Effects of Bird Traits on Seed Dispersal of Endangered Taxus chinensis (Pilger) Rehd. with Ex-Situ and In-Situ Conservation

Biodiversity is rapidly decreasing worldwide. Its great importance has been attached to conservation through in-situ and ex-situ management. Animal-mediated seed dispersal is an important ecological process, linking the threatened plants and animal partners in ex-situ habitats, and in turn affecting tree conservation. However, how bird traits affect seed dispersal within in-situ and ex-situ conservation still remains unclear. Here, we aim to answer this question. We tested whether bird traits affect seed deposition and seedling recruitment. Our results showed that 19 bird species foraged and removed Taxus chinensis (Pilger) Rehd. seeds across botanical gardens (ex-situ) and natural reserves (in-situ). The seed dispersal pattern of T. chinensis varied in the stages of seed removal and seed deposition, but showed no significant difference in the seedling recruitment stage. This showed that bird morphological and behavioral traits affected seed dispersal through the different contributions of varying bird species. Large birds and their high visitation frequency played a central role in seed removal patterns. The frequency of post-foraging habitat use was the most important factor determining the role of birds in seed deposition and the following seedling recruitment. Urocissa erythrorhyncha and Chloropsis hardwickii played the role of keystone species in seed deposition and seedling recruitment, respectively. Our results highlight the importance of bird traits in facilitating the seed dispersal of trees within in-situ and ex-situ conservation, which should be considered in future forest conservation and management.