Differences in the fruit removal patterns of Cleyera japonica by frugivorous birds in two forest stands at different developmental stages in a warm‐temperate region

Abstract

AbstractWe investigated the fruit removal patterns of Cleyera japonica by frugivorous birds in two adjacent forest stands at different developmental stages due to secondary succession (a secondary deciduous forest stand, and an evergreen forest stand where evergreen oak is the dominant species) in a warm‐temperate region in western Japan. The fruit removal rate was significantly higher in the evergreen forest stand than in the deciduous forest stand, whereas the abundance of C. japonica fruits and that of all fleshy‐fruited woody species did not positively affect the fruit removal. However, the Cox proportional‐hazards model with mixed effects, using data concerning the disappearing patterns of mature fruits from twigs, implied that the fruit removal of C. japonica by birds within the crown was not significantly different from that between the stands. The timing of seed dispersal of C. japonica was prolonged in the evergreen forest stand compared with that in the deciduous forest stand. In the evergreen forest stand, considerable numbers of seeds were found in seed traps after early January, when almost all the fruits had disappeared from the crown. In the evergreen forest stand, we constantly observed gulpers that are assumed to forage C. japonica fruits frequently on the ground. These results suggested that the differences in the structural attributes between the forest stands influence the bird assemblage and their foraging patterns, which would lead to changes in the fruit removal patterns of C. japonica with the shift of forest stands due to secondary succession.