Migration of herbaceous plant species across ancient-recent forest ecotones in central Belgium

1 We studied the migration of forest plant species using their percentage c over and frequency in 197 plots distributed over 26 transects across ecoton es between ancient and recent deciduous forests in the Meerdaal forest comp lex in central Belgium. The recent forest stands varied in age between 36 a nd 132 years, and all occurred on silty, well-drained soils. 2 The total cover, number and diversity of field layer species did not diff er significantly between ancient and recent forest stands. 3 The number and cover of the ancient forest plant species and of ant-dispe rsed species correlated positively with the age of the recent forest and ne gatively with both the duration of its former agricultural land use and the distance to the ancient forest. This implies a slow colonization of the re cent forest stands by these species; all species were, however, able to mig rate across the ecotones. 4 The cover of four species (Anemone nemorosa, Lamium galeobdolon, Convalla ria majalis and Polygonatum multiflorum) declined along the transect, sugge sting that they are limited by seed dispersal. Their colonization rates, ca lculated from the occurrence of the farthest individual, ranged from < 0.05 to 1.15m year(-1) and for other measures from < 0.05 to 0.65 m year(-1). A nemone and Lamium appeared to colonize the recent forest by establishment o f isolated individuals, while Polygonatum and Convallaria expanded populati ons from existing patches on the border between ancient and recent forest. 5 Several forest species were able to colonize the recent forest rapidly, w here some of them even reached a higher abundance, due to the increased ava ilability of colonization sites with a higher nutrient content and a thinne r organic layer.