ICP Vegetation
International Cooperative Programme
on
Effects of Air Pollution on Natural Vegetation and
Crops
Chair:
Mr. H. Harmens
Head of Programme
Centre: Ms. G. Mills
The potential for damage to crops
by air pollution in many areas of Europe is high
and the annual economic cost may be considerable.
The programme was therefore established to consider
the underlying science for quantifying crop damage.
The objectives of ICP Vegetation
are to:
(a) evaluate the effects of air
pollutants and other stresses on crops and non-wood
plants by monitoring the onset of injury and reductions
in the yield/biomass of sensitive species;
(b) identify realistic dose-response
functions, incorporating modifying (level II)
factors for a range of economically important
crops and for crops at risk from pollution;
(c) validate and substantiate
critical levels of ozone for crops and non-wood
plants including incorporation of level II factors;
(d) facilitate the production
of European maps showing where critical levels
for ozone are exceeded;
(e) assist in assessing the economic
loss due to ozone pollution;
(f) conduct literature reviews
and specific experiments on the accumulation of
atmospheric deposition of heavy metals.
The ICP Vegetation is planned and
coordinated by a Task Force led by the United Kingdom
and supported by a coordination centre at the Centre
for Ecology and Hydrology (CEH) in Bangor, United Kingdom.
Currently 20 Parties to the Convention actively
participate the programme. Attention is focused
on ozone-induced damage to crops, as experiments
have clearly indicated that crops are sensitive
to ozone pollution. Less attention is paid to sulphur-
and nitrogen-based pollutants, as these elements
are components of fertilizers commonly used in agricultural
systems. Ozone effects are also considered for natural
and semi-natural vegetation such as grassland and
wetland communities. By concentrating on ozone,
an extensive database is being compiled for use
in the development of protocols for the control
of both ozone and nitrogen oxides. The accumulation
of atmospheric deposition of heavy metals by plants
has recently been included in ICP Vegetation work.
In the experimental programme participants
conduct a series of experiments with ozone-sensitive
species (e.g. clover) using experimental protocols
and equipment supplied by the Programme Coordination
Centre. At the end of the experimental season, participants
supply data on injury, biomass, phenological development
and biomass or yield, together with information
on climate, pollution levels, and other abiotic
factors. In some countries, supportive research
is also conducted to complement the findings of
the programme.
Experiments have evaluated the effects
of ozone on a range of crops and natural/semi-natural
vegetation species. Data on clover have been analysed
to establish two short-term critical levels of ozone
for visible injury. These consider climatic conditions
as well as ozone dose in the five days preceding
injury. ICP Vegetation participants have recorded
ozone injury on the leaves of over 20 crop species
(e.g. maize, potato, soybean, wheat) grown in commercial
fields. In 1995 and 1996 experiments were conducted
to identify other plants at risk from ozone pollution,
and injury was observed on common mallow, creeping
thistle, and broad-leaved dock.
The effects of ozone on biomass
have been determined at most ICP Vegetation sites
by comparing the biomass of ozone-sensitive and
ozone-resistant clones of white clover. An earlier
method compared the biomass of plants treated with
a chemical protectant for ozone, ethylene di-urea,
with that of untreated plants. The database generated
by these experiments has been used to validate the
long-term critical level for yield reduction and
to identify important influences on the dose response
to ozone.
Further information is available
from the Programme
Centre.