Negative evidence of local adaptation to the establishment conditions in a perennial herb

The differential adaptation of populations of the same species to their local environmental conditions through divergent selection, known as local adaptation, is a key step in the process of diversifica- tion of species. Here, we explore the local adaptation of the perennial mountain herb Helleborus foetidus to variable environmental conditions of seedling emer- gence and establishment at two different spatial scales (habitats and regions) with special attention to the role of physical and chemical soil properties. The possi- bility of local adaptation was evaluated under the ‘‘local versus foreign’’ and the ‘‘home versus away’’ criteria. Reciprocal sowing experiments were carried out by cross-sowing seeds among habitats and regions, controlling for maternal effects by means of seed mass, and recording seedling emergence and survival. Several topsoil properties were measured linked to each sowing point. Only partial patterns of local adaptation were found, which were insufficient to eventually state the existence of local adaptation at any spatial scale or under any criteria assessed. Here, we discuss how soil properties and selection on seed size may be related to the non-achievement of local adaptation criteria. Negative evidence of local adap- tation seems to be due to a congruency in the selective pressures exerted by the different soil environments on seedling emergence and survival