Past land use is an important factor determining vegetation in temperate deciduous forests. Little is known about the duration of these impacts on vegetation but especially on the seed bank. This study assessed whether soil characteristics remain altered 1600 years after human occupation and if this has led to persistent differences in forest plant communities and their seed bank in particular.
Compiègne forest is located in northern-France and has a history of continuous forest cover since the end of Roman times. Twenty-four Gallo-Roman and 24 unoccupied sites were sampled and data were analysed using paired sample tests to investigate whether soil, vegetation and seed bank differed significantly.
The soil was persistently altered on the Gallo-Roman sites resulting in elevated phosphorus levels and pH (dependent on initial soil conditions) which translated into increased vegetation and seed bank species richness. Though spatially isolated, Gallo-Roman sites supported both a homogenized vegetation and seed bank. Vegetation differences were not the only driver behind seed bank differences. Similarity between vegetation and seed bank was low and the possibility existed that agricultural ruderals were introduced via the former land use.
Ancient human occupation leaves a persistent trace on forest soil, vegetation and seed bank and appears to do so at least 1600yr after the former occupation. The geochemical alterations created an entirely different habitat causing not only vegetation but also the seed bank to have altered and homogenized composition and characteristics. Seed bank differences likely persisted by the traditional forest management and altered forest environment.