Effects of plant species richness on the structure of plant-bird interaction networks along a 3000-m elevational gradient in subtropical forests

Background

The structure and diversity of ecological communities is shaped by symbiotic plant and animal relationships. Some birds feed on fleshy fruit producing plants to disperse seeds and facilitate plant reproduction. Bird seed-dispersal networks are plant-animal assemblages that change with environmental conditions. Species richness and species specialization interact with elevation to result in unique assemblages. In this study, the authors examine how plant and bird interactions change with plant species richness along a 3000-meter gradient in a subtropical forest in China.

Research Goals and Methods

This study aims to test the effects of elevation on bird-plant assemblages at both a species and network level. The authors hypothesize that as elevation increases, diversity interaction patterns will decrease and specialization will increase at a network level. Also, the number of partnerships of both plants and animals will decrease at a species level. Finally, the number of specialists and the degree of specialization of species will decrease. Authors predict woody plant species richness will also impact plant and bird partnerships. The study is conducted in the Shennongjia National Park at an elevation between 400 to 3000 meters. Each site is placed in a category of elevation and sites had varying numbers of plots. Within the plots researchers recorded bird-plant interactions such as fruit eating, woody plant species, and bird species. 

Conclusions and Takeaways

Elevation has a significant impact on bird-plant interactions at the species and network levels. In general, as elevation increases, species diversity decreases and bird-plant interactions become fewer and more specialized. The results of this study provide evidence for the value of biodiversity protection in subtropical forested regions. The authors recognize this study as the first empirical evidence that elevation and plant species richness have a significant impact on plant-bird interactions in subtropical forests. Further studies are recommended to better understand the nuances of these interactions so that better management practices may be implemented.