Cultural Geographers of a more theoretical
bent. In the past decade, however, some cul-
tural geographers who feel that New Cultural
Geography had been too discursive and
human in its focus, paying insufficient atten-
tion tonature, have come to a new appreci-
ation of some of the more environmentally
focused contributions of the Berkeley School
(Price and Lewis, 1993). jsd
Suggested reading
Leighly (1963); Wagner and Mikesell (1962).
bid-rent curve A plot of the rent that
people are prepared to pay against distance
from some point, usually the city centre.
Rent bids generally decrease with increasing
distance from a city or its centre where land
values are highest, so a bid-rent curve slopes
down in a diagram with rent on the vertical
axis and distance displayed horizontally (see
alonso model;distance decay). The curve is
sometimes shown as convex to the graph’s
origin, to reflect sharp decreases in rent with
short distances from the city (centre), levelling
off with increasing distance. Bid-rent curves
are an important element in models of both
urban and agricultural land use (cf.von thu
..nen model). dms
biodiversity A term defined in the United
Nations Convention on Biological Diversity
(CBD) as ‘the variability among living organ-
isms from all sources includinginter aliater-
restrial, marine and other aquaticecosystems
and the ecological complexes of which
they are part; this includes diversity within
species, between species and of ecosystems’
(Article 2). The stated objectives of the
Convention are ‘the conservation of biological
diversity, the sustainable use of its compon-
ents and the fair and equitable sharing of the
benefits arising out of the utilization of genetic
resources’ (Article 1).
As Jeffries (1997) points out in his account
of the rise of biodiversity as a matter of scien-
tific and policy concern, the term was barely
used in scientific or policy communities before
the 1980s. He tracks its rise to the develop-
ment of a scientific infrastructure associated
with the new field of conservation biology,
including a learned society (the Society for
Conservation Biology), a scientific journal
(Conservation Biology) and an undergraduate
teaching programme (at the University of
California, Berkeley), all established in 1985.
This body of work focused on recording and
accounting for the observed and hypothesized
decline in the variety of living organisms in any
number of contexts – a decline represented as
a human-driven process of extinction. Defined
by its sense of urgency, biodiversityconserva-
tionreadily took on the mantle of a global
environmental crisis in both scientific and
popular imaginations through such totemic
(and telegenic) spaces as the Amazonian rain-
forest. The rapid uptake of this new scientific
agenda in the world of international environ-
mental policy-making, centred on the United
Nations, is attributed by Takacs (1996) to the
influential efforts of some of its leading scien-
tific sponsors – whom he collectively labels the
‘rainforest mafia’, notably the eminent US
biologist E.O. Wilson.
Efforts to reduce the rate of decline in bio-
logical diversity associated with global and
local management practices fostered under
the CBD, such as Biodiversity Action Plans,
are bound up with the rather different agendas
of those concerned with exploiting biodiversity
as a new form of naturalresource(Bowker,
2000; see alsogenetic geographies). Among a
number of problematic tensions inherent in
these management regimes, two have drawn
significant and persistent political fire. First,
the CBD regime sets biological diversity apart
from, and at odds with, human society and
activity. This is contradicted by the historical
record of co-evolution between humans,
plants andanimals, which has left its mark,
through processes such asdomestication,on
the genetic and phenotypic diversity of our
biological heritage today. Second, the CBD
regime has generated some highly contested
management arrangements, such as those
permitting the slaughter of animals belonging
to mammal species threatened with extinction
in order to generate income to invest in
the protection of the remaining species
population. swSuggested reading
Bowker (2000); Jeffries (1997); Takacs (1996);
United Nations Environment Programme (1992).biogeography One of the oldest sub-fields
of the discipline, concerned with describing
and explaining the spatial patterns of the dis-
tribution of living organisms: where they are,
where they are not and why. While this field of
concern has now become tightly bound up
with the rise of scientific and policy effort to
manage species extinctions and conserve bio-
logical diversity (seebiodiversity), the study
of biogeography represents an important and
generative common ground between humanGregory / The Dictionary of Human Geography 9781405132879_4_B Final Proof page 46 31.3.2009 11:01amBID-RENT CURVE