capacities defined by limits on keyresources
(e.g.food) in closed systems. These are gen-
eralizations, in some sense crude, but they
generally point to an ecology dominated by
generalizable ideas about discrete, ontologic-
ally real ecosystems whose behaviour is pre-
dictable, and whose tendencies are towards
increasing biological diversity and stability if
left undisturbed by human action.
Yet if twentieth-century environmentalism
and ecology have shared an affinity, ecology’s
attempt to define and speak for a strictly non-
human nature has raised some difficult issues
that ecology has been, as yet, unable to resolve.
These issues are in part invoked by the transi-
tion from Clementsian and systems ecology to
the so-called ‘new ecology’ achieved by degree
over approximately the past two decades. New
ecology has numerous facets, but is generally
characterized by an embrace of complexity,
history and path dependence (seecomplexity
theory); an appreciation of interconnected
geographicalscalesin ecological relationships;
a retreat from the broad law-like generaliza-
tions of systems ecology; and, critically, an
embrace of change, not constancy, as the new
normal (Botkin, 1990). Ecosystems in this
paradigmare increasingly seen as open to the
point at which defining them robustly becomes
increasingly problematic. Moreover, disturb-
ances from volcanic eruptions, fires, storms,
pest outbreaks and the like are seen as endemic.
Empirical studies of ecological succession
following disturbance – for example, in the
aftermath of the Mount St Helens eruption
in Washington State, USA – also demonstrate
that ‘recovery’’ does not necessarily tend
towards pre-disturbance communities, nor does
the strict lineage of succession posited by
Clementsian ecology strictly apply (Swanson,
1987). Rather, ‘recovery’ depends somewhat
on initial conditions, including the legacy of
pre-disturbance communities.
For these and other reasons, the new
ecology is typically more agnostic about what
communities of organisms may be character-
ized as ‘normal’ in any given location. Many
implications follow from this, including a sig-
nificantly diminished capacity for ecology to
provide the baseline against which environ-
mental degradation is defined. And with this,
more overtly political ecologies become neces-
sary, based for instance, on the increase or
decrease inlandscapefunctions of various
kinds (e.g. fuelwood production, hydrological
recharge). At the same time, new ecology is
much less able to sharply and categorically
delineate between natural dynamics and
those influenced by anthropogenic processes
because of the acceptance that change is just
as endemic in nature as is stability (for discus-
sion, see Demeritt, 1994a; Worster, 1994).
This in turn has made ecology a much less
reliable foundation for environmental policies
that would strictly delineatenatureandcul-
ture; for example, conventionalwilderness-
oriented parks and protected areas, aimed at
biodiversityconservation(Zimmerer, 1994a).
The new ecology has also more generally
prompted considerable ontological soul
searching among ecologists. And yet, as ecol-
ogy has struggled to come to terms with com-
plexity, context, path dependence, scale and
the basis of inter-subjective knowledge claims
about the non-human world, there remain
strong parallels and linkages between ecology
and geography, not least in embrace of the
pervasiveness ofhybridsthat transgress for-
merly stable categories, be they ecosystem
boundaries or nature–society dualisms
(Zimmerer, 2000; Whatmore, 2002a). specometrics A term coined by Stephen
Raudenbush (see Raudenbush and Sampson,
1999) to assess the nature of ecological settings,
using thequantitative methodsof multi-level
(see multi-level modelling) and spatial
modelsto exploit spatial dependence in order
to improve the reliability and validity of meas-
ures of neighborhood social processes (cf.con-
textual effect; neighbourhood effect).
Unlike traditional factorial ecology (seefactor
analysis), which uses aggregate, usually
census, data to characterize places, ecometrics
uses data on individuals plus systematic social
observation as repeated measures of place
characteristics. It is also concerned with how
places change over time. kjSuggested reading
Raudenbush and Sampson (1999); Raudenbush
(2003).economic base theory A theory that
explains urban and regional growth in terms of
a division of employment into basic and non-
basic sectors. Thebasic sector(B) comprises
those industries that meet external or export
demand, and the location and growth of this
sector is viewed as a function of national
and international forces. Thenon-basic sector
(S) is locally oriented employment, servicing
the total local population (P). The total popu-
lation is a function of total employment (E)
and the economic base relationships are as
follows:Gregory / The Dictionary of Human Geography 9781405132879_4_E Final Proof page 177 1.4.2009 3:17pmECONOMIC BASE THEORY