Nitrogen inputs suppress plant diversity by overriding consumer control

Anthropogenic nitrogen (N) deposition presents a global threat with significant ramifications for ecosystem functions. In terrestrial ecosystems, N-deposition is predicted to increase plant productivity but reduce diversity by bolstering dominant plants that suppress subordinate species. However, herbivores are predicted to offset these effects by consuming excess biomass produced by N-deposition. This archive contains data from a multifactorial field experiment in a grassland ecosystem showing that N-addition can actually eliminate rather than enhance top-down control by herbivores to impact plant biomass and diversity.

Methods
These data were collected in the field over three years to represent conditions in experimental nitrogen and embedded grasshopper treatments. Data are organized into four files to represent metrics related to 1) plant communities (measured in grasshopper mesocosms) 2) and 3) arthropod surveys (two separate efforts, measured in nitrogen treatment plots); and 4) traits pertinent to plants, arthropods, and their interactions (measured in nitrogen treatment plots). The sampling design varied with the variable assessed, as described in detail in the Methods section of the publication. Data are organized into four datafiles described further in the Methods and in the README tab associated with each datafile.