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.