Environmental Engineering Reference
In-Depth Information
D e fi nition of Terms
There are many different terms and defi nitions used around the world describing
introduced species and their impacts and there is no common agreement in the sci-
entifi c community or embedded in regulative/management/policy. The following
paragraphs defi ne some of the key terms used in this chapter.
Non-indigenous species are species, or other viable biological substances, that
entered an ecosystem beyond its historical known range, including all organisms
that have been transferred from one country to another, this includes invasive species,
i.e., species causing economic or environmental harm or harm to human health
(ANS Task Force
1999
). A similar defi nition refers to non-indigenous species as
any individual, group, or population of a species, or other viable biological material,
that is intentionally or unintentionally moved by human activities beyond its natural
range or natural zone of potential dispersal, including moves from one continent or
country into another and moves within a country or region; including all domesti-
cated and feral species, and all hybrids except for naturally occurring crosses
between indigenous species. Synonyms: alien, immigrant, introduced, and non-
native (EPA
2001
). The IMO Guidelines G7 (IMO
2007
) defi nes non-indigenous
species as “… any species outside its native range, whether transported intention-
ally or accidentally by humans or transported through natural processes.” This defi -
nition goes further compared to the previous ones as it includes natural transport
processes while other defi nitions limit non-indigenous species to human-mediated
species movements. It should also be noted that not all non-indigenous species are
negatively impacting in the receiving environment.
The negatively impacting species, which are termed invasive species, i.e., are
those species which threaten the diversity or abundance of native species; the eco-
logical stability of infested ecosystems; economic (e.g., agricultural, aquacultural,
commercial, or recreational) activities dependent on these ecosystems; and/or
human health. Synonyms include harmful, injurious, invader, noxious, nuisance,
pest, and weed (EPA
2001
). As per this defi nition invasive species could be either
native (see outbreak forming species below), cryptogenic or non-indigenous spe-
cies. A second defi nition addresses invasive alien species (IAS, based on Olenin
et al.
2010
) as a subset of established non-indigenous species, which have spread,
are spreading or have demonstrated their potential to spread elsewhere and have an
adverse effect on one or more of the following: biological diversity, ecosystem func-
tioning, socio-economic values or human health in invaded regions. However, there
are also native species which cause concern which becomes in many cases clear
when they occur in higher densities, examples include outbreaks of native jellyfi sh
or mass developments of native harmful algae (outbreak forming species).
The term Harmful Aquatic Organisms and Pathogens (HAOP) appears in the
IMO Ballast Water Management Convention (BWM Convention) and defi nes it as
being any aquatic organisms or pathogens, which, if introduced into the sea includ-
ing estuaries, or into fresh water courses, may create hazards to the environment,
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