Study locations and experimental design
EFForTS works in Jambi Province which is located in the south-western part of Sumatra in Indonesia – a tropical lowland rainforest area in Southeast Asia (Fig. 1, Google maps).
Two landscapes within Jambi Province were intensively studied in Phases 1 and 2, comprising the two main remaining large swaths of lowland rainforest: National Park Bukit Duabelas (Bukit 12) and Harapan Rainforest (see Fig. 2).
Our research activities focus on three land-use systems:
(i) lowland rainforest as reference sites,
and smallholder-owned monoculture plantations of
(ii) rubber and
(iii) oil palm.
Lowland rainforest reference plots represent old-growth forest but have been subject to selective logging in the past. Contiguous areas of primary rainforest are no longer existing in Jambi, but the selected logged-over lowland rainforest reference sites have a similar forest structure (Kotowska 2015) and species composition. In each of the two landscapes (comprising blocks in a randomized complete block design), four replicates of each of the three land-use systems (including the lowland rainforest as reference) were investigated. These 24 plots constitute our Core Plot Design; investigating these core plots is mandatory for all EFForTS Scientific Projects (SPs) (Fig. 3).
In addition to investigating the three dominating land-use systems within the EFForTS Core Plot Design, future management options of oil palm plantations are investigated in two experiments:
(1) The EFForTS-BEE has been established in Phase 1 on the privately-owned oil palm plantation PT Humusindo in the Harapan landscape (see below). The experiment investigates different ways of ecological restoration and biodiversity enrichment of oil palm plantations using native multipurpose trees and aims at providing urgently needed empirical data to evaluate the effectiveness of prominently proposed designer landscapes.
(2) EFForTS-OPMX was established in Phase 2 in the Harapan landscape and investigates the effects of reduced nutrient and pesticide use on ecological and socioeconomic functions of oil palm plantations.
Additionally, a climate tower (A03) for studying the exchange of CO2, water vapour and energy between an oil palm plantation (same plantation as EFForTS-OPMX) and the atmosphere was installed in Phase 1 and has been running continuously since then.
Both experiments will form an essential component of Phase 3, as they investigate principal questions of how to establish sustainable oil palm management systems, optimizing both conservation needs and socioeconomic benefits, and restore important ecological functions in an impoverished oil-palm landscape, the overall general aim of EFForTS and Phase 3. In addition to these experiments, to cover the full range of land-use systems, the Landscape Assessment with an additional 100 plots will be established in Phase 3. Further, following the program of Phases 1 and 2, the Core Plot Design and the 100 plots of the Landscape Assessment will be closely associated to the socioeconomic surveys, which is important for a comprehensive understanding of socioeconomic causes, consequences and possible mitigation of land-use changes. Investigating these new Landscape Assessment plots through rapid assessment tools is mandatory for all natural sciences projects in Phase 3. Socioeconomic data such as inputs, outputs and profits from these plots will be collected by projects from Group C.