ILCD Handbook: Framework and requirements for LCIA models and ...

ILCD Handbook: Framework and requirements for LCIA models and indicators First edition
concept. For biodiversity, the species-diversity oriented PDF-concept is seen as the only
really operational concept among those investigated, integrating the potentially lost fraction
of natural species over area and time.
3.2.2 Background and Discussion
The Area of Protection ‗Natural Environment‘ (or Ecosystem Health), encompasses the
natural ecosystems globally, in terms of their function and structure. It ought to be noted that
the resource aspect of ecosystems (biological renewable resources, and managed, manmade
ecosystems like plantations or agricultural fields) is addressed under the AoP ‗Natural
Resources‘ and not included here. For Natural Environment, the aim is to quantify the
negative 11 effects on the function and structure of natural ecosystems as a consequence of
exposure to chemicals or physical interventions 12 .
The complexity of the natural ecosystems with their multiple interactions between different
populations at the same or different trophic levels, and the physical and chemical
surroundings makes it a challenging task to assess effects on their structure and functions. In
ecotoxicology, this task has typically been addressed by focusing on the occurrence of
different species in the ecosystem, i.e. the biodiversity.
―Biodiversity can be defined at different levels: ecological diversity (ecosystems),
population diversity (species) and genetic diversity (genes). This grouping is reflected in the
Rio Convention‘s definition of biodiversity as ―the variability among all living organisms from
all sources, including inter alia, terrestrial, marine and other aquatic ecosystems and
ecological complexes of which they are part; this includes diversity within species, between
species and of ecosystems” (EEA, 1997).
“Biodiversity, which is an indicator of the ecosystem structure, does not automatically
reflect the natural environment (Forbes and Forbes 1993; Tillman 2001). This is due to the
fact that the integrity of ecosystems depends not only on species richness (and other
structure related properties, e.g. number of trophic levels) but also on the protection of the
function of the ecosystem (e.g. biomass production and nutrient cycling). If for example a
chemical stress is targeted at a single species but this species is a keystone species on
which the function of the ecosystem heavily relies, the function of the ecosystem may
undergo major changes,” 13 whereas other species may exert functions which are easily taken
over by other species, should this species disappear (Mooney et al., 1995).
When modelling damage to natural ecosystems, biodiversity is thus not the only possible
endpoint. Function-related parameters like biomass production or mineralisation might
represent better the functional performance of the ecosystem and, in some cases, might be a
more relevant endpoint indicator, depending on which properties of the AoP are deemed
worthy of protection 14 . Recreative value may thus be better represented by a biodiversity
indicator, whereas production value and life support functions may be better represented by
11 All impacts on the environment are considered as negative in the sense of being undesirable. To the
extent that the product system, which is the object of the LCA, has positive impacts on the
environment (e.g. wastewater treatment), this is quantified in the inventory analysis.
12 The following midpoint impacts are considered to contribute to damages on Natural Environment,
although the contribution has not for all of them been modelled by recommended methods: climate
change, ozone depletion, photochemical ozone formation, ionising radiation, acidification,
eutrophication, ecotoxicity, land use, desiccation and salination.
13 From J. Payet & H.F. Larsen, Damage modelling for Life Cycle Impact Assessment on Ecosystems;
Report- Swiss National Fund and Ecole Polytechnique Fédérale de Lausanne; November 2002 (13p.).
14 The health of Earth ecosystems and the role of ecosystem function for quality of human life is
investigated and extensively discussed in the Millenium Ecosystem Assessment – see
http://www.millenniumassessment.org/en/index.aspx
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