SPICE III Indonesia: TIMES – Terrestrial Influences on Mangrove Ecology and Sustainability of their resources - Carbon sequestration as a function of land use change in mangroves
|Supervisor:||Dr. Jens Boy, Dr. Robert Mikutta, Prof. Dr. Georg Guggenberger|
|Researcher:||Christian Weiss, Joanna Weiss|
|Funded by:||Bundesministerium für Bildung und Forschung (BMBF)|
[Translate to Englisch:] Major goal
This project aims at understanding the processes of carbon (C) sequestration in representative mangrove ecosystems in Indonesia (Segara Anakan Lagoon, Java, Togian Islands, Sulawesi, Berau, Kalimantan) as a function of mangrove conversion, in order to develop and test an easy-to-use tool for pricing of C related environmental services (CRES) in REDD and PES schemes. We will investigate into the C sequestration potential of mangrove by linking C stocks to sources, composition, and turnover of organic matter (OM) species in soil. Furthermore, we aim to clarify to which extent these functions are triggered by plant and microorganisms (bacteria and fungi) species composition in pristine and used (including completely deforested) mangroves. This process-based understanding of utilization thresholds is a prerequisite for successful future management scenarios dealing with C sequestration in mangrove ecosystems. Moreover, it will be tested whether identification of aboveground species composition could act as a valid indicator for CRES, both in economically based decision making on broader scale and local cost-efficient monitoring of the consecutive provision of CRES.
Relevance to science policy
The proposed research project is incorporated into the third phase of the Indonesian – German SPICE programme and assesses the C sequestration and ecosystem functionality of human-impacted coastal mangroves. Resource exploitation (timber supply, fishery, shrimps production) has caused severe losses of important ecosystem functions (e.g. biodiversity, C-sequestration) within the coastal areas. Obtaining measures for degrading coastal environments will help mitigate the negative feedbacks on ecosystem sustainability and social welfare. The proposed activities are also in line with major objectives of other international research and assessment programmes of the Earth System Science Partnership (ESSP), i.e. DIVERSITAS (International Programme of Biodiversity Science), IGBP (International Geosphere-Biosphere Programme, there, in particular LOICZ II (Land-Ocean Interactions in the Coastal Zone)) and IHDP (International Human Dimensions Programme on Global Environmental Change).
Scientific and/or technical objectives
In the frame of this project we will investigate C sequestration and its underlying mechanisms in mangrove forest ecosystems under different land use regimes. Carbon stocks and stabilization mechanisms will be studied along management gradients, which involve different stages of anthropogenic use. These include pristine/low-impact mangrove forest, two degradation stages, i.e., mangrove forest used for local timber supply, and an ex-mangrove used for shrimp production, as well as one restoration stage, i.e., a reforested mangrove stand. Incorporation of a reforested mangrove site will enable us to test whether mangrove ecosystems principally can regain original functionality with regard to biogeochemical processes including C sequestration, or whether the anthropogenic impact causes long-term disturbance of the mangrove ecosystem beyond reforestation. The following hypotheses will be tested:
- The net rate of C sequestered in mangrove soils is controlled by sedimentation of estuarine and marine suspended C including phyto- and zooplankton, autochthonous plant litter production, and the decomposition of the different C sources.
- The amount of C sequestered in mangrove soils and the controlling microbial processes strongly depend on the intensity of the anthropogenic impact. Land use reduces microbial diversity and C sequestration of mangroves by reversing the ecosystem from a C sink to source.
- The amount and stability of C sequestered in pristine and converted mangrove soils depend on the partitioning of C into OM fractions of different stability, i.e., labile particulate OM (POM) versus more stable mineral-associated OM (MOM).
- Within MOM and POM, the contribution of differently stable biocompounds determines their vulnerability for getting degraded upon land use changes.
The objective of this study regarding PES and REDD is to test to which extent these complex mechanisms can be linked to more accessible ecosystem parameters (e.g. fauna and flora composition or distance to tributaries), in order to set up a simple decision tool (in cooperation with SP8) allowing for rough and cost-effective estimation of C-sequestration potential on a solid, science-based, and process-oriented ground.