NH3 concentrations below the current critical level affect the epiphytic macrolichen communities – evidence from a northern European city

Manninen, Sirkku; Jääskeläinen, Kimmo; Stephens, Amy; Iwanicka, Agata; Tang, Sim ORCID:; van Dijk, Netty. 2023 NH3 concentrations below the current critical level affect the epiphytic macrolichen communities – evidence from a northern European city. Science of the Total Environment, 877, 162877. 11, pp.

Before downloading, please read NORA policies.
N535514JA.pdf - Published Version
Available under License Creative Commons Attribution 4.0.

Download (2MB) | Preview


Acidophytic, oligotrophic lichens on tree trunks are widely considered to be the most sensitive biota to elevated concentrations of atmospheric ammonia (NH3). We studied the relationships between measured NH3 concentrations and the composition of macrolichen communities on the acidic bark of Pinus sylvestris and Quercus robur and the base-rich bark of Acer platanoides and Ulmus glabra at ten roadside and ten non-roadside sites in Helsinki, Finland. NH3 and nitrogen dioxide (NO2) concentrations were higher at the roadside than non-roadside sites indicating traffic as the main source of NH3 and nitrogen oxides (NOx). The diversity of oligotrophs on Quercus was lower at the roadside than non-roadside sites, while that of eutrophs was higher. The abundance and presence of oligotrophic acidophytes (e.g., Hypogymnia physodes) decreased with increasing NH3 concentration (2-year means = 0.15–1.03 μg m−3) especially on Q. robur, while those of eutrophic/nitrophilous species (e.g., Melanohalea exasperatula, Physcia tenella) increased. The abundance of some nitrophytes seemed to depend only on bark pH, i.e., their abundances were highest on Ulmus, which had the highest average bark pH. Overall, the results of lichen bioindicator studies may depend on tree species (bark pH) and lichen species used in calculating indices describing the air quality impact. Nevertheless, Quercus is recommended to be used to study the impact of NH3 alone and in combination with NOx on lichen communities, because the responses of both oligotrophic acidophytes and eutrophic species can already be observed at NH3 concentrations below the current critical level.

Item Type: Publication - Article
Digital Object Identifier (DOI):
UKCEH and CEH Sections/Science Areas: Atmospheric Chemistry and Effects (Science Area 2017-)
UKCEH Fellows
ISSN: 0048-9697
Additional Information. Not used in RCUK Gateway to Research.: Open Access paper - full text available via Official URL link.
Additional Keywords: ammonia, acidophytes, nitrophytes, nitrogen dioxide, bark pH, roadside
NORA Subject Terms: Ecology and Environment
Biology and Microbiology
Date made live: 06 Nov 2023 11:07 +0 (UTC)

Actions (login required)

View Item View Item

Document Downloads

Downloads for past 30 days

Downloads per month over past year

More statistics for this item...