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T.J .B. Boyle
important than the choice and design of reserves, and the enlightenment
of forestry practices outside the reserves .
In addition to the World Commission on Development and the Environment proposal that the extent of protected areas throughout the world
should be trebled, similar targets have been proposed by IUCN, UNEP
and WWF (World Conservation Union et al. , 1991), and the Caracas
declaration of the Fourth World Congress on National Parks and Protected
Areas. Whatever may constitute an appropriate target , there is no question
that , in order to protect the welfare of present and future generations at a
time of increasing human pressure on natural resources, additional areas
of land need to be protected. It is only sensible to try to ensure that the
areas protected are those which will provide the greatest future value
per unit area . The challenge lies in developing suitable procedures for
identifying such areas .
In the absence of reliable information on future value of natural resources, the logical approach is to protect areas of high diversity and
areas that contain particularly rare , or unique , resources. Such an approach has often been used, for example by Hopper and Burgman (1983),
Moran and Hopper (1983), and Sampson, Hopper, and James (1988)
for various species of eucalypts. These authors used morphological and
allozyme data from discrete populations of eucalypt species to quantify
the distinctness of the sampled populations already within protected areas .
Although such an approach is useful for species of known or potential
commercial value, it is practicable only for a small fraction of all species.
In any case, the conclusion reached for different species would soon
result in conflicting recommendations and an unrealistically large area
being proposed for protection.
An alternative approach is provided by " gap analysis" (Scott, Csuti,
Smith et al. , 1991), which is greatly facilitated by modern Geographic
Information Systems (GIS) technology. Areas of high conservation value
(e.g., old-growth forest) for different ecoregions can be compared with
existing protected areas and with areas under conflictingland use demands .
Relative diversity information (if available) can also be used to make
recommendations for areas that do not meet all criteria. For example, an
area of pristine forest in a high diversity ecoregion might be recommended
for protection even if the potential mineral value was quite high, whereas
a similar area in a low diversity ecoregion would only be recommended if
the mineral value were much lower or nil.
Other aspects that must be considred in the identification of protected
areas are the size, shape , and distribution of the areas and linkages
(corridors) among them . These issues have received much attention (e.g.,
Shafer , 1990), particularly in relation to island biogeography theory
and species-area relationships. Intuitively , large reserves will conserve
biodiversity more efficiently than small reserves , and it is better to minimize the length of boundary per unit area (leading to more circular,
T.J .B. Boyle
important than the choice and design of reserves, and the enlightenment
of forestry practices outside the reserves .
In addition to the World Commission on Development and the Environment proposal that the extent of protected areas throughout the world
should be trebled, similar targets have been proposed by IUCN, UNEP
and WWF (World Conservation Union et al. , 1991), and the Caracas
declaration of the Fourth World Congress on National Parks and Protected
Areas. Whatever may constitute an appropriate target , there is no question
that , in order to protect the welfare of present and future generations at a
time of increasing human pressure on natural resources, additional areas
of land need to be protected. It is only sensible to try to ensure that the
areas protected are those which will provide the greatest future value
per unit area . The challenge lies in developing suitable procedures for
identifying such areas .
In the absence of reliable information on future value of natural resources, the logical approach is to protect areas of high diversity and
areas that contain particularly rare , or unique , resources. Such an approach has often been used, for example by Hopper and Burgman (1983),
Moran and Hopper (1983), and Sampson, Hopper, and James (1988)
for various species of eucalypts. These authors used morphological and
allozyme data from discrete populations of eucalypt species to quantify
the distinctness of the sampled populations already within protected areas .
Although such an approach is useful for species of known or potential
commercial value, it is practicable only for a small fraction of all species.
In any case, the conclusion reached for different species would soon
result in conflicting recommendations and an unrealistically large area
being proposed for protection.
An alternative approach is provided by " gap analysis" (Scott, Csuti,
Smith et al. , 1991), which is greatly facilitated by modern Geographic
Information Systems (GIS) technology. Areas of high conservation value
(e.g., old-growth forest) for different ecoregions can be compared with
existing protected areas and with areas under conflictingland use demands .
Relative diversity information (if available) can also be used to make
recommendations for areas that do not meet all criteria. For example, an
area of pristine forest in a high diversity ecoregion might be recommended
for protection even if the potential mineral value was quite high, whereas
a similar area in a low diversity ecoregion would only be recommended if
the mineral value were much lower or nil.
Other aspects that must be considred in the identification of protected
areas are the size, shape , and distribution of the areas and linkages
(corridors) among them . These issues have received much attention (e.g.,
Shafer , 1990), particularly in relation to island biogeography theory
and species-area relationships. Intuitively , large reserves will conserve
biodiversity more efficiently than small reserves , and it is better to minimize the length of boundary per unit area (leading to more circular,