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

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.

Specialization of plant–pollinator interactions increases with temperature at Mt. Kilimanjaro

“…Morphological traits were not related to the degree of species specialization, indicating that traits of one trophic level are not informative to predict specialization (Dalsgaard et al, ). Trait matching between trophic levels, in contrast, can sharpen our understanding about how species traits structure species interactions and network architecture (Albrecht et al, ; Bender et al, ; Dehling et al, ). Interestingly, we found no link between species specialization and species elevational ranges.…”

“…It is assumed that specialization in plant-pollinator networks is linked to functional traits, which restrict species flexibility to switch between different interaction partners (Dehling, Jordano, Schaefer, Böhning-Gaese, & Schleuning, 2016;Stang, Klinkhamer, Waser, Stang, & Meijden, 2009). Broad-scale correlations between specialization and species traits provide important information about such trait-based feedback on specialization, but have hardly been studied on a community level in insects (Albrecht et al, 2018;Lara-Romero et al, 2019). Bees and syrphid flies, for example, differ in their requirements for floral resources.…”

Niche width of above‐ and below‐ground organisms varied in predicting biodiversity profiling along a latitudinal gradient

“…In addition to the factors mentioned above, others may still have an impact upon a taxon's niche width and further influence biodiversity at the community level across an environmental gradient, such as biotic interactions (Albrecht et al., 2018). Natural ecosystems consist of large populations of various species whose body sizes cross several orders of magnitude and interact in ways that promote energy and substrate transformations.…”

Unravelling the history of biodiversity in mountain ranges through integrating geology and biogeography

“…providing open or closed habitats) form an important component of the paleoenvironment for animals (e.g. as food or nest resources) and thus play important roles in driving animal diversity dynamics (Albrecht et al, 2018;Fornoff, Klein, Blüthgen, & Staab, 2019). The presence of different vegetation types can be inferred from the fossil leaf and pollen record, e.g.…”