Plant community controls on short-term ecosystem nitrogen retention

Area of Science:

• Ecology
• Plant Science
• Soil Science

Background:

• Nitrogen (N) retention is a crucial ecosystem function, particularly with increasing anthropogenic N enrichment.
• Mechanisms governing N retention in grassland ecosystems are not fully understood.

Purpose of the Study:

• To investigate how plant community attributes influence nitrogen uptake and retention in temperate grasslands.
• To determine the roles of plant functional traits, diversity, and dominance in short-term N retention.

Main Methods:

• Glasshouse experiment using temperate grassland plant communities.
• Addition of a pulse of stable isotope nitrogen (15N) to track N fate.
• Measurement of plant and microbial 15N uptake and 15N leaching losses.

Main Results:

• Root biomass, herb abundance, and dominant plant traits were key drivers of N retention.
• Increased root biomass and herb abundance enhanced plant 15N uptake.
• Higher specific leaf area and root tissue density promoted microbial 15N uptake.

Conclusions:

• Dominant plant traits, rather than trait functional diversity, dictate the short-term fate of added nitrogen in the plant-soil system.
• Provides mechanistic insights into nitrogen dynamics in temperate grasslands.