Environmental Engineering Reference
In-Depth Information
Effects and Impacts
An
environmental effect
may be considered to be any change (positive or negative)
that a project or activity may cause in the environment. Some level of environmental
effect results from almost any form of development. Small numbers of birds are
killed at Australian wind farms so these constitute effects, but
ecological impact
is
concerned with lasting detrimental change to species or populations. The premise of
legislation aimed at biodiversity protection is - or should be - to conserve viable
populations of all biota within functioning ecosystems. Ensuring this aim should be
the fundamental objective of assessments of all manner of human impacts on other
species, including those for wind energy projects.
Population Impacts
Wildlife populations are naturally regulated by births, deaths, immigration and
emigration. It is usual for populations to fluctuate to varying degrees according to
numerous variables of their environments.
Criteria for determining what might constitute a significant impact on a species
listedunderprovisionsoftheCommonwealthEPBCAct,includeonespeciically
for the wind energy sector (
EPBC Act Policy Statement 2.3 Wind Farm Industry
,
Commonwealth of Australia
2009a
). It aligns with other policies that specify crite-
ria for taxa under different categories of threat and for migratory species
(Commonwealth of Australia
2009b
,
c
,
d
). The criteria are clearly set out in terms
of effects on the viability and functioning of populations of relevant species. They
thus have a basis in the ecology, population size and conservation status of particu-
lar species.
The
EPBC Act Policy Statement 2.3 Wind Farm Industry
(Commonwealth of
Australia
2009a
) provides some explanation and examples relative to potential
effects of the wind industry. The following excerpt is useful in its indication that the
risk should be considered as proportional to the population size of particular
species:
An activity that affects, or is likely to affect, a small number of individuals usually would
not be expected to have a significant impact on the species as a whole. However, when a
species or community is in small numbers nationally, or its distribution or habitat is limited,
or if the habitat has particular importance for the species, the activity could have a signifi-
cant impact. In general, this would apply to species or communities that are most at risk of
extinction and are, as such, listed as critically endangered or endangered.
An action is likely to have a significant impact on a species listed as vulnerable where it
significantly affects an important population of that species. An example might be where a
wind farm is proposed on an island or headland, or near a wetland, that has a key breeding
population of a bird species listed as vulnerable. The breeding frequency and success rate
for that species would also be relevant considerations.
The Commonwealth guidance documents clearly indicate that significant impact
is based on the level of change that might be experienced by the populations of
