New App to help us gather evidence of ozone injury on vegetation.

Visible ozone injury: Bronze stippling 

between leaf veins of Birch Betula pendula

Image: F. Hayes

A small display at last autumn's BSBI Annual Exhibition Meeting introduced 172 BSBI members to a fascinating new project set up by Katrina Sharps and colleagues from the Centre for Ecology & Hydrology (CEH). 

A new ozone smart-phone App has been developed by CEH - it allows incidences of ozone injury on vegetation to be recorded as soon as they are spotted in the field, so this summer Katrina and her team are inviting botanists to try out the App and get involved in a worldwide effort to gather evidence of ozone damage on plants.  

Visible ozone injury: Pale cream spotting on

 White clover Trifolium repens leaves

Image: F. Hayes

Katrina said "While ozone occurs naturally in our atmosphere, additional ozone is formed as a result of human activities, particularly due to vehicle and industrial emissions from fossil fuel burning. 

"Certain weather conditions (warm and sunny) can lead to “ozone episodes,” with concentrations peaking for several days at a time.

"Ozone is a very reactive gas and can negatively affect both humans and plants in a variety of ways. In humans, ozone primarily harms the respiratory system, causing irritation and inflammation in the lungs. 

"Ozone is absorbed via the leaf pores of plants, which can lead to damage in sensitive species. 

"For example, visible injury on the leaf surface, a reduction in growth (e.g. beech, birch, white clover) and reduced quality and quantity of crop yield (e.g. wheat, oilseed rape). 

The upper surface of these Wych elm Ulmus glabra 

leaves shows visible ozone injury while 

there is no damage on the underside of leaves

Image: M.J. Sanz & V. Calatayud

"The hot weather in the UK at the end of June has led to an increased concentration of ozone in our atmosphere, meaning that the coming weeks will be a good time to search for ozone damage on vegetation.

"The easiest way to detect ozone damage on plants is to look for evidence of visible injury on the leaves. 

"While symptoms can vary between plant species, there are several diagnostic features that tend to be commonly found in ozone-damaged plants: 

Visible ozone injury: Older leaves on
this Rum cherry Prunus serotina
are more damaged than younger leaves
 Image: M. Schaub

1) Small, pale yellow, cream or bronze coloured pin-head sized blotches (known as stipples) occur between the leaf veins. These spots can join up to cover large areas of the leaf when ozone levels are high; 

2) Damage appears on the upper surface of the leaves, spreading to the underside in severe cases; 

3) Older leaves (towards the base of the stem and branches) tend to be more affected than younger leaves as damage is determined by the accumulated uptake of ozone over time.

Other causes of leaf damage: Powdery mildew 

on Ash leaves Fraxinus excelsior

Image: M.J. Sanz & V. Calatayud

"It’s also important to remember that there may be other possible causes of leaf damage, for example, fungal disease, viruses or insect damage. 

"Powdery mildew can produce white areas (hyphae of the fungus) on the underside of the leaf. 

"Leaf miners (larvae of insects that eat plant tissue) can cause linear patterns of necrotic tissue, while tiny pin-head sized red-spider mites may resemble ozone stippling but can be found crawling on both sides of the leaves and are not restricted to interveinal areas.

Other causes of leaf damage: Red Spider 

mites on French bean leaves 

Phaseolus vulgaris 

Image: E. Calvo

"The ozone smart-phone App will allow the creation of a database of records from many countries. 

"Ozone pollution is a worldwide problem and there are teams of researchers investigating the negative effects of ozone on crops, trees and semi-natural vegetation worldwide, for example, in the USA, Asia (Pakistan, China, Japan, India to name a few) and across Europe.

"Before using the App for the first time, we ask participants to register (with a username and password). 

Other causes of leaf damage: Leaf miner 

trails on Beech Fagus sylvatica leaf 

Image courtesy Innes et al., 2001

"App users can then upload photographs of ozone injured plants, while coordinates for the location where the injury was detected are recorded automatically using the phone’s GPS. 

"We also ask for some further information, including choosing the broad vegetation type of the damaged plant and the species name from a list (or adding this by hand), and describing the symptoms of ozone injury (including the colour, location on the leaf and age of damaged leaves).

App screenshot #1: click to enlarge

"Questions designed to assist with quality assurance, for example, specifying any previous experience of identifying ozone damage or plant diseases and describing recent weather and ozone conditions will also be asked. For guidance, the App contains an ‘Ozone information’ section, which includes details and photographs of the key symptoms of ozone injury.

App screenshot #2: click to enlarge

"It would be very useful if people could carry out regular monitoring for ozone damage throughout the summer at a site they visit regularly, for example, a garden, park or allotment. 

"If there is no visible ozone damage on the plant, the App also allows the user to record the absence of ozone symptoms.

"We are keen to gather information on both the occurrence and lack of ozone injury symptoms under different conditions. This will help us gain a more complete understanding of the extent of the ozone problem.

App screenshot #3: click to enlarge

"The App is available to download now. For those without a smart-phone, a web-based recording facility has also been created. Both the App and web recording form are available from our website.

"We plan to use the records submitted by App participants to add to the list of ozone-sensitive species worldwide and to validate risk maps, which predict where the risk of ozone damage to vegetation is likely to be the highest. 

"As ozone damage is more likely to occur in the UK during “ozone episodes,” we will send email alerts to registered App users to let you know the best times to go and look for damage. We would like to encourage people to get involved and download the App this summer, to help us to gather as much data as possible. 

"If you think you can help, please visit our website for more information".

For further details please contact:

Dr. Katrina Sharps

Centre for Ecology & Hydrology

Environment Centre Wales

Deiniol Road, Bangor

Gwynedd LL57 2UW

Tel.: +44 (0) 1248 374500

E-mail: katshar@ceh.ac.uk

Further reading

HAYES, F., MILLS, G., HARMENS, H. & NORRIS, D. (2007) Evidence of widespread ozone damage to vegetation in Europe (1990-2006). ICP Vegetation Programme Coordination Centre, CEH Bangor, UK. (http://icpvegetation.ceh.ac.uk/publications/documents/EvidenceReportFINALPRINTEDVERSIONlow-res.pdf)

SHARPS, K., HARMENS, H., HAYES, F., MILLS, G. & SCHAUB, M. (2014) Have you seen these ozone injury symptoms? ICP Vegetation Programme Coordination Centre, CEH Bangor, UK.  (http://icpvegetation.ceh.ac.uk/publications/documents/CEHOzoneInjury_webmidres.pdf)