Recruitment and growth of herb‐layer species with different colonizing capacities in ancient and recent forests

Abstract

Abstract.Forest herbs differ greatly in their capacity to recolonize secondary forests established on former agricultural land. We investigated whether interspecific differences in recruitment or growth can account for differences in colonization success. Seeds and adults of two species with limited colonization capacities (Anemone nemorosaandPrimula elatior) and two species with high colonization capacities (Ranunculus ficariaandGeum urbanum) were introduced in ancient and recent forest sites within the Muizen forest (Belgium). At all sites, half of the plots were also cleared of above‐ground vegetation.Seedling establishment was similar in recent and ancient forest sites. However, both the number and subsequent survival of seedlings of the two hemicryptophytes (G. urbanumandP. elatior) were significantly lower when vegetation cover was present, while seedling number and survival of the two geophytes (A. nemorosaandR. ficaria) were less influenced by vegetation cover. Adult performance ofP. elatiorandG. urbanumwas significantly better in the nutrient enriched recent forest stands and in the absence of vegetation cover. Performance ofA. nemorosaandR. ficariawas not affected by any of these factors. We conclude that the extent of seed limitation is probably the main cause for the different colonization capacities of the species investigated.