Author affiliations
1 Landscape Ecology, Institute of Terrestrial Ecosystems, Department of Environmental Systems Science, ETH Zürich, 8092 Zürich, Switzerland
2 Unit of Land Change Science, Swiss Federal Institute for Forest, Snow and Landscape Research WSL, 8903 Birmensdorf, Switzerland
3 Genetic Diversity Centre, ETH Zürich, 8092 Zürich, Switzerland
4 Functional Ecology Laboratory, Institute of Biology, University of Neuchâtel, 2000 Neuchâtel, Switzerland
E-mail addresses camille.pitteloud@usys.ethz.ch; jean-claude.walser@env.ethz.ch; patrice.descombes@wsl.ch; charles.santana@gmail.com; sergio.rasmann@unine.ch; loic.pellissier@usys.ethz.ch
Statement of authorship CP, LP and SR conceived and designed the study. CP, LP and SR wrote the manuscript text with input from all authors. CP, LP and PD contributed to data collection. CP, JCW, CNS and LP analyzed the data. All authors reviewed and contributed to the manuscript.
Keywords DNA metabarcoding, trophic network, null model, generality, robustness, nestedness, keystone species.
Type of article Ecology Letters
Short running title Elevation and trophic network structure
Counts Abstract: 142 words, main text: 5207 words, number of references: 81, number of figures: 4, number of tables: 1, number of appendices: 2
Corresponding author Camille Pitteloud, Institute of Terrestrial Ecosystems, Department of Environmental Systems Science, ETH Zürich, Universitätstrasse 16, 8092 Zürich, Switzerland; camille.pitteloud@usys.ethz.ch; +41.44.632.23.45Abstract
Ecological gradients are expected to be associated with structural rewiring of species interaction networks. The study of network structures along geographic and ecological gradients, however, remains marginal because documenting species interactions at multiple sites is a methodological challenge. Using a standardized DNA metabarcoding method applied to feces, we examined how structural properties of plant–orthoptera networks reflecting specialization and resilience vary with elevation. We found an increase in levels of generality and nestedness with decreasing temperature, and the correlation was stronger than in null models. These relationships corresponded to greater robustness and reduced importance of keystone species in alpine habitats. In cold environments, plant–herbivore networks are wired in a way that may reinforce the resilience of the system to species extinction. Documenting ecological networks along ecological gradients allows a better understanding of the influence of climate on the structure of ecosystems.