There are several local emblematic tree species in the Park territory : beech, evergreen oak, sessile oak, chestnut ... These species structure several natural habitats whose ecological value is recognized at the European scale through the Habitats Directive and the French network of Natura 2000 sites. The objective of Natura 2000 sites is to maintain both human and economic activities while preserving these environments in the long run. The issue of climate change adds a layer of complexity to this balance. Will future generations still be able to admire these habitats on the territory and to benefit from their services?
As a pilot project, FORECCAST is studying the "Atlantic acidophilous beech forests with Ilex and sometimes also Taxus in the shrublayer" habitat, a Natura 2000 Habitat of Community Interest (HIC) also known through the code 9120. This beech forest facies is rather rare at the European scale. Its characteristics are an acidophilic flora and a strong presence of holly. In the Haut-Languedoc Regional Nature Park territory, it is one of the main Natura 2000 habitats with conservation and management stakes. The method we develop on this habitat will be transposable to other forest habitats.
The first step is to assess the presence and the conservation state of this habitat on the territory. We did inventories in about 30 plots in Natura 2000 sites and completed this data with a study of the database of the presence of this habitat in the plots of the French National Forest Inventory, thanks to a partnership with the IGN. Then we will apply to this data various scenarios of climate change to measure the extent of climate niche movements where habitat is present.
Repartition of the 9120 HIC (purple) within the Haut-Languedoc Regional Nature Park Natura 2000 sites network
Concerning in situ genetic adaptation capacity of trees, scientific knowledge is currently lackin to predict precisely the speed and extent of genetic adaptation. Nevertheless, it seems that beech could be much better armed to cope with climate change than originally thought. For the moment, we observed little decline for the species despite the extreme climatic events of recent decades. We also know that the beech populations present in the Park territory come from a Southern genetic lineage (Catalonia, Eastern Pyrenees, Black Mountain, South Massif Central and Southern Alps), so from a lineage a priori better suited to drought. This unique genetic resource could therefore play a very useful role in national or European strategies to promote the adaptation of beech.
The habitat studied in FORECCAsT is the "Atlantic acidophilous beech forests with Ilex and sometimes also Taxus in the shrublayer" habitat, which grows in a rather rainy Atlantic climate and higher than 500m. There are several indicator species for this habitat type, such as the blueberry (Vaccinium myrtillus) and the heath bedstraw (Galium saxatile). The 9120 characteristics are a forest dominated by the beech, accompanied by the warty birch and the rowan, where holly is very present, and with a dense herbaceous cover.
Atlantic acidophilous beech forest (Source : Johann Housset - PNRHL)
This habitat often appears where farm lands are abandoned. It can also be linked to a forest management with coppicing under a higher forest. These beech forests are often converted to coniferous forests, which is a threat for this habitat.
Within the FORECCAsT project, we will build vigilance maps for the beech, which generally structures the 9120 HIC. We will use the level of vigilance for the beech as a proxy of the level of vigilance to adopt for this habitat and will develop a user guide for our "FORECCAsT by BioClimSol" mobile application dedicated to this habitat, so that it will be possible to use the application for natural habitats. We will also test, in three 9120 HIC sites, several forest management procedures to allow the beech regeneration and the conservation of the Atlantic acidophilous beech forests.
Logo for our impending application