Global patterns in fruiting seasons

Aim To identify geographical and climatic correlates of the timing of fruit production in fleshy fruited plant communities. Location Global. Methods We searched the literature for studies documenting monthly variation in the number of fleshy fruited species bearing ripe fruits in plant communities (i.e. fruit phenologies). From these data, we used circular vector algebra to characterize seasonal peaks in fruit production (mean date, as an angle) and the length of fruiting seasons (as a circular standard deviation). Generalized linear models and circular correlations were used to assess whether latitudinal patterns in fruit phenologies could be explained by variation in temperature, precipitation and actual evapotranspiration (AET). Results Dates of peak fruit production and the length of fruiting seasons showed consistent differences with latitude. Annual peaks in fruit production occurred 1 to 3 months after the summer solstice at high-latitude sites in both hemispheres. Fruiting seasonality increased with latitude, indicating that fruiting seasons were longer in the tropics and shorter toward the poles. AET was the best climatic predictor of fruit phenologies. Annual peaks in fruit production were positively associated with annual peaks in AET and temperature, while fruiting seasons were shorter in areas with pronounced annual variation in AET. Main conclusions Global patterns in fruiting seasons are associated with global variation in climate. Across the globe, fleshy fruits are produced after annual periods of elevated water-energy availability. Fruiting seasonality is also more pronounced in areas with strongly seasonal water-energy inputs. Therefore, the timing of reproduction in fleshy fruited plant communities appears to be determined, at least in part, by spatial and temporal variation in energy supplies needed to subsidise plant reproduction.