Population differentiation in timing of development in a forest herb associated with local climate and canopy closure
(English)Manuscript (preprint) (Other academic)
Our knowledge of how plant seasonal development is related to local versus larger-scale environmental variation is limited. We investigated differentiation in the timing of vegetative and reproductive development among populations of the forest herb Lathyrus vernus over different spatial scales. We predicted earlier development and shorter development time for populations from a colder, northern region compared to populations from a warmer, southern region. Also, we predicted earlier and shorter development within regions to be associated with colder temperatures and higher proportions of deciduous trees at their sites of origin. Lastly, we predicted that earlier flowering is strongly correlated with earlier start of development. To examine these predictions, we conducted a common garden study, and compared the development of 10 northern and 10 southern Swedish L. vernus populations. Start of development, development time and start of flowering did not differ between populations from the two regions in contrast to our prediction. Within the southern region, start of flowering was earlier in populations from colder sites, while start of development was earlier with colder temperatures within the northern region. Start of flowering occurred earlier in southern populations from sites with higher proportion of deciduous trees. Thus, the prediction for the timing of development within regions was partly confirmed. However, vegetative and reproductive development was not simultaneously influenced by temperature and proportion of deciduous trees within regions, possibly due to the negative correlation between vegetative growth and development time. This implies that earlier start of development or shorter development time not necessarily correspond to earlier start of flowering or vice versa. Overall, the results suggest that smaller scale effects within region, such as temperature and interspecific competition for light, was more important for the timing of development than the larger scale gradients between regions. Lastly, the population differentiation across gradients of temperature and proportion of deciduous trees implies that populations may adapt to long-term changes in light or climatic conditions, and differ in their short-term response to climate change.
reproductive development, vegetative development, local climate, forest herb, phenology, range margins, distributions
Research subject Plant Ecology
IdentifiersURN: urn:nbn:se:su:diva-129485OAI: oai:DiVA.org:su-129485DiVA: diva2:922554