History, cculture aand cconservation
the number of bird and mammal species
(combined) and the number of plant
species as a measure of its biological
diversity.
This paper outlines the methods used to cre-
ate the IBCD and the main results obtained;
space does not permit discussion of many
important details. Readers wanting a full
explanation are referred to the source docu-
ment,^3 which is available through Terralingua
(www.terralingua.org).
Components of the IBCD
The IBCD has three parts:
A biocultural diversity richness component
(BCD-RICH),which is a relative measure
of a country’s “raw” biocultural diversity
using unadjusted counts of the five indi-
cators.
An areal component (BCD-AREA),which
adjusts the indicators for land area and
therefore measures a country’s biocultural
diversity relative to its physical extent.
This is important to measure because
large countries are more likely to have
higher biological diversity than small
countries. Nevertheless, some small coun-
tries have biological diversity that is high
relative to their area, just as some large
countries have low biological diversity rel-
ative to their area. BCD-POP adjusts the
rankings to account for these situations.
A population component (BCD-POP),
which adjusts the indicators for human
population and therefore measures a
country’s biocultural diversity relative to
its population size. This is important to
measure because countries
with high human populations
are more likely to have high-
er cultural diversity than
countries with small popula-
tions. Nevertheless, some
countries with small popula-
tions have cultural diversity
that is high relative to their population
size; and, conversely, some countries with
high populations have cultural diversity
that is low relative to their population
size. BCD-POP adjusts the rankings to
account for these situations.
BCD-RICH is the most straightforward meas-
ure of biocultural diversity, but BCD-AREA
and BCD-POP are equally important compo-
nents of the IBCD because they highlight
countries that are small in area and/or popu-
lation size but which have relatively high bio-
cultural diversity. In effect, they broaden the
analysis beyond mere counts of cultural
groups and species. As we shall see, there
are only a handful of countries that rank
highly in all three components.
Methods
Each of the three parts of the IBCD gives
equal weight to cultural and biological diver-
sity. For example, a country’s overall BCD-
RICH score is calculated as the average of
its cultural diversity richness score (aggre-
gated from the scores for languages, reli-
gions, and ethnic groups) and its biological
diversity richness score (aggregated from
the scores for bird/mammal species and
plant species). The same holds true for BCD-
AREA and BCD-POP.
When values for these indicators are ranked
on a global basis, it becomes apparent that
biocultural diversity is not evenly distributed.
A few countries are megadiverse, with very
large values; then the ranking rapidly dimin-
ishes to much lower values found in more
typical countries. Because this makes com-
parisons among countries difficult, we used
a common log scale to produce a linear dis-
tribution.
For example, the language indicator index
for BCD-RICH is calculated as the log of the
number of languages spoken in a country
divided by the log of the number of lan-
guages spoken worldwide (Table 1). The
process was repeated for the other four indi-
cators to derive BCD-RICH.
there aare oonly aa
handful oof ccoun-
tries tthat rrank
highly iin aall tthree
components oof bbio-
cultural ddiversity.
