Postglacial species arrival and diversity buildup of northern ecosystems took millennia

Abstract

What drives ecosystem buildup, diversity, and stability? We assess species arrival and ecosystem changes across 16 millennia by combining regional-scale plant sedimentary ancient DNA from Fennoscandia with near-complete DNA and trait databases. We show that postglacial arrival time varies within and between plant growth forms. Further, arrival times were mainly predicted by adaptation to temperature, disturbance, and light. Major break points in ecological trait diversity were seen between 13.9 and 10.8 calibrated thousand years before the present (cal ka BP), as well as break point in functional diversity at 12.0 cal ka BP, shifting from a state of ecosystem buildup to a state where most habitat types and biotic ecosystem components were in place. Trait and functional diversity stabilized around 8 cal ka BP, after which both remained stable, although changes in climate took place and species inflow continued. Our ecosystem reconstruction indicates a millennial-scale time phase of formation to reach stable and resilient levels of diversity and functioning.

Lateglacial and Early Holocene palaeoenvironmental change and human activity at Killerby Quarry, North Yorkshire, UK

“…Sequences were retained if they had an overall frequency of PCR repeats in samples at least twice as high as that in negative controls. Quantification of seda DNA data may not be straightforward as some taxa may be overrepresented in terms of sequence reads whereas using PCR repeats may underestimate abundance of the most abundant taxa (Alsos et al 2022). Thus, we present the data both as the proportions of PCR repeats and proportion of total identified reads.…”

“…Resulting barcodes were assigned to taxa using the ecotag program and four independent reference datasets. One reference contained arctic (Sønstebø et al 2010) and boreal (Willerslev et al 2014) vascular plants as well as bryophytes from the circumpolar region (Soininen et al 2015) (ArcBor-Bryo, n = 2280 sequences of which 1053 are unique), one the NCBI nucleotide database (January 2021 release), and finally the PhyloNorway p6loop database (Alsos et al 2022). The resulting identifications were merged and filtered, retaining barcode sequences if they were identified to >98% in at least two reference sets and had at least 10 reads across the entire dataset.…”

CHELSA-TraCE21k – high-resolution (1 km) downscaled transient temperature and precipitation data since the Last Glacial Maximum

“…Transient long-term climatic data have a wide range of possible applications, ranging from population genetics (Leugger et al, 2022;Yannic et al, 2020), community ecology (Staples et al, 2022), and biodiversity buildup (Garcés-Pastor et al, 2022;Alsos et al, 2022) to evolutionary biology (Cerezer et al, 2022), just to name a few. Here we use one application in paleoecology as a plausibility test to additionally check if the transient CHELSA-TraCE21k data can reliably detect known LGM refugia of plant species.…”

Environmental DNA of aquatic macrophytes: the potential for reconstructing past and present vegetation and environments

“…For individual site reconstructions, we did not merge samples into time slices before plotting the distribution of traits values as their respective proportions across replicates through time. Additionally, we checked for potential correlations between species traits and their first recorded and estimated arrival dates in the region (Alsos et al, 2022), to see if some traits could explain the arrival of aquatic macrophytes. We further evaluated how the composition of aquatic taxa was affected by our six selected traits, using multivariate analysis.…”