Ecosystem Services and Biodiversity in a Rapidly Transforming Landscape in Northern Borneo

October Ecosystem Services and Biodiversity in a Rapidly Transforming Landscape in Northern Borneo Nicolas Labrière 0 1 2 Yves Laumonier 0 1 2 Bruno Locatelli 0 1 2 Ghislain Vieilledent 0 1 2 Marion Comptour 0 1 2 0 1 UPR Biens et services des écosystèmes forestiers tropicaux (BSEF), Centre de coopération internationale en recherche agronomique pour le développement (CIRAD), Montpellier, France , 2 Ecole doctorale ABIES, AgroParisTech, Paris , France , 3 CGIAR Research Program - Forests, Trees and Agroforestry, Center for International Forestry Research (CIFOR) , Bogor , Indonesia , 4 CGIAR Research Program - Forests, Trees and Agroforestry, Center for International Forestry Research (CIFOR) , Lima , Peru , 5 Centre d'Ecologie Fonctionnelle et Evolutive (CEFE) , CNRS , Université Montpellier II , Montpellier , France 1 Funding: This research received financial support from CoLUPSIA (EU Financed Project - DCI), AusAid (Agreement 63650 with Center for International Forestry Research), CIRAD, CRP-FTA (CGIAR Research Program on Forests , Trees, and Agroforestry) and ABIES (Ecole Doctorale Agriculture, Alimentation , Biologie, Environnements et Santé) 2 Editor: Edward Webb, National University of Singapore , SINGAPORE Because industrial agriculture keeps expanding in Southeast Asia at the expense of natural forests and traditional swidden systems, comparing biodiversity and ecosystem services in the traditional forest-swidden agriculture system vs. monocultures is needed to guide decision making on land-use planning. Focusing on tree diversity, soil erosion control, and climate change mitigation through carbon storage, we surveyed vegetation and monitored soil loss in various land-use areas in a northern Bornean agricultural landscape shaped by swidden agriculture, rubber tapping, and logging, where various levels and types of disturbance have created a fine mosaic of vegetation from food crop fields to natural forest. Tree species diversity and ecosystem service production were highest in natural forests. Logged-over forests produced services similar to those of natural forests. Land uses related to the swidden agriculture system largely outperformed oil palm or rubber monocultures in terms of tree species diversity and service production. Natural and logged-over forests should be maintained or managed as integral parts of the swidden system, and landscape multifunctionality should be sustained. Because natural forests host a unique diversity of trees and produce high levels of ecosystem services, targeting carbon stock protection, e.g. through financial mechanisms such as Reducing Emissions from Deforestation and Forest Degradation (REDD+), will synergistically provide benefits for biodiversity and a wide range of other services. However, the way such mechanisms could benefit communities must be carefully evaluated to counter the high opportunity cost of conversion to monocultures that might generate greater income, but would be detrimental to the production of multiple ecosystem services. - Competing Interests: The authors have declared that no competing interests exist. Drastic land-use transformations have occurred in the tropical forest landscapes of Southeast Asia in the past decades, leading to the disappearance of natural forests and the replacement of traditional land-use systems with monoculture plantations. On the island of Borneo, the lowland rainforests are at the crossroads of multiple and divergent interests. While these rainforests are hotspots of biological diversity with a high rate of endemism and hold important carbon stocks, they are also a major source of valuable timber, and are situated on lands that are very suitable for conversion to oil palm or other large industrial plantations [1–3]. Since the late 1960s, logging has affected most of the lowland forests [4]. Following the boom era that lasted roughly until the 2000s, large areas of logged-over forest were left unmanaged. Although several studies demonstrated the important role that these forests play in supporting biodiversity and maintaining multiple ecosystem services [5–8], they were slowly depleted through illegal logging and finally converted to oil palm plantations [9]. The detrimental effect of such large-scale land clearing on biodiversity and other services is an accepted premise [10– 13]. At the same time, as the extent of industrial agricultural areas keeps increasing, the role of traditional agricultural systems (swidden i.e., slash-and-burn and rotational fallow farming, and smallholder agroforestry systems) vs. alternative agricultural systems in providing goods and services has received much attention [14–17]. To date, however, there has been little consensus about their role in supporting biodiversity and producing ecosystem services. Since negative correlations usually exist between goods and services (e.g. [18,19]), humanmodified land-use areas would not be expected to produce levels of services simila (...truncated)