Continuation of research and new directions in Phase 3

Phase 3 will greatly benefit from the establishment of these experiments in Phases 1 and 2 because we can now investigate ecological and socioeconomic trade-offs in well established experimental settings. The focus of Phase 3 From heterogeneity towards sustainable landscapes builds on these ecological and socioeconomic assessments integrating Phases 1 and 2. Further, we aim at providing policies towards the development of more sustainable management of tropical lowland rainforest regions. EFForTS is well positioned for achieving this goal by extending Project Group C with three new projects in Phase 3. The new project C12 Paul will derive robust recommendations on desirable farm designs to mitigate trade-offs between socio-economic and ecological functions under heterogenous site and household conditions. Also, the recently started project C10 Kis-Katos has a strong focus on integration by investigating policies to mitigate ecological and socioeconomic conflicts at large scale. Further, C11 Lay et al. focuses on the integrated analysis of policies for sustainable development of rural regions.

The Landscape Assessment builds heavily on results of Phases 1 and 2 and aims at integrating these results at the landscape level, which was the explicit major goal of EFForTS from the beginning. For extrapolating to the lowland rainforest region of Jambi province (excluding peatlands), we miss some important land-use systems such as fallow land and shrublands and we did not yet investigate the full variability of the main land-use systems, i.e. of rainforest, and rubber and oil palm plantations. This is because the Core Plot Design aimed at typical conditions and minimize variability in potentially confounding factors (e.g. plantation age). In Phase 2 we expanded the Core Plot Design by including hotspots of heterogeneity such as riparian sites but did not investigate the full range of heterogeneity of land-use systems in space and time. The socioeconomic projects of EFForTS already extended their investigations to the full range of heterogeneity of socioeconomic systems in Phase 2 by including non-farm rural households and rural-urban linkages. The addition of 100 new plots and the associated rapid assessment of major environmental and biodiversity indicators will allow estimating the full range of biodiversity and ecological functions in space and time. With this, EFForTS is in the unique position to link in a comprehensive way both ecological and socioeconomic functions at the landscape level, thereby providing the foundation for integrated science-based policies and land-use decisions. Notably, the socioeconomic studies continue to include the social backgrounds of people (e.g., ethnicity, migration status, different income sources), local policies and institutions (e.g., land rights) and other related factors as important components for land-use decisions. The ecological studies in the Landscape Assessment explicitly address each of the land-use types forming part of current transformations of land-use systems including plantations to be replanted in near future as well as abandoned land (fallow/shrubland). Further, major management options of oil palm plantations, i.e. reduced input by fertilizers and weed management as well as by enrichment planting are addressed in EFForTS-OPMX and EFForTS-BEE. Notably, we will continue to collect data following our Core Plot Design in both ecological plots and socioeconomic surveys (see below; Figs 7, 8), which provides the perspective for long-term analysis of changes in biodiversity as well as ecological and socioeconomic functions in time.

As already started in Phases 1 and 2, we will continue and intensify the investigation of management options of oil palm plantations. EFForTS-BEE (B11 Hölscher/Kreft/Wollni) was established in Phase 1 with different tree species planted into an existing oil palm plantation. Planted trees are now well established and partly overtop the oil palms. Thus, EFForTS-OPMX (Z01 Scheu) established in Phase 2 is now well established with the management practices in place for three years by 2020, which enables us to investigate ecological and socioeconomic long-term consequences of reduced fertilizer input and weed management intensity in a comprehensive way.

Data from different projects of EFForTS all contribute to the integrated analysis of ecological and socioeconomic trade-offs and synergies. Such integration will be especially fostered by the three closely collaborating interdisciplinary project. The agent-based model B10 Wiegand/Lay (Dislich et al. 2018, Salecker et al. 2019) was established in Phase 1 and investigates the mechanisms underlying ecological-economic trade-offs and synergies. A07 Knohl/Veldkamp, was established in Phase 2 and focusses on the impact of land-use scenarios on the biogeochemical cycles of carbon, nitrogen and water This will be complemented by the new project C11 Lay et al., which includes researchers from all three Project Groups (A, B and C), will model socioeconomic and ecological functions of different land-use scenarios at the rural economy level and simulate the effects of possible policy interventions to reduce trade-offs and increase sustainability. Combining the different parts of the analysis will help us to develop broader concepts of socio-ecological transformation processes. This degree of interdisciplinary integration is unique.