to t-test results, 9 species delayed flowering ranging between 17 and 50 days, whereas 10 species flowering started flowering ranging from 31 to 55 days earlier ( p ≤ 0.05). Overall, these results contribute to a better understanding of the expression of plant reproductive strategies by revealing the plant responses to warming, and the ability of plants to respond climate change.