High nitrogen resorption efficiency of forest mosses

Area of Science:

• Ecology
• Biogeochemistry
• Plant Physiology

Background:

• Nutrient resorption from senescing tissues is vital for plant nutrient conservation and ecosystem nutrient dynamics.
• Limited understanding of nitrogen (N) resorption and release in mosses hinders comprehension of their role in N cycling within moss-dominated ecosystems.

Purpose of the Study:

• To estimate N resorption efficiency (NRE) in two moss species.
• To identify N release pathways from mosses.
• To enhance understanding of N cycling and budgeting in mosses.

Main Methods:

• An in situ 15N tracer experiment was conducted on annual moss segments of Actinothuidium hookeri and Hylocomium splendens in old-growth fir forests.
• Nitrogen dynamics and allocation along moss segments were assessed.

Main Results:

• Nitrogen resorption efficiency (NRE) was 61% for A. hookeri and 52% for H. splendens.
• Mosses lost 23% (A. hookeri) and 33% (H. splendens) of N from live tissues via leaching.
• 15% (A. hookeri) and 14% (H. splendens) of N remained in senesced tissues (>3 years old).

Conclusions:

• Mosses act as significant nitrogen sinks, with N retention (resorption and sequestration) exceeding N loss through leaching.
• N sink strength is influenced by temperature and precipitation, factors expected to change with future climate shifts.
• Estimated NRE and leaching values can refine biogeochemical models for moss-abundant ecosystems.