Hedges play a key role in agricultural landscapes. Beyond their function as ecological corridors within the green frame, they constitute an important refuge for biodiversity and provide numerous ecosystem services (e.g. protection of crops/livestock, pest regulation, protection of water resources, erosion and flood control, wind protection).
In the current context of climate change, hedgerow structures (and more generally trees outside forests) represent a significant carbon sink, through their aerial and root biomass and their ability to sequester carbon in soils, and thus constitute one of the recognized levers for mitigating global warming. However, we have observed a sharp decrease in the surface area of hedges over the last few decades, particularly following the consolidation of agriculture, which has led to a massive uprooting of hedges to increase the surface area of plots. Today, European and national environmental public policies support the protection and replanting of hedges (see the "Planting hedges! "program, national "Low Carbon" strategy, Hedge Label), but there is no solution to evaluate the impact of these policies.
The IGN recently received financial support from the Ministry of Agriculture and Food, the Ministry of Ecological Transition and the OFB (French Office for Biodiversity) to set up a national system for monitoring bocages. This has enabled the creation of a reference system ("BD BOCAGE"). Nevertheless, this data is not complete enough and its update is not envisaged today.
In this context, the EagleHedges project has the ambition to answer the following two major challenges:
- The implementation of an operational service to extract the surface and linear hedges of a territory, in order to monitor their evolution and update the BD BOCAGE to support the implementation of national policies of agroecological transition. This service will be based on the use of space or airborne remote sensing images at very high spatial resolution (0.2-6m) and 3D models for the detection of hedges.
Hedge extraction layer (©UMR Dynafor) from satellite images (© DigitalGlobe).
- The development of an operational tool to characterize hedgerows from a morphological, structural and functional point of view in order to evaluate their roles and ecosystem services (carbon sequestration potential in particular). This open-source tool will integrate standardized business indicators, created to meet the specific needs of ongoing national programs (BD BOCAGE, Label Haie, Label Bas Carbone) or on project territories.
Characterization of the roles of the bocage network. © UMR DYNAFOR
EagleHedges is the result of a collaboration between private (TerraNIS), research (DYNAFOR/INRAE/INP) and public (IGN, OFB) actors and a network of professionals of the bocage environment (AFAC).
TERRITORIES FOR EXPERIMENTATION
- Areas have been pre-identified: Pyrenees-Gascony Workshop Area (PYGAR), Haute-Garonne department, Aude department.
- Experimentation territories will be co-defined with the OFB and AFAC partners at the beginning of the project.
- Various scales, from the group of farms to the department will be covered.
- Pleiades (multispectral bands + derived Digital Surface Models)
- BD Ortho IGN + Digital Surface Model/Digital Terrain Model IGN
- LiDAR HD IGN
- IGN BD BOCAGE
- OFB and AFAC field survey data
RESULTS - FINAL PRODUCTS
- Layer of surfaces and hedge lines
- HedgeTools software (toolbox or QGIS plugin) for the calculation of indicators
- 2D/3D indicators to evaluate the multifunctionality of hedges