Routes to Clean Air 2019 Joint Nature Conservation Committee

1. The right evidence for the job
Data and uncertainty in ecological assessment of
air pollution
Susan Zappala; Susan.Zappala@jncc.gov.uk
Routes to Clean Air 2019; IAQM

2. Overview
• JNCC’s role
• Risk to UK ecosystems from air pollution
• Assessing these effects
• Data and evidence
• Uncertainty
• Examples of ecosystem effects
• From the literature
• In the field
• UK Projects to address these issues

3. JNCC’s Role
• Provide evidence and advice on, e.g.:
• air pollution impacts on the natural environment;
• monitoring and assessing impacts;
• links between biodiversity and air quality policy; and
• research requirements.
• Site condition guidance
• UK co-ordination (eg Inter-agency Air Pollution Group)
• International collaboration

4. Air Pollution Effects on Ecosystems
N Critical load exceedance
SACs (2015-2017)
SAC A/SSSI
England 94.9 87.1
Wales 94.9 97.7
Scotland 80.6 72.9
NI 98.0 87.2
UK 89.7 85.8
Percentage of sites with
nutrient N CL exceedance
2015-2017
NH3 Critical level
exceedance (2014-16)
Rowe et al 2019 - Defra Critical Load Exceedance Trends Report
Exceedance (µg m-3)
No Exceedance
Lower plant critical level
Higher plant critical level

5. Assessment Data
Assessment
decision
Habitat
Sensitivity
(Benchmarks)
Conservation
Objectives
Ecological
monitoring
data
Predicted
magnitude of
change from
proposal Background
Air Quality
Historical
pollution
Confounding
factors

6. Challenges for Interpreting
Assessment Data
• Data availability
• Data applicability
• Model uncertainty
• Other pollutions
sources and
confounding factors
• Cumulative/ additive
emission source
effects
• Country-specific
requirements
Reasonable
Scientific Doubt
Data availability
and applicability
Nationally
applicable, Publicly
available data
Site specific,
Variable availability
Highly specific,
limited availability
National evidence/
modelling
Site specific
monitoring data
Detailed study data

7. Identifying Issues:
Common Indicators of nitrogen deposition effects
Response variable Acid
grassland
Bog Upland
heath
Lowland
heath
Sand
dunes
Species composition     
Total species richness     
Bryophyte species
richness

Lichen species richness  
Forb species richness  
Graminoid species
richness
 
Caporn et al 2016; NECR210

8. Relating air quality to
ecosystem damage: Lichen
Bosanquet 2019; Transect studies; Natural Resources Wales Report 298
Nitrogen sensitive Usnea and Evernia
Centre of Dinefwr Deer Park
Nitrogen tolerant Xanthoria
Gelli-aur College Farm (ca 3.5km)

9. Acute Effects: Lower Plants
Images: Áine O’Reilly, NIEA/DAERA 2019
Healthy Sphagnum Impacted Sphagnum
Ammonia 8 to14 µg m-3
Ballynahone Bog, Northern Ireland
Pinking of Cladonia
Ammonia 8 µg m-3

10. Acute Effects: Higher Plants
Áine O’Reilly, NIEA/DAERA 2019
Algae on Heather
Ammonia 8 to14 µg m-3
Ballynahone Bog,
Northern Ireland
Algal Slime on Trees
Ammonia 33 µg m-3
Moninea Bog,
Northern Ireland
Sutton 2007; Moninea Bog Assessment

11. Long-term Effects: Habitat
Increasing N deposition correlated with reductions in
species richness and changes in species composition
Caporn et al 2016; NECR210

12. Longterm Effects: Habitat
• Response of species
richness of N
deposition is curved for
many habitats.
• Bogs do not have
curvilinear response
• Sharp losses below
lower end of habitat
specific critical load.
• Losses continue
beyond upper end of
critical load range.
Caporn et al 2016; NECR210

13. Longterm Effects: Habitat
Control
8 kg N ha-1 y-1
Whim Bog, Scotland; Wet deposition nutrient experiment
with thanks to Netty van Dyjk for experiment data; Images Susan Zappala 2019
Nitrate plus PK
32 kg N ha-1 y-1
Ammonia plus PK
64 kg N ha-1 y-1

14. Indirect Effects
• Effects on feeding and
breeding habitat
• Reduced quality of
larval food
• Increased frost damage
• Increased sensitivity to
other factors
• Climate change
• Temperature
• Drought
www.apis.ac.uk; Calluna frost damage
Allan Drewitt 2014; High Brown Fritillary Butterfly

15. Including uncertainty: NDF
Jones et al 2016; JNCC report 579: Nitrogen Decision Framework

16. Nitrogen Decision Framework
Jones et al 2016; JNCC report 579: Nitrogen Decision Framework

17. Uncertainty and
Exceedance
Jones et al 2016; JNCC report 579: Nitrogen Decision Framework

18. Looking forward
• Air Pollution Information System (www.apis.ac.uk)
• Review of ecosystem effects gallery
• Nitrogen Decision Framework pilots and evaluations
• Towards the development of a Nitrogen Deposition Framework for vegetation
assessment in Scotland.
• Strategic thinking
• Northern Ireland Making Ammonia Visible
• Clean Air for Scotland Review
• Clean Air Zone Framework for Wales programme
• Defra Clean Air Strategy (England)
• New techniques
• Earth observation data, UAVs, meta-analyses
• Improved habitat mapping
• Data portals

19. Stay connected
• www.jncc.gov.uk
www.linkedin.com/company/jncc
www.facebook.com/JNCCUK
twitter.com/JNCC_UK
• Susan.Zappala@jncc.gov.uk