Effects of Nitrogen Enrichment on the Competition Network of
Above-Ground Species in Inner Mongolia Steppe
Abstract
Nitrogen enrichment affects and changes the community structure of
terrestrial ecosystems. Recently, intransitivity competition networks
have been widely considered to in maintaining coexistence and
biodiversity. However, whether the structure and function of the species
competition network changes under nitrogen enrichment remains unclear.
In this paper, we applied the Apriori algorithm to find dominant species
assemblies to simulate competition matrices. We found that (1)
intransitive competition networks derived by a species-dominant assembly
accounted for a relatively large proportion of the derived networks, and
the species acting as mediators constituted a nested pattern; (2)Under N
enrichment, the complexity of the networks varied from an intransitive
network to a sub-competition structure, and transitive networks was a
transition structure between these two structures; (3) the negative
effect of N-enrichment on species network was counteracted by mowing and
rainfall; and (4) increasing the number of loops enhances the diversity
in a community, while high competition among species is a representation
of an intransitive competition network.