Phenological Responses of Forest Flora to the Changing Climate in Derived Savannas

Background and Objective: Phenological variations in plant species are one of the major indicators of climate change. This study was carried out in three forests of Eha-Alumona, Nsukka, and the changes in phenophases of plant species in the phase of the changing climatic system were ascertained. Materials and Methods: Systematic random and survey sampling designs were adopted for the study. Life forms in each quadrat were identified and assessed for phenological variations from 2018-2020. Data on the condition of the forests before the study was collected using an unstructured questionnaire. Climate elements in Nsukka from 2010-2020 were retrieved from the nearest meteorological stations. Changes in plant species phenophases over the years were compared with a t-test, while survey data was analyzed with crosstab. Trends in climatic elements were determined graphically. Results: There was a shift in the leafing periods of Melia sp. and Sterculia tragacantha, as well as in the reproductive periods of many tree species from September/October to November/December. The mean number of plants that flowered/fructified in the forests decreased in successive years, with Landolphia owariensis and Pachystela brevipes being unproductive for decades. Rainfall peaks were unimodal and tri-modal, with the onset of rainfall delayed by one month since 2016, while relative humidity decreased by 7%. There was a rise in annual mean temperature by 1°C, with a slight decrease in yearly wind speed. Conclusion: These fluctuations in the climatic system of Nsukka have affected the phenophases of plant species in these derived savanna forests.