Any particular area in a landscape provides multiple ecosystem services. As we attempt to extract more ecosystem services out of a landscape – for example, the storage of carbon, crop production for food and biofuels, and the conservation of biodiversity – conflicts often arise regarding choice of dominant land use. Evaluation of synergies and trade-offs among potentially competing or complementary land uses ultimately depends on the value given to ecosystem services by the people inhabiting the landscape, or by those extracting ecosystem services from afar. To help societies make such difficult choices, a quantitative, spatially explicit determination of the ecosystem services provided by a landscape is valuable. Understanding and quantifying the relationships among and trade-offs between different ecosystem services has therefore become a very active area of research (e.g., Naidoo and Ricketts 2006; Bennett et al. 2009).
This study explores the synergies and/or trade-offs among five ecosystem services (i) carbon flows and storage; (ii) food provision; (iii) biodiversity richness; (iv) water quality and storage; and (v) recreation in the Australian Capital Region (ACR), a 300 x 300 km region in southeastern Australia centered on the capital, Canberra. Three approaches are proposed: i) a spatially-explicit qualitative and quantitative analysis of the region based on land use/cover, ii) a multi-criteria analysis based on the opinions of relevant experts; and iii) combination of both land-use/cover maps and survey outcomes to create a map of possible trade-offs in ecosystem services for the ACR
Results/Conclusions
An initial example of a trade-off analysis estimates the change in the carbon cycle resulting from an increase in food production. A ‘crop index’, based on the suitability of soil, climate and terrain to support a wheat crop (the most common crop in the ACR) was used as an indicator of the potential for each land-cover class to be converted into cropland. In addition, the Net Primary Productivity (NPP) was calculated for each pixel that was converted to cropland from another land-cover class. The result was a net loss of 11.45 Mt of NPP per year after the change in land use, compared to a gain of around 7 Mt per year of wheat.
Preliminary results of the multi-criteria analysis considering expert opinions have shown that the top three ecosystem services are i) water quality and storage, ii) biodiversity and iii) carbon uptake and storage. These ecosystem services are mainly provided by forests and woodlands.