#marxan

Like many other papers I've read, this paper begins by addressing the number one shortfall in successful conservation planning based on the value of ecosystem services, the poor characterization and understanding of the flow of services. Plans to conserve biodiversity are generally straight forward, with "features" (i.e. the species) and "targets" (i.e. the goals of conservation). However, the protection of both biodiversity and services together becomes far more complex.

The authors focus on 6 services and the services' impact in the Central Coast ecoregion of California. The services were as follows, carbon storage, crop pollination, flood control, forage production, outdoor recreation, and water provision. The authors decision was based on ample data for these services in this region. The authors then address three key questions,

(i) How much of each service is being generated by each land parcel?

(ii) What are the spatial associations between the lands required for protecting biodiversity and supplying different ecosystem services?

(iii) How much of each ecosystem service—plus biodiversity protection—is provided by a network of lands prioritized for biodiversity, compared to networks designed for multiple services?

The authors found that many of the services had distinct spatial distributions. Furthermore, there was little spatial correlation across the services.

Figure 2 from Chan et al.

The authors are able to highlight that conservation strategies that do not account for biodiversity, or only minimally count for it, pose a potential risk, since at least in this region this strategy will lead to little protection for biodiversity. Inversely, they found that if biodiversity was the central target for conservation, most services targets were met, with only small additional areas needed to fill the gap.

The paper uses MARXAN to prioritize conservation networks based on the 6 services and biodiversity. The authors found that the tool still lacks some key features for this use. Each service has its own planning requirements (i.e. protecting pollinators is different than creating recreation), and so each layer should be able to have its own suitability layer. Next, MARXAN does not handle any measurements for potential for loss. It is more useful is conservation can target areas of the network based on their associated short and long-term risk. See text for full list of suggested improvements.

The paper is significant in its careful weighting and comparison of trade-offs across different conservation plans. As stated by the authors, using this type of approach in conservation planning could create a significant shift in way of thought as well as the geographic areas being protected.