Nitrogen is one of the five major chemical elements essential for life. Most
living organisms can only make use of reactive nitrogen, which includes
inorganic forms of nitrogen like ammonium, ammonia, nitrate, nitrous oxide,
nitric acid and nitrogen oxide, and organic compounds like urea, proteins,
amines and nucleic acids.
Human activity has dramatically altered the nitrogen balance, by releasing
reactive forms into the environment. Increased levels of reactive nitrogen have
resulted from cultivating legumes, rice and other crops that promote nitrogen
fixation, by transforming nitrogen to ammonia to sustain food production and
some industrial process, and by burning fossil fuels.
Reactive nitrogen can significantly damage environmental systems, which in tern
can negatively affect human health. Reactive nitrogen is implicated in the
eutrophication of coastal ecosystems, the acidification of forests, soils, and
freshwater streams and lakes, the high concentration of ozone in the lower
atmosphere and losses of biodiversity.
Trends in the deposition of nitrogen, and the subsequent response of ecosystems
to this deposition, can be used as an indicator of threats to biodiversity and
ecosystem health. The concept of critical loads and what happens when they are
exceeded is already used in Europe as an indicator for quantifying the response
of ecosystems. Trends in nitrogen deposition, and ecosystems’ response to it,
will be available on the global scale by 2010.
Invasive alien species (IAS) are one of the key threats to biodiversity and cost
society billions of dollars. It is therefore essential that their numbers and
spread, as well as their impacts on native populations, are monitored.
Several countries have ongoing, systematic monitoring programmes for invasive
alien species, and various single indicators, largely focussing on the number of
IAS, have been developed and applied at country and regional level. This
indicator will incorporate information from a number of national and regional
databases to show trends in IAS across the globe. This will be facilitated by
the development of the
Global Invasive Species Information Network (GISIN), which will provide a
platform through which IAS information and data can be accessed. Data may also
be obtained from the IUCN Red List, which records the primary threats to species
including the impacts of IAS. Several trends in IAS will be identified by 2010.