In Sumatra, Indonesia, previous lowland rainforest landscapes have been transformed into a predominantly agricultural, smallholder-dominated landscape mosaic. The relationships between the spatial composition and configuration of the landscape, different aspects of biodiversity, ecosystem functioning, and economic benefit are expected to be interdependent and often non-linear. Land-use change decisions are often a choice between socio-economic benefits or biodiversity benefits, with the other function suffering.
In order to minimize these trade-offs, our project aims to understand and explore ways in which to support biodiversity and ecosystem functioning while serving human needs. We have developed and will further refine EFForTS-ABM, an integrated ecological-economic land-use change model. EFForTS-ABM is spatially-explicit and follows a combined agent-based and grid-based approach. Household agents own agricultural fields within a forested landscape and take farming and thus land-use decisions that affect diverse ecological and socio-economic functions. EFForTS-ABM is equipped with EFForTS-LGraf, a landscape generator that not only generates input maps for our model, but also serves as a stand-alone tool for specific landscape-scale analyses. Model structure and parameterization are based on field data from multiple EFForTS projects.
While the representation of economic decision-making by farmers in EFForTS-ABM is well elaborated analytically and empirically founded, and has been used for several model analyses, we are currently in the process – and will continue in the beginning of Phase 3 – of adding more ecological detail on the spatiotemporal distribution of (a) biodiversity of birds, plants, insects, and soil microbial communities, and of (b) carbon, in response to land-use changes and agricultural management. Furthermore, we will continuously refine model algorithms and update model parameterizations based on new data from project groups within EFForTS. We will also evaluate policy scenarios by implementation of heterogeneous management options into EFForTS-ABM. With these additional details, EFForTS-ABM will be an even more useful tool for exploring the complex interactions and trade-offs between economic smallholder household decisions and ecological functions. This will be done, for example, by investigating landscape mosaics where economic benefit is high as starting points to search for alternative mosaics that increase ecosystem services and biodiversity markedly, while having minimal impact on the economic benefits. The model will thus be used to advance the understanding of the mechanisms underlying the trade-offs and synergies of ecological and economic functions in tropical landscapes, through 1) identifying and highlighting the major trade-offs and synergies between ecological and economic functions, and 2) scaling up from micro and local to landscape and broader scales, including an assessment of long-term drivers and consequences of land-use change. Our guiding question is what kind of landscape mosaic optimizes the ensemble of biodiversity, ecosystem functioning, and socio-economic benefit. The project plays a central role in integrating the research outcomes of EFForTS.