Seeds and seedlings are vulnerable stages in the life cycles of plants, and we can thus expect strong fitness consequences of environmental variability on these stages. In species with wide geographical or altitudinal distributions, the factors and processes controlling seedling mortality risk are unlikely to be constant throughout the species range.

In this project I will quantify the variation in seed dormancy levels along climatic gradients in Norway, and test some alternative hypotheses about climate effects on germination. I will do this in a phytotron germination experiment using seed batches from a large number of local populations, and relate this variability to local climatic variables describing the 'severity' and 'predictability' of the local climate.

While phytotron screening has the advantage of being efficient and enabling precise quantification and evaluation of between-population differences, it has the disadvantage of providing relatively unrealistic estimates of field behaviour. In a reciprocal seed burial experiment will be performed along an altitudinal gradient. Here I will test the effect of differences in dormancy levels and environmental conditions for seed survival for actual seed carry-over across years. By studying several species simultaneously, I hope to enable evaluation of differences in the relative magnitude of the responses in light of the species biology.

Nesheimhorgi

Tysnessåta

Davik, Bremanger

Four species, Veronica alpina (L.), Veronica fruticans (L.) Veronica officinalis (L.), and Veronica serpyllifolia (L.), will be used in this study. These species are in the same genus and have very similar overall morphology, seed production, and seed size, but differ in ecological preferences and geographical range.

Field work was carried out in 2002, when seeds from the four species were collected from 111 populations in Norway.

Laboratory work was carried out at the Millennium Seed Bank Project at RBG Wakehurst Place. Phytotron experiments were used to characterise germination responses of seed batches from the 111 local populations. Among-population variability will be related to variables describing the 'severity' and 'predictability' of the local climate.