Patterns and Climatic Drivers of Plant Phenology on Campus: A Case Study of Hainan University

Abstract:

The phenological patterns of plants tend to fluctuate, with variations occurring in the timing and amount of leaf-out, flowering, and fruiting from year to year or event to event. However, the phenological patterns in tropical regions are still largely unknown. The phenology of 126 plant species located in the campus of Hainan University in Haikou, Hainan Island were observed and recorded over three years, including leaf-out, flowering, and fruiting time. The main climate factors affecting plant phenology in tropical areas were analyzed by multiple regression analysis of phenology and environmental variables. The results showed that plant phenological patterns in the tropics were distinctly seasonal, leaf-out, flowering, and fruiting phenology occurred in April—June, April—August, and May—November, respectively. The climatic factors affecting the phenological pattern of leaf spreading and flowering were the average sunshine duration per month, and the number of fruit bearing species per month was correlated with air temperature, especially the number of fruit ripening species per month was significantly correlated with the monthly minimum air temperature. There were differences in the phenological periods among different functional groups. The leaf-out of shrubs was earlier than that of herbs and trees, leaf-out of wind-borne plants was earlier than that of insect-borne plants, and the leaf-out and fruit ripening time of fleshy-fruited plants were earlier than those of non-fleshy fruited plants. Bloom of trees was earlier than that of herbs and shrubs, which non-fleshy-fruited plants was earlier than fleshy-fruited plants, and fruit mature of wind-borne plants was earlier than that of insect-borne plants. These would be of great significance for predicting tropical phenological events in the future.

Key words:Plant phenology;Campus plant;Climate factor;Functional group;Tropics