Ecosystem nitrogen retention is regulated by plant community trait interactions with nutrient status in an alpine meadow

1.Biotic nitrogen (N) retention is an important ecosystem function in the context of ongoing land use intensification, N deposition and global warming. However, a paucity of experimental evidence limits understanding of how different plant community components influence N retention in terrestrial ecosystems.

2.In this investigation we conducted a 15N labelling experiment to test how plant community properties, including plant species richness/diversity, dominance and functional traits, influence plant N uptake and retention under different nutrient availabilities. A three-year experiment examined the effects of adding N (10 g N m−2 year−1) and phosphorus (P) (5 g P m−2 year−1) to an alpine meadow on the Qinghai-Tibetan Plateau.

3.Results show that 15N retention increased with the addition of N and P; the addition of P produced the largest increase of 15N retention in plant and soil N pools. Changes in soil nutrient conditions also facilitated different plant community controls on ...