Bryophyte physiological responses to, and recovery from, long-term nitrogen deposition and phosphorus fertilisation in acidic grassland
Article first published online: 17 SEP 2008
© The Authors (2008). Journal compilation © New Phytologist (2008)
Volume 180, Issue 4, pages 864–874, December 2008
How to Cite
Arróniz-Crespo, M., Leake, J. R., Horton, P. and Phoenix, G. K. (2008), Bryophyte physiological responses to, and recovery from, long-term nitrogen deposition and phosphorus fertilisation in acidic grassland. New Phytologist, 180: 864–874. doi: 10.1111/j.1469-8137.2008.02617.x
- Issue published online: 6 NOV 2008
- Article first published online: 17 SEP 2008
- Received: 23 May 2008; Accepted: 18 July 2008
- chlorophyll fluorescence;
- nitrate reductase;
- nitrogen deposition;
- P limitation;
- Pseudoscleropodium purum;
- Rhytidiadelphus squarrosus
- • Atmospheric nitrogen deposition can cause major declines in bryophyte abundance yet the physiological basis for such declines is not fully understood. Bryophyte physiological responses may also be sensitive bioindicators of both the impacts of, and recovery from, N deposition.
- • Here, responses of tissue nutrients (nitrogen (N), phosphorus (P) and potassium (K): NPK), N and P metabolism enzymes (nitrate reductase and phosphomonoesterase), photosynthetic pigments, chlorophyll fluorescence, sclerophylly and percentage cover of two common bryophytes (Pseudoscleropodium purum and Rhytidiadelphus squarrosus) to long-term (11 yr) enhanced N deposition (+3.5 and +14 g N m−2 yr−1) are reported in factorial combination with P addition. Recovery of responses 22 months after treatment cessation were also assessed.
- • Enhanced N deposition caused up to 90% loss of bryophyte cover but no recovery was observed. Phosphomonoesterase activity and tissue N : P ratios increased up to threefold in response to N loading and showed clear recovery, particularly in P. purum. Smaller responses and recovery were also seen in all chlorophyll fluorescence measurements and altered photosynthetic pigment composition.
- • The P limitation of growth appears to be a key mechanism driving bryophyte loss along with damage to photosystem II. Physiological measurements are more sensitive than measurements of abundance as bioindicators of N deposition impact and of recovery in particular.