Seed provenance matters — Effects on germination of four plant species used for ecological restoration

The use of local seed provenances is often recommended in restoration and habitat creation because they are thought to be better adapted to local habitat conditions. However, spatial scales and the degree of population differentiation are not well known and germination is often not included in comparisons between provenances. We analysed germination as a key trait of plant development in five provenances of four species used for ecological restoration on arable land (wildflower strips). Germination was tested under different conditions in growth chambers (early vs. late spring) and in the field (non-competition vs. competition). We also examined the contribution of non-genetic (maternal) effects to population differentiation. Large differences in germination traits were found between the provenances in growth chambers and in the field. The ranking was species-specific, but largely consistent across all tested environments. Local provenances did not generally exhibit higher germination percentages in the field relative to non-local provenances. Due to the high stability of germination traits across various environments, growth chamber tests provided a reliable prediction for provenance differences in the field. The differences among provenances seemed to be largely genetically determined as the inclusion of seed mass in the analysis to control for maternal effects did not decrease the degree differences between-provenance differences. In one species, however, non-genetic contributions to population differentiation were found by comparing F1 seeds grown under homogeneous conditions and original seed material. We conclude that potentially large between-provenance differences in germination traits need to be considered in ecological restoration projects,