Epiphyte biomonitoring for atmospheric nitrogen effects on terrestrial habitats (2nd year report)

Lewis, Jason; Leith, Ian; Wolseley, Pat; Sheppard, Lucy; Crittenden, Peter; Sutton, Mark. 2010 Epiphyte biomonitoring for atmospheric nitrogen effects on terrestrial habitats (2nd year report). SNIFFER, 39pp. (CEH Project Number: C03521) (Unpublished)

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Executive summary • This report presents the work carried out during the 2nd year of the project (June 2009-June 2010). We report on the current status of the project, present provisional analysed data (using currently available data) and outline the work plan for July 2010 - May 2011. • Twenty-eight out of the original planned 29 regional sites have been fully surveyed. The one remaining site (Halladale) has been excluded due to ongoing access permission difficulties. • All outstanding identifications (lichens and bryophytes) will be completed by end of June 2010. • Bark and branch pH’s will be completed by end of June 2010. • As only 19 of the 28 regional sites had current NH3 monitoring, 9 additional sites were set up in August 2009 at sites without current NH3 monitoring. These additional sites will be monitored until August 2010 and are operated by local conservation and regulatory agency staff. • Using combined tree species (Quercus and Betula) data, lichen species richness was found to be greater for branches compared to trunks. • Eighty-six microlichen, 67 macrolichen and 11 bryophytes and liverworts species have been identified from the 21 regional sites examined to date. • Bryophyte species richness (1-2 species) was significantly lower than that found for epiphytic lichens on both trunks and branches. • There were significant differences (p<0.001) in species richness for both micro and macrolichens between the trunks and branches. The combined mean species richness for trunks was 17 compared to 27 for branches. • For both Betula and Quercus, at least 5 trunks and 5 branches are required to be assessed at a site to give an accurate estimate of total species richness. • Greater species richness was found in the 6-10 and 11+ age classes compared to the 1-5 age class. • Mean species richness for Betula was found to be slightly greater for microlichens compared to macrolichens, whereas in Quercus the opposite was found. • There were strong logarithmic relationships between LAN scores for trunks and branches (both Betula and Quercus combined) and NH3 concentrations. The overall lichen acidophyte-nitrophyte index (LAN) was calculated for each site LAN = LA- LN where LA is the mean acidophyte score and LN is mean nitrophyte score. A change from nitrophobe to nitrophile dominance occurred at a lower NH3 concentration in the branches than trunks. This would suggest that the lichens on branches are more sensitive than those on trunks to changing NH3 concentrations. • LAN scores for trunks from 20 sites showed a strong logarithmic relationship with NH3 concentration for Betula (R2=0.874), whereas for Quercus the relationship was weaker (R2= 0.519). • A stronger linear relationship was found between LAN and substrate pH (R2=0.771) for branches than for trunks (R2=0.551). • Generally, trunk pH is more acidic than branch pH with the pH range for branches being 4.4 - 5.61 compared to the trunks 3.47 - 5.04. • Similar positive linear relationships were found between substrate pH and NH3 concentration for Quercus and Betula species i.e. R2=0.558 and R2=0.405 respectively for Quercus and Betula. • Differences were found in thalli surface pH between recognised nitrophobic and nitrophilic lichen species. These ranged from 3.56 for Hypogymnia physodes (nitrophobe) to 5.67 for the nitrophile, Xanthoria parietina. Parmelia sulcata, a neutrophile, had a mean pH of 4.39.

Item Type: Publication - Report (UNSPECIFIED)
Programmes: CEH Topics & Objectives 2009 - 2012 > Biogeochemistry > BGC Topic 1 - Monitoring and Interpretation of Biogeochemical and Climate Changes
CEH Topics & Objectives 2009 - 2012 > Biogeochemistry > BGC Topic 3 - Managing Threats to Environment and Health
CEH Sections: Billett (to November 2013)
Funders/Sponsors: Scotland and Northern Ireland Forum for Environmental Research (SNIFFER)
NORA Subject Terms: Botany
Biology and Microbiology
Ecology and Environment
Atmospheric Sciences
Date made live: 17 Feb 2011 13:44 +0 (UTC)

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