In Sumatra, Indonesia, what were previously lowland rainforest landscapes have been transformed into a mosaic landscape with patches of rainforest interspersed with rubber and palm oil plantations. In this context, the project’s guiding question is as follows:
What kind of landscape mosaic optimises the ensemble of biodiversity, ecosystem functions, and economic benefit based on the synergies and trade-offs that we have to account for?
We plan to develop an integrated model of different aspects of ecological diversity, ecological functions, and socio-economic functions. We will use a MAS/LUCC modelling approach (multi-agent system models of land-use and land-cover change) because of its high suitability for the integrated modelling of ecological-economic systems. The model will be used to (1) integrate diversity, and functions and (2) scale up from the local level to the landscape level and broader scales.
Contribution to International Research
We expect the project’s main result to be an integrated strategic model that links the ecological and economic processes of the transformation system to the landscape. We anticipate that we will identify the trade-offs and synergies within and between ecological and socio-economic functions, and how these trade-offs and synergies change across transformation systems, spatial configurations and scales. The project will thus contribute to the interdisciplinary research on rainforest transformation systems, which are playing an increasing role across the tropics. It will also illuminate the complex interplay between the environment and human action in a rapidly developing region that is characterized by global cash-crop cultivation.
Research Design and Methods
The purpose of our model is to provide an integrated, exploratory tool for the analysis of spatio-temporal land-use scenarios with respect to the four transition systems. We will develop a coupled multi-agent system model of land-use and land-cover change – that is, a MAS/LUCC model. More specifically, we will adopt an agent-based approach (MAS) to model the behaviour and land-use decisions of individual households within the landscape. Households interact with the landscape with the aim of maximizing their economic returns, but they also affect ecological functions such as the diversity of plants and animals, community stability, pollination, primary production, decomposition, and carbon sequestration.
A spatial grid of cells will represent the landscape and its land-use patterns (LUCC). Each grid cell will be characterised by its land-use type and will be the basic entity for modelling a range of ecological and economic functions in space and time. Possible land-use types include tropical lowland forest, jungle rubber, rubber plantation, palm oil plantation, and "other". With this approach, very different landscapes that differ in composition (proportion of land covered by the different transformation systems) and spatial configuration can be modelled. The combined agent-based and grid-based approach provides the flexibility needed to model diverse ecological and socio-economic functions. Households and landscape will be linked by assigning land to households based on their current land use. Interactions between grid cells – for example, animal movement on the ecological side and intrahousehold dynamics on the economic side – will be explicitly included. With the goal of reaching an integrated understanding of the interaction between the ecological and economic functions of landscapes, we will conduct computer experiments using realistic and artificial landscapes and households.
We have developed an integrated ecological and socioeconomic land-use change model for Jambi, Sumatra, and Indonesia. A description of the model and first analyses have been published in PLoS ONE. The model can be used an exploratory tool to analyse how tropical land-use change affects ecological and socio-economic functions. The model analysis seeks to determine what kind of landscape mosaic can improve the ensemble of ecosystem functioning, biodiversity, and economic benefit based on the synergies and trade-offs that we have to account for. More specifically, (1) how do specific ecosystem functions, such as carbon storage, and economic functions, such as household consumption, relate to each other? (2) How do external factors, such as the output prices of crops, affect these relationships? (3) How do these relationships change when production inefficiency differs between smallholder farmers and learning is incorporated? The overall results reveal complex interactions between the economic and ecological spheres. For instance, model scenarios with heterogeneous crop-specific household productivity reveal a comparatively high inertia of land-use change. Our model analysis even shows such an increased temporal stability in landscape composition and carbon stocks of the agricultural area under dynamic price trends. These findings underline the utility of ecological-economic models to act as exploratory tools which can advance our understanding of the mechanisms underlying the trade-offs and synergies of ecological and economic functions in tropical landscapes.