Environmental Engineering Reference
In-Depth Information
when returning an ecosystem to a former 'pre-dis-
turbance' state or
trajectory
is not possible, or desir-
able, rehabilitation is often the best option.
Reinforcement
The process of strengthening a
small and vulnerable population of a plant or animal
species in situ. Cf.
reintroduction.
Reintroduction
The intentional introduction of a
plant or animal species in an
ecosystem
from which
it has been extirpated or in areas where it is consid-
ered threatened or vulnerable. Cf.
reinforcement.
Resilience
There are many different defi nitions of
'resilience' (see e.g. Gunderson 2000). In this topic,
we follow Hollings (1973): resilience is the capacity
of an ecosystem to tolerate a
disturbance factor
and
recover autonomously by natural regeneration
without collapsing or shifting into a qualitatively dif-
ferent state controlled by a different set of processes.
Westman (1978) offered a simpler defi nition which
is also relevant to restoration: the ability of an
ecosystem to recover from
disturbance
(or better:
de-
gradation
) without human intervention. This is
sometimes called '
ecological resilience
'. Other authors
(e.g. Pimm 1991) have put emphasis on another
aspect of resilience, that is, the return time to the
previous steady state, currently called 'engineering
resilience'. According to an alternative defi nition
(see Brand & Jax 2007) that more or less subsumes
the notion of
resistance
(
sensu
Westman 1978 ), a
resilient ecosystem can withstand shocks and rebuild
itself, or persist on a given developmental trajectory
or within a given confi guration of states (sometimes
called a regime) in systems where multiple regimes
are possible (Walker & Salt 2006). Resilience in
social or
socio - ecological systems
depends in large part
on the capacity of humans to anticipate and plan
intelligently for the future.
Resistance
The capacity of an
ecosystem
to main-
tain its steady state in response to one or more
dis-
turbance factors
.
Restoration -
See
ecological restoration.
Restoration ecology
The study of ecological resto-
ration, for which practice it attempts to provide
concepts, theories, models, methodologies and tech-
nical, biological and ecological information for use
by practitioners. Concurrently, the science that
advances the frontiers of theoretical ecology through
studies of restored
ecosystems
and those that are
undergoing restoration.
Restoration of Natural Capital (RNC)
Invest-
ment in
su stainability
of both natural and human-managed
ecosystems, while contributing to the socio-economic
well-being of people (see
human well - being
). Renew-
able, replenishable and cultivated natural capital
delivers
ecosystems goods and services
; RNC is required
when delivery is interrupted or impeded. RNC
includes the
ecological restoration
or
rehabilitation
of
ecosystems
, ecologically sound improvements
to
production systems
, ecologically sound improve-
ments in the extraction, transport, processing and
utilization of biological resources, or nonrenewable
natural capital, and efforts to increase public aware-
ness and appreciation of the importance of
natural
capital
.
Revegetation
Establishment of plant cover on open
land, often with one or few species, irrespective of
their origin or
provenance
. See also
reforestation
.
Runoff
Rainfall or other water that moves towards
lower elevations by spreading across the land
surface, rather than fl owing within a defi ned
channel, or percolating into the soil. See also
erosion
.
Run - on
Rainfall or other water that fl ows unchan-
nelized over the land surface from
runoff
elsewhere.
Usually run-on sites are much smaller than runoff
areas.
Secondary forest
- See
forest
.
Seed bank
The stock of viable seeds, spores and
other plant
propagules
in the soil. The longevity of a
seed bank may be between one or a few years to
several decades or more depending on the
vegetation
type
and its composition.
Seminatural ecosystem
An ecosystem, often part
of a
seminatural landscape
, that is extensively
managed with the aim to assure the conservation of
the biotic community (and the associated environ-
mental conditions) characteristic of the
cultural land-
scapes
of the early twentieth century in Europe,
before the introduction of artifi cial fertilizers.
Seminatural landscape
(synonymous with
Arcadian
landscape
) Seminatural managed or protected
natural areas, and extensively used
cultural land-
scapes
, wherein, when well-managed,
biodiversity
is
enhanced while also assuring maintenance of
pro-
duction systems
providing goods and services to
people (cf. Swart
et al
. 2001). See also
seminatural
ecosystem
.
Shrubland
A
vegetation type
(and the associated
biotic community
), that is limited in stature to roughly
(1 - )2 - 4( −8) m in height. Examples include the
mallee of southern Australia, matorral of central
natural capital
stocks to improve the
