Context Land use and land cover (LULC) change is a major part of environmental change. Understanding its long-term causes is a major issue in landscape ecology. Objectives Our aim was to characterise LULC transitions since 1860 and assess the respective and changing effects of biophysical and socioeconomic drivers on forest, arable land and pasture in 1860, 1958 and 2010, and of biophysical, socioeconomic and distance from pre-existing forest on forest recovery for the two time intervals. Methods We assessed LULC transitions by superimposing 1860, 1958 and 2010 LULCs using a regular grid of 1 9 1 km points, in a French Mediterranean landscape (195,413 ha). We tested the effects of drivers using logistic regressions, and quantified pure and joint effects by deviance partitioning. Results Over the whole period, the three main LULCs were spatially structured according to land accessibility and soil productivity. LULC was driven more by socioeconomic than biophysical drivers in 1860, but the pattern was reversed in 2010. A widespread forest recovery mainly occurred on steeper slopes, far from houses and close to pre-existing forest, due to traditional practice abandonment. Forest recovery was better explained by biophysical than by socioeconomic drivers and was more dependent on Electronic supplementary material The online version of this article (

NomenclatureFrench BDTFX flora nomenclature and European BDNBE bryophyte nomenclature Abstract Questions: How did past land use and conifer plantation affect understorey plant communities? What plant traits explain understorey vegetation response to agricultural past land use and coniferous plantation?Location: Forest of Orl eans (50 000 ha), Loiret, north-central France.Methods: Canopy cover, herb layer composition, litter and soil properties were measured in 80 100 m 2 plots sampled in plantations of Pinus sylvestris or P. nigra vs natural regenerations of Quercus petraea and Q. robur along a gradient of forest continuity (using historical maps and aerial photos from 1840, 1949 and 2006). We related 15 plant traits to past land use and tree species using RLQ and fourth-corner analyses.Results: The magnitude of past land use effect largely exceeded that of coniferous plantation. Post-agricultural forests, even 150 yr after afforestation, differed from ancient forests in soil properties (thinner humus layer, higher P content, higher pH and lower C/N ratio) and plant traits. Ancient forests hosted more forest core species, stress-tolerant, competitive species and bryophytes, but fewer ruderals, annuals/biennials, shrubs and trees and nutrient-demanding species, and had lower SLA and higher LDMC. Conifer plantations had a thicker humus layer, lower pH and higher C/N ratio than deciduous forests, and hosted more light-demanding species but less forest core species. Importantly, differences in soil and plant traits between conifer plantations and naturally regenerated deciduous stands were discernible in both recent and ancient forests, indicating that tree species lastingly influence ecosystem functioning.Conclusions: Past land use and coniferous plantation resulted in different understorey plant communities and traits under pine plantations and naturally regenerated oak stands. These differences were driven through soil acidification, litter decomposition rate, light conditions, canopy development, soil disturbance, stand management and dispersal and recruitment limitations. Coniferous plantations slowed down the recovery of post-agricultural forests to ancient deciduous forest conditions. Applying natural regeneration and favouring native deciduous tree species thus helps recreate or maintain ancient forest plant communities.

Maître de conférences en géographie, chercheur au Laboratoire d'observation des territoires (LOTERR, EA 7304, université de Lorraine), membre du conseil d'administration du Groupe d'histoire des forêts françaises, et de la commission de géographie historique du Comité national français de géographie (CNFG).

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