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Practical Application of Biodiversity Surrogates and Percentage Targets for Conservation in Papua New Guinea
Figure legends
Figure 1.
Trade-offs curves, adapted from Faith (1997b), illustrating 10%-based biodiversity targets. Any land-use allocation defines a point in this space. Desirable allocations are those towards the lower left. The hollow circle represents the selection of a set of areas with maximum total biodiversity, with the constraint that it total 10% of the total area, but without regard to costs or other constraints. The triangle depicts one maximally biodiverse set of areas that would have been selected if costs but no other constraints, including total area, were taken into account. It lies along a trade-offs curve of best-possible sets, the choice depending on the relative weighting of costs and biodiversity. The triangle is that solution along the curve yielding the same total biodiversity as the hollow-circle solution. The square is the best possible set achieving the same level of biodiversity protection but with various constraints, including an existing reserve system. It lies on the darker trade-offs
curve which represents the best-possible trade-offs under those constraints. The position of this curve, to the upper right of the lighter curve, implies that net benefits (regional sustainability) cannot be a great as in the absence of these constraints. The dark circle shows a hypothetical solution achieving the same biodiversity protection level, but not taking costs into account.
Figure 2.
Areas in green show the overlap of RMUs with the existing protected areas for PNG.
Figure 3.
The 4,470 Resource Mapping Units (RMUs) used as allocation units for the biodiversity priority areas.
Figure 4.
A map of PNG showing (in green) areas (RMUs) selected to form a baseline set that maximizes biodiversity representation/persistence using 10% of the total country area.
Figure 5.
Areas in red are those that must be in any set that achieves the representation/persistence target defined by the 10%-based target guideline. Areas in black are those that must be in any set that achieves the representation/persistence target defined by the 15%-based target guideline.
Figure 6.
Two conventional approaches to 10% targets applied to PNG.
a) A set of areas (in black) totaling 10% of total area, selected using existing protected areas plus an ad hoc set of areas with low value for timber production.
b) A set of areas (in green) selected based on a representation target of 10% of each vegetation type.
Figure 7.
A figure re-drawn from Faith (1995b), illustrating the effect of probabilities of persistence on number of protected areas needed to reach a nominated regional persistence level. The curve connecting solid circles is based on persistence values where no-protection implies 0.01 probability of persistence of forest type in a given area, while protection implies a 0.50 probability of persistence. The number of protected areas required (y-axis) is defined as the minimum number to achieve an overall regional probability of persistence of 0.95. The x axis is the number of areas in the region of a given type. For comparison, the curve connecting hollow squares is for a simple rule that requires protection of 15% of a given type (value along y-axis is simply 15% of total number of equal-sized areas).
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