Assessment of ecological and socioeconomic functions, synergies and trade-offs across different land-use systems

With its focus on valuation of local synergies and trade-offs among these functions, the research efforts combined in Focus 1 centre on three Hypotheses:

Transformation of rainforest to monoculture production systems is associated with a strong decline in biodiversity and ecological functions, however, these monoculture production systems are socioeco-nomically more valuable than rainforests, resulting in ecological-socioeconomic trade-offs.
Differences in management or ecological setting of rubber and oil palm plantations have both additive and interactive effects on ecological and socioeconomic functions, resulting in non-linear relationships and both synergies and trade-offs among and between functions.
Enrichment of oil palm plantations by planting of indigenous multi-purpose trees and reduced-input oil palm management mitigate the ecological-socioeconomic trade-offs that are associated with the trans-formation of tropical lowland forest to oil palm monoculture.

Focus 1 intensively worked on an interdisciplinary manuscript on socioeconomic-ecological trade-offs of land-use transitions in Jambi Province. The resulting publication (Grass et al. in press, Nat Comm) brings together researchers from clusters A, B, C and Z and provides an in-depth analysis of the non-linear relationships between land-use transitions of smallholders from forest and jungle rubber to rubber monocultures and oil palm monocultures, and trade-offs with biodiversity, ecosystem functions and profits of farmers. Land-use transitions can enhance the livelihoods of smallholder farmers but potential economic-ecological trade-offs remain poorly understood. We find widespread biodiversity-profit trade-offs resulting from land-use transitions from forest and agroforestry systems to rubber and oil palm monocultures, for 26,894 aboveground and belowground species and whole-ecosystem multidiversity (Fig. 1).

Focus 1 - Fig 1

Fig. 1. Species richness changes non-linearly with increasing profits from land-use transitions by smallholders in an Indonesian landscape.
Land-use systems were primary degraded lowland rainforest (F), agroforestry jungle rubber (J), rubber monoculture (R) and oil palm monoculture (O). (A) Species richness and profit estimates were derived from plot-level data in eight replicates per land-use system. Biodiversity-profit trade-offs were predicted using simulation-extrapolation (SIMEX) of richness-profit relationships (thin lines: SIMEX predictions; shaded areas: 95% confidence bands). Predictions for biodiversity were based on species richness of all species (black lines) and of species that were present in rainforest (red lines). (B) Mean profit per land-use system based on the crop yields in the 32 ecological study plots (left panel) and Kernel density estimates of profit distributions from 701 smallholder household interviews (right panel). Boxplots represent the median (black bars), the 25–75% intervals (box edges) and the 1.5 interquartile range (whiskers).

Despite variation between ecosystem functions profit gains come at the expense of ecosystem multifunctionality, indicating far-reaching ecosystem deterioration. We identify landscape compositions that can mitigate trade-offs under optimal land-use allocation but also show that intensive monocultures always lead to higher profits (Fig. 2). These findings suggest that, to reduce losses in biodiversity and ecosystem functioning, changes in economic incentive structures through well-designed policies are urgently needed.

Focus 1 - Fig 2

Fig. 2. Optimized landscapes for highest-possible levels of biodiversity or ecosystem functioning with increasing profits from agricultural production.
Optimized landscape compositions are shown for examples of taxonomic groups and ecosystem functions as well as for multidiversity and multifunctionality considering all studied groups and functions, respectively. Each bar represents a landscape solution as identified by a genetic algorithm, fed with plot-level information on biodiversity or ecosystem functions and profits of smallholder farmers. Colors indicate the composition of landscape solutions, i.e., the proportional share of the four studied land-use systems. Red dots indicate the realized biodiversity or ecosystem function for a given landscape composition, connected by lines to visualize trends with increasing profit expectations. Realized values are scaled between 0 and 1, whereby 1 corresponds to 100% of biodiversity (all sampled species present) or ecosystem functioning (all function indicators at their maximum) at the landscape level. A priori defined profit expectations: 0; 200; 400; 600; 800; 1000 USD ha-1 year-1

As a follow-up Focus 1 will compare the data on different oil palm systems (smallholder, estate, upland vs. riparian), oil palm management strategies (EFForTS-OPMX) and oil palm biodiversity enrichment (EFForTS-BEE) gathered by the CRC in the past two phases, to identify best management practices that mitigate economic-ecological trade-offs. In addition, Focus 1 will play a major role in synthesizing local findings on the social, economic and ecological functions of tropical rainforest transformation systems within the framework of the novel Landscape Assessment.

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