Abstract
Mountains provide various ecosystems services (ES) through their diverse habitats and associated functions. These ES are impacted by ongoing land-cover changes in addition to climate change, and therefore vary over time. Taking into account their historical trajectory is necessary to understand both the current and future provision of ES. Temporal changes in ES have been widely studied in relation to land-cover changes through photographic and cartographic analyses covering few decades. However, this timescale is not sufficient to study ES sustainability, synergies, interactions, and time lags. Our study aims at reconstructing ES trajectories in relation to past land cover inferred from pollen-based reconstruction available for the last 200 years in the Bassiès valley. As this valley witnessed expansion of dwarf shrub species on grassland areas, due to the abandonment of pastoral activities, we hypothesized that the diversity of ES will reach its maximum at the tipping point of the land-cover transition followed by a decrease when heathland has replaced most grassland. We first characterized ES produced within each current land-cover type and combined these results with data on land-cover changes during the past 200 years. Our results do not show any significant change in ES diversity through time but clearly show a transition of ES associated with the transformation of grassland into heathland. More specifically, forage, species of conservation concern as well as many regulating services decreased with the decline of grassland, whereas pollination potential, esthetic value and plant picking increased with the expansion of heathlands (Rhododendrons in particular). Further research will explore the link between these changes and people’s needs and demands.