Plant and animal functional diversity drive mutualistic network assembly across an elevational gradient

Jörg Albrecht,Andreas Hemp,Kim M Howell,Thomas Nauss,Marco Tschapka,Maximilian G R Vollstädt,Marcell K Peters,Hamadi I Dulle,David Schellenberger Costa,Alice Classen,Michael Kleyer,Antonia Mayr,Matthias Schleuning,Markus Fischer,Ingolf Steffan-Dewenter,Neduvoto P Mollel,Katrin Böhning-Gaese

doi:10.1038/s41467-018-05610-w

Abstract

Species’ functional traits set the blueprint for pair-wise interactions in ecological networks. Yet, it is unknown to what extent the functional diversity of plant and animal communities controls network assembly along environmental gradients in real-world ecosystems. Here we address this question with a unique dataset of mutualistic bird–fruit, bird–flower and insect–flower interaction networks and associated functional traits of 200 plant and 282 animal species sampled along broad climate and land-use gradients on Mt. Kilimanjaro. We show that plant functional diversity is mainly limited by precipitation, while animal functional diversity is primarily limited by temperature. Furthermore, shifts in plant and animal functional diversity along the elevational gradient control the niche breadth and partitioning of the respective other trophic level. These findings reveal that climatic constraints on the functional diversity of either plants or animals determine the relative importance of bottom-up and top-down control in plant–animal interaction networks.

Highlights

Species’ functional traits set the blueprint for pair-wise interactions in ecological networks
The functional traits that regulate species interactions can be viewed as coexistence traits that govern niche breadth and niche partitioning in complex ecological networks and determine the ecosystem functions derived from ecological communities[4,5,6]
To address these two questions, we recorded a unique dataset of mutualistic bird–fruit, bird–flower and insect–flower interaction networks and associated functional traits along a 3.5 km elevational gradient (872–4396 m above sea level [a.s.l.]) of near-natural and a Animal interaction niche

Summary

Introduction

Species’ functional traits set the blueprint for pair-wise interactions in ecological networks. Shifts in plant and animal functional diversity along the elevational gradient control the niche breadth and partitioning of the respective other trophic level These findings reveal that climatic constraints on the functional diversity of either plants or animals determine the relative importance of bottom-up and topdown control in plant–animal interaction networks. We ask whether trait matching is a general phenomenon across mutualistic networks and whether bottom-up and topdown forces simultaneously control the assembly of these networks in real-world ecosystems To address these two questions, we recorded a unique dataset of mutualistic bird–fruit, bird–flower and insect–flower interaction networks and associated functional traits along a 3.5 km elevational gradient (872–4396 m above sea level [a.s.l.]) of near-natural and a Animal interaction niche

Methods

Results

Conclusion