(MPI for Developmental Biology, Tübingen)
Ongoing global change and local land use management influence species and ecosystems. One of the most compelling types of evidence for this are shifts in the timing of phenological events. Plants, in particular, may respond with phenological shifts, e.g. via changes in the start of flowering, the time of peak flowering, and the total duration of the flowering period. Such shifts may have cascading effects on associated pollinators and other interacting organisms. Furthermore, long-term environmental change may affect the genetic diversity of plants and can thus have far-reaching consequences for evolution.
We combine field observations with mining of natural history collections and cutting-edge methods in herbarium genomics to investigate how land use and climate change affect the flowering phenology and genetic diversity of forest understory plants and whether there are long-term changes since the industrial revolution.
For this, we will focus on early-flowering herbs in the forest understorey, because these species have a short and distinct flowering period, and are therefore particularly amenable to studying phenology changes, including the effects of climate change and forest management on plant phenology.
Phenology I – Field surveys: Impact of forest management
While the impact of climate change on flowering phenology is well documented, knowledge about the impacts of other global change drivers, such as land use, is still scarce. In temperate forests, management changes alter tree species composition and stand structure, and therefore microclimate and light conditions and their seasonal patterns. Thus, forest management should affect the phenology of forest understory herbs. To test this, we record the phenology of 20 early-flowering herbs (see Fig. 1) on the 100 forest plots (EPs) of the Biodiversity Exploratories Hainich-Dün and Schwäbische Alb.
Phenology II – Herbaria: Impact of climate change
To infer potential long-term phenological changes we will compare the data of the contemporary plants in the Biodiversity Exploratories with data from herbaria collections from the same regions and species. The data from the herbarium surveys of historical specimens will be tested for long-term trends in flowering phenology and climatic correlates.
Genomics I – Method development
DNA retrieved from historical specimens (ancient DNA, aDNA) is usually degraded and highly fragmented, and has chemical modifications that differentiate it from fresh DNA. Due to these characteristics, RAD (Restriction site Associated DNA)-sequencing, which is based on enzyme-mediated DNA-restriction, is inadequate for aDNA. To be able to compare fresh and historical samples, we will refine a high-throughput genomic method, merging in-solution hybridization and RAD-sequencing for aDNA (hyRAD). The genetic analyses will be done for a subset of five species.
Genomics II – Genetic diversity
We will use this method to compare the genetic diversity of current forest understorey plants in the Biodiversity Exploratories to their ancestors from the same regions to assess temporal trends in genetic diversity.
Concluding, our project seeks to gather further insights into ecological as well as evolutionary responses of plants to anthropogenic environmental change that have far-reaching consequences for ecological communities and long-term evolution.