Rapid evolution in novel environments: a multispecies approach
Final Report Abstract
One of the main issues in the current conservation science is whether organisms will be able to adapt to the rapidly changing environment. This is especially valid for plants, because their ability to migrate is limited. To predict plant adaptation, we need to understand contemporary evolution. We have relatively good knowledge on rapid evolution of several model plants, but for a general picture, we need information across a large number of non-model plant species. Here, we carried out a project focused on rapid evolution in 19 common grassland species cultivated for seed production for ecosystem restoration. Specifically, we studied whether cultivation conditions alter properties of the cultivated populations. This system is excellent to answer not only general questions about rapid evolution across species, but also to reveal how the cultivation process alters properties of the wild plants. Since restoration efforts are increasing globally, agricultural seed propagation in mandatory to cover the demand. Yet, it is crucially important to understand whether the cultivation process itself does not compromise adaptation of the plants to the natural environment. We obtained wild collected seed and up to four consecutive generations in cultivation of 19 species from two seed producers, one located in Germany and one in Austria. We germinated the seeds and carried out a series of common garden experiments to test for genetic differentiation between wild and cultivated generations and their stress tolerance. Additionally, we used genotyping by sequencing to reveal possible genetic drift and loss of whole-genome genetic diversity. Overall, we detected that cultivated generations were evolving towards larger sizes – they produced more biomass, were taller and had more inflorescences. On the other hand, the variation in several traits was decreasing across the cultivated generations, which was especially apparent in flowering phenology. As the whole-genome variation was higher in cultivated generations than in the wild collection, the loss of phenotypic variation was rather due to selection than genetic drift. Interestingly, the same species cultivated by two different seed producers did not show similar evolutionary change, suggesting that the evolutionary changes are not driven by species traits. More likely, the changes depend on cultivation process and individual decisions like e.g. the timing of seed harvest. While the detected evolutionary changes corresponded to the theoretical predictions, the effect sizes within individual species were mostly small and often non-significant. When exposed to stress, plants from farm-propagated seed mostly performed equally well as plants from wildcollected seed, with the exception of drought stress in one of the six tested species. This suggests that the cultivation process does not compromise the quality of the restoration seed. However, the detected changes linearly increased across generations. While the difference between wild and cultivated plants was small after 3-4 generations, it may become substantial when the seed stock should be cultivated across many generations. For that reason, it is a good strategy to introduce a cap on the maximum number of generations for which the seed stock can be propagated without replenishing from wild collection.
Publications
- (2021) Plant provenance affects pollinator network: Implications for ecological restoration. Journal of Applied Ecology
Bucharova A., Lampei C., Conrady M., May E., Matheja J., Ott D.
(See online at https://doi.org/10.1111/1365-2664.13866)
