Systematic conservation planning and efficient biodiversity offsets for a green economy

Biodiversity offsets are conservation outcomes that are designed to compensate for, or offset, biodiversity losses from development or other non-conservation land/water uses. A core goal is “no net loss of biodiversity”. This material is part of a submission to the Business and Biodiversity Offsets Program (BBOP) consultation process.

Biodiversity offsets are conservation outcomes that are designed to compensate for, or offset, biodiversity losses from development or other non-conservation land/water uses. A core goal is “no net loss of biodiversity”. While biodiversity offsets typically are considered in the context of individual development projects, such offsets also may be designed to compensate for biodiversity losses arising from multiple development sites, at a broader regional scale. Regional-scale design of biodiversity offsets was linked early on to systematic conservation planning (Faith et al 2001; Faith and Walker, 2002). This link to systematic conservation planning (SCP) methods was based on the principle of “complementarity”. Here, the marginal biodiversity gain or loss for a given area is context dependent; it depends on the representation and persistence of elements of biodiversity in other areas. In practice, biodiversity surrogates are used, so that complementarity values reflect changes in representation and persistence for overall, wholesale biodiversity. Such complementarity values, as part of SCP, were extended beyond the conventional reserve-selection applications to provide a “regional biodiversity economics”, supporting offsets, levies, subsidies, and incentives (Faith et al 2001; Faith and Walker, 2002).

The Business and Biodiversity Offsets Program (BBOP), which provides a global, multi-stakeholder, forum to help develop standards for biodiversity offsets, has called for applications of systematic conservation planning for design of offsets:
“Systematic conservation planning approaches can make a significant contribution to effective offset design by simultaneously integrating information on the spatial variability in both biodiversity benefits and implementation costs among different offset candidates” (BBOP draft). BBOP were unable to cite any existing applications of complementarity to biodiversity offsets. Faith et al (2001) did present maps for Papua New Guinea illustrating calculation of complementarity values for offsets, but this kind of approach has not been applied. (note 1)

Note that standard SCP methods for balancing development and conservation can be interpreted as operating as if the approach is seeking efficient biodiversity offsets. SCP allocates development to some places, but it captures those lost elements of biodiversity through allocated conservation to other (often cheaper) places. This is the basis for the efficiency of land-use allocations provided by the approach. Such efficiency is not yet part of regional biodiversity offsets programs. Here, I comment further on that SCP biodiversity offsets framework, particularly focussing on the idea that compensatory payments for conservation are linked to complementarity values of the compensating places (Faith et al 2001).

Assume that a given region has some existing set of protected areas. A nominated development area then has some complementarity value to that protected areas set. One basic offsets strategy then compensates for the loss of that (potential) contribution by finding one or more alternative areas that provide, if protected/conserved, at least that complementarity gain. By using SCP, these areas have minimum cost, with the payment reflecting degree of complementarity requiring offsetting.

An alternative strategy requires that the compensating areas , if protected/conserved, make the development area’s complementarity to the new protected-areas set go to 0 (if the nominated development area now were protected, it would provide no measurable biodiversity gain). Again, by using SCP, these areas have minimum cost, with the payment reflecting degree of complementarity requiring offsetting.

Using this approach, a candidate development site can be flagged if it has irreplaceable elements such that no offset areas can reduce its complementarity value to 0. That is, the offset process in that case cannot produce “no net loss”.

A candidate development site might be flagged as problematic for another reason relating to the no net loss criterion. Note that, even when the complementarity value of a development site is totally compensated by protection of other sites, this may not be enough to guarantee the desired no net loss of biodiversity for the overall offsets program. The reason is that the offsetting for one or more sites may constrain the prospects for later successful offsets. Specifically, early offsets choices could mean that the region is no longer able to achieve its overall biodiversity conservation goal for some given total costs constraint. The no net loss criterion therefore is not satisfied. An example of this kind is found in Faith and Walker (2002; Fig5b*). This problem relating to the need to “plan ahead” provides a major source of uncertainty for regional offsets programs.


Faith, D. P., Walker, P. A. and Margules, C. R., (2001). Some future prospects for systematic biodiversity planning in Papua New Guinea – and for biodiversity planning in general. Pacific Conservation Biology 6:325-343.

Faith, D. P. and Walker, P. A. (2002)The role of trade-offs in biodiversity conservation planning: linking local management, regional planning and global conservation efforts. J. Biosci. 27 (Suppl. 2) 393–407.

*In that SCP example, 4 sites provide development, and other protected sites offset losses through SCP, so that the regional biodiversity target is approximately achieved. Note that in fig 5b, the development gains for 3 of the sites are not recorded; if they were, the upper frontier curve would shift to the left, reflecting 81 units of reduced total cost. Nevertheless, if the region were constrained to the original cost of about 400 units, the region now would not be able to achieve its biodiversity conservation goal, implying a net loss of biodiversity.

 (note 1)

BBOP guidelines documents now highlight applications of systematic conservation planning to biodiversity offsets:

“Currencies based only on site level information are useful when there is a poor understanding or lack of data on wider patterns of biodiversity. ….. By contrast, context-dependent currencies are able to assess the contribution of local biodiversity losses and gains to changes in conservation priorities at a regional scale … Both complementarity and persistence-based currencies have been used in conservation planning (see Pressey et al. 2007; Walker et al. 2008; Moilanen et al. 2009) as well as to regional biodiversity offset site selection problems (Faith et al., 2011; Faith and Walker, 2002).”

see  Business and Biodiversity Offsets Programme (BBOP). 2012. Resource Paper: No Net Loss and Loss-Gain Calculations in Biodiversity Offsets. BBOP, Washington, D.C.
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“There are many different tools and approaches for landscape-level planning and analysis. The majority of tools and approaches are GIS-based and make use of widely recognised systematic planning approaches (e.g., systematic conservation planning14 ) or other criteria. Some of these approaches are described in the BBOP Offset Design Handbook available at . Note that systematic conservation planning provides an excellent basis to plan for biodiversity offsets at a regional level15
15See, for example, Faith et al., 2001. Pacific Conservation Biology 6:325-343; Faith, D.P. and Walker, P.A. 2002. Journal of Bioscience 27 (Suppl. 2) 393–407.”

see   Business and Biodiversity Offsets Programme (BBOP). 2012. Guidance Notes to the Standard on Biodiversity Offsets. BBOP, Washington, D.C.
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Dr Dan Faith , Senior Principal Research Scientist email:danfaith8[at]
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