Bulbuls and crows provide complementary seed dispersal for China’s endangered trees

Abstract

Background: Different functional frugivores generally exhibit unequal contributions, both in terms of quantity (seed removal) and quality (seedling recruitment), to effective seed dispersal of plant species. However, variations in this dispersal pattern generated by frugivores across different regions are still unknown. Methods:In our study, we evaluated the contributions of two functional frugivore bird groups, the bulbuls (Pycnonotidae) and crows (Corvidae), in both the seed removal and seedling recruitment of the endangered Chinese yew tree (Taxus chinensis) across three different geographical regions in eastern China. Results:The dominant crow species, Urocissa erythrorhyncha, was the most common disperser crow species at all sites, while the dominant bulbul species varied across the three sites. Furthermore, the two functional groups of dispersers diverged in the aspects of seed removal (quantity) and seedling recruitment pattern (quality). While bulbuls outperformed crows in seed removal (quantity), crows took more seeds to a safer site for seedlings (quality). Conclusions:Our results highlight the importance of variations in the effective seed dispersal patterns of different functional disperser groups across different regions in the conservation and management of endangered tree species.

Beyond Scatter-Hoarding and Frugivory: European Corvids as Overlooked Vectors for a Broad Range of Plants

“…Heintze's work shows that corvids disperse a broad taxonomic and ecological range of plants through gut passage, and slightly more than half of the taxa are dispersed by nonclassical endozoochory (i.e., through granivory). The importance of classical endozoochory by corvids has adequately been demonstrated by much contemporary research (Nogales et al, 1999;Wenny et al, 2016;Bai et al, 2017). Heintze (1918, p. 29) also wrote: "Magpies, Hooded Crows, Carrion Crows, Rooks, Jackdaws, Ravens, Choughs, Yellow-billed Choughs, and Siberian Jays disperse seeds of pretty much all European trees, bushes, shrubs, and herbs with berries [fleshy fruits]."…”

Importance of plant and fruit traits on the structure of bird seed dispersal networks in different disturbed habitats

“…Previous research has demonstrated that the dominant bird species in a network are strongly influenced by their relative abundance and their ability to adapt to different habitats (Muñoz et al 2017;Schupp et al 2017). In the disturbed habitats of this study, bulbul species were abundant and exhibited a generalist behavior in their habitat selection, which likely contributed to their importance in the seed dispersal networks (Bai et al 2017). Furthermore, the study also highlighted the significance of plant species in seed dispersal networks, which are influenced by the availability and characteristics of their fruits.…”

“…In the disturbed habitats of this study, bulbul species were abundant and exhibited a generalist behavior in their habitat selection, which likely contributed to their importance in the seed dispersal networks (Bai et al. 2017). Furthermore, the study also highlighted the significance of plant species in seed dispersal networks, which are influenced by the availability and characteristics of their fruits.…”

Bird functional traits affect seed dispersal patterns of China’s endangered trees across different disturbed habitats

“…In Asia, many natural forests have been transformed to farmlands by local residents, resulting in several natural patches of forest within highly human-disturbed habitats (Foley et al 2005;Haddad et al 2015). Therefore, it is important to understand the effects of land-cover change on plant regeneration in these disturbed habitats (Cordeiro and Howe 2003;Markl et al 2012;Bai et al 2017).…”