Environmental Engineering Reference
In-Depth Information
engineers' as helpers and even as role models in eco-
logical design,
adaptive ecosystem management
and
restoration
and
rehabilitation
of degraded ecosystems.
(See also the work of H.T. Odum and his students,
many of whom have made great contributions to
ecological economics
, restoration and engineering.)
Ecosystem function (Ecosystem functioning)
The rate of
ecosystem processes
such as primary pro-
duction, decomposition, nutrient cycling and trans-
piration and emergent properties resulting from
species interactions such as competition, seed dis-
persal carried out by animals, and mutualistic rela-
tionships. Not to be confused with ecosystem
services. Functions, or functionality, depend on
underlying
ecosystem structure
and
ecosystem proc-
esses
and represent the potential that ecosystems
deliver
ecosystem goods and services
to humans.
Ecosystem goods and services
(EGS)
The Eco-
nomics of Ecosystems and Biodiversity (TEEB) initia-
tive defi nes ecosystem services as 'the direct and
indirect contributions of ecosystems to
human well-
being
' (de Groot
et al.
2010). Often the term ecosys-
tem services (ES) is used as shorthand for EGS. They
are made possible thanks to
ecosystem functions
and
the still deeper
ecosystem processes
and
structure
. An
alternative, and simpler, defi nition is that ecosystem
services are the transformation of a set of natural
assets (soil, plants and animals, air and water) into
things that people value (http://www.ecosystem-
servicesproject.org). However, the use of the word
'assets' here is problematic as it can lead readers to
conclude that using the term EGS automatically
leads to a commodifi cation of nature. The Millen-
nium Ecosystem Assessment (MA 2005) recognized
four categories of EGS, namely, supporting (e.g.
carbon sequestration
), regulating (e.g.
erosion
control),
provisioning (e.g. of clean water) and cultural (e.g.
spiritual and recreational needs).
Ecosystem health
The state or condition of an
eco-
system
in which its dynamic attributes are expressed
within normal ranges of activity relative to its eco-
logical stage of development (SER 2004). This meta-
phor may also include socio-economic values, such
as the function of a river system as a source of clean
water for human consumption (see Costanza
et al
.
1992 ).
Ecosystem integrity
The state or condition of an
ecosystem
that displays the
biodiversity
characteris-
tics of a
reference system
, expressed in terms of
species composition and community structure (SER
2004), or an historical range of variability. Basically
a metaphor, or umbrella term, like
ecosystem health,
and not to be confused with an attribute that can be
easily measured or monitored individually. Cf.
eco-
system stability
.
Ecosystem processes
The underlying processes of
an
ecosystem
, such as energy transfer, primary pro-
duction, food chain dynamics, hydrological path-
ways and nutrient cycling. Inextricably linked with
ecosystem structure
, but not synonymous with
eco-
system functioning
. See also de Groot
et al.
(2010) .
Ecosystem restoration
- See
ecological restoration
.
Ecosystem stability
The ability of an
ecosystem
to
maintain its given state or
trajectory
in spite of stress;
it denotes dynamic equilibrium rather than stasis.
Stability is achieved in part on the basis of an
ecosys-
tem
' s
capacity
for
resistance
and
resilience
(SER
2004 ). Cf.
ecosystem health
,
ecosystem integrity
.
Ecosystem structure
The individuals and commu-
nities of plants, animals and microorganisms of
which an
ecosystem
is composed, their age and
spatial distribution and the abiotic resources present
at a certain point in time. The elements of ecosystem
structure and fundamental
ecosystem processes
inter-
act to create
ecosystem functions
as emergent proper-
ties which in turn create the potential for the fl ow of
ecosystem goods and services
to human society.
Emerging ecosystem
A n
ecosystem
that is on the
way to becoming signifi cantly different from what it
was before due to ongoing and often unpredictable
environmental changes, caused by natural, social,
economic and cultural drivers and impacts. See
Milton
et al.
(2003) and van Andel and Aronson
(2006, chapter 16). Cf.
designer ecosystem, novel
ecosystem.
Endangered species
Biological species considered
to be in danger of extinction.
Environmental economics
Branch of neoclassical
economics that addresses environment issues such
as pollution as externalities and seeks to value
ecosys-
tem goods and services
with market values. In general,
focuses on the effi cient allocation of resources and
often fails to recognize the market as a subsystem of
'the containing and sustaining global ecosystem'
(Daly & Farley 2010). Cf.
ecological economics
.
Environmental gradient
A local or regional
change in environmental conditions, for example
moisture, elevation, altitude or soil type. The gradi-
ent can be narrow or diffuse, and is often expressed
in the
zonation
of a
community
.
