Responses of epiphytic lichens to an experimental whole-tree nitrogen-deposition gradient
2010 (English)In: New Phytologist, ISSN 0028-646X, E-ISSN 1469-8137, Vol. 188, no 4, 1075-1084 p.Article in journal (Refereed) Published
• Here, we examined the responses of the epiphytic lichens Alectoria sarmentosa and Platismatia glauca to increased atmospheric nitrogen (N) deposition in an old-growth boreal spruce forest, to assess the sensitivity of these species to N and define their critical N load. • Nitrogen deposition was simulated by irrigating 15 trees over a 3 yr period with water and isotopically labeled NH(4) NO(3) , providing N loads ranging from ambient to 50 kg N ha(-1) yr(-1) . • Thallus N concentration increased in both species with increasing N load, and uptake rates of both NH(4) (+) and NO(3) (-) were similar. Photobiont concentration increased linearly with increased N in both species, saturating in A. sarmentosa in the third year at the highest N loads (25 and 50 kg ha(-1 ) yr(-1) ). The simulated N deposition decreased the phosphorus (P) concentration in A. sarmentosa, and increased the N : P ratio in both species. • Significant responses in lichen chemistry were detected to inputs of 12.5 kg N ha(-1) yr(-1) or higher, suggesting that resources other than N limit lichens at higher N loads. However, the data also suggest that N saturation may be cumulative over time, even at low N.
Place, publisher, year, edition, pages
Wiley , 2010. Vol. 188, no 4, 1075-1084 p.
15N-labeled ammonium nitrate, Alectoria sarmentosa, Chla, critical load, lichen sensitivity, phosphorus, latismatia glauca, simulated nitrogen deposition
IdentifiersURN: urn:nbn:se:umu:diva-37620DOI: 10.1111/j.1469-8137.2010.03426.xISI: 000284074900016PubMedID: 20731782OAI: oai:DiVA.org:umu-37620DiVA: diva2:369416