Functional importance of bird-dispersed habitat for the early recruitment of Taxus chinensis in a fragmented forest

Abstract

The relationship between bird habitat selection and seed deposition is well established; however, knowledge remains limited on the functional importance of bird habitat for the early recruitment of seed deposition and seedlings in remnant fragmented forests. Here, we evaluated the post-foraging habitat use by birds and quantified the effects of habitat factors on seed deposition and seedling distribution of the endangered Chinese yew Taxus chinensis in a fragmented forest. Birds preferentially frequented fruiting trees for perching (85%, T. Chinensis and Machilus thunbergii trees). Tree cover, height, crown size, and girth were the most important factors affecting habitat use by birds. Consequently, the number of deposited seeds was positively affected by three tree-associated perching traits (girth, cover, and crown size). Seedling distribution strongly overlapped with the distribution of deposited seeds, confirming that seedlings could survive in bird-dispersed habitats. Increasing tree girth, cover, and crown size may enhance seedling recruitment. Our results highlighted the functional importance of large trees in patchy environments for supplying suitable sites for bird habitat use, which also fitted the requirement for early recruitment of T. chinensis. Consequently, protecting remaining large trees in fragmented forests should be considered in forest conservation and management.