The structure of plant--herbivore ecological networks varies along
elevation gradients
- Camille Pitteloud,
- Jean-Claude Walser,
- Patrice Descombes,
- Charles Novaes de Santana,
- Sergio Rasmann,
- Loïc Pellissier
Abstract
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.