Search

SedaDNA reveals regional climate and bedrock nutrients as major drivers of terrestrial plant diversity in northern Fennoscandia., The effects of climate change on species richness are debated but can be informed by the past. Here, we generated a sedimentary ancient DNA dataset covering 10 lakes and applied novel methods for data harmonization. We assessed the impact of Holocene climate changes and nutrients on terrestrial plant richness in northern Fennoscandia. We find that richness increased steeply during the rapidly warming Early Holocene. In contrast to findings from most pollen studies, we show that richness continued to increase thereafter, although the climate was stable, with richness and the regional species pool only stabilizing during the past three millennia. Furthermore, overall increases in richness were greater in catchments with higher soil nutrient availability. We suggest that richness will increase with ongoing warming, especially at localities with high nutrient availability and assuming that human activity remains low in the region, although lags of millennia may be expected.

Understanding the dynamics of biodiversity in the past will contribute to a better informed inference of future biodiversity. Palaeoecological patterns in biodiversity are mainly preserved in natural archives such as lake sediments. Using ancient DNA from the sediment of 10 lakes from northern Fennoscandia, we analysed terrestrial plant diversity pattern for the entire Holocene, and how these patterns correspond to drivers of change such as temperature and biota. We modeled temporal trends in taxonomic richness and turnover using generalized additive models (GAM). We included delta oxygen isotope values from North Greenland Ice Core Project as a proxy for regional temperature, and the presence of dominant woody species as biotic drivers of terrestrial plant diversity. Results show a general tendency of an increase in species richness from the early Holocene onwards, but this pattern is asynchronous across the lakes, with some lakes having a peak in diversity in the mid-Holocene (8,000-6,000 cal. BP), late Holocene (~2,500 cal. BP), or in recent times. The turnover decreases in most of the lakes throughout the Holocene. Meanwhile, it consistently increases in a few lakes. With some exceptions, temperature and biotic variable differentially affects the richness and turnover across the lakes. Our study from multiple lakes and heterogeneous habitats may be able to identify the main drivers of past biodiversity changes in these systems. As a result, it may help us to understand the mechanisms of change so that the impacts of current climate change and biotic factors on biodiversity may be assessed. Author's list and affiliations:Dilli Prasad Rijal1, Peter D. Heintzman2, Youri Lammers2, Nigel Gilles Yoccoz1, Tony Gavin Brown2,3, Kelsey Lorberau1, Dorothee Ehrich1, Iva Pitelkova2, Tomasz Goslar4, Jostein Bakke5, Kari Anne Bråthen1, Inger Greve Alsos21Department of Arctic and Marine Biology, UiT - The Arctic University of Norway, NO-9037 Tromsø, Norway.2The Arctic University Museum of Norway, UiT - The Arctic University of Norway, NO-9037 Tromsø, Norway.3School of Geography and Environmental Science, University of Southampton, Highfield, Southampton, SO17 1BJ, UK.44Faculty of Physics, Adam Mickiewicz University, Poznan, Poland5Department of Earth Science, University of Bergen, 5020 Bergen, Norway

Genome skimming has the potential for generating large data sets for DNA barcoding and wider biodiversity genomic studies, particularly via the assembly and annotation of full chloroplast (cpDNA) and nuclear ribosomal DNA (nrDNA) sequences. We compare the success of genome skims of 2051 herbarium specimens from Norway/Polar regions with 4604 freshly collected, silica gel dried specimens mainly from the European Alps and the Carpathians. Overall, we were able to assemble the full chloroplast genome for 67% of the samples and the full nrDNA cluster for 86%. Average insert length, cover and full cpDNA and rDNA assembly were considerably higher for silica gel dried than herbarium-preserved material. However, complete plastid genomes were still assembled for 54% of herbarium samples compared to 70% of silica dried samples. Moreover, there was comparable recovery of coding genes from both tissue sources (121 for silica gel dried and 118 for herbarium material) and only minor differences in assembly success of standard barcodes between silica dried (89% ITS2, 96% matK and rbcL) and herbarium material (87% ITS2, 98% matK and rbcL). The success rate was &gt, 90% for all three markers in 1034 of 1036 genera in 160 families, and only Boraginaceae worked poorly, with 7 genera failing. Our study shows that large-scale genome skims are feasible and work well across most of the land plant families and genera we tested, independently of material type. It is therefore an efficient method for increasing the availability of plant biodiversity genomic data to support a multitude of downstream applications.