Holocene summer temperature reconstruction from plant sedaDNA and chironomids from the northern boreal forest

Mayfield, Roseanna J.; Rijal, Dilli P.; Heintzman, Peter D.; Langdon, Peter G.; Karger, Dirk N.; Brown, Antony G.; Alsos, Inger G.

Abstract

Climate-induced ecotonal shifts are expected to occur in the (sub)arctic and boreal zones in the coming decades. Understanding how these ecosystems have previously responded to climate change can provide greater insight into how ecosystems may develop under existing and future pressures. Here we present a Holocene record from Lake Horntjernet, a lake on the northern edge of the boreal forest in Northern Norway. We show vegetation development and landscape dynamics typical for Northern Fennoscandia during the Holocene. A plant sedaDNA record indicates rapid vegetation development following deglaciation with early arrival of Betula trees/shrubs. Pine forest was established by c. 8500 cal yr BP, and subsequent mid- to late Holocene vegetation assemblages are relatively stable. The aquatic ecosystem community is indicative of climatic change during the early Holocene, while strong coupling with changes in the catchment vegetation affects the water quality during the mid- and late Holocene. The chironomid record indicates lake water acidification following the establishment of pine forest and heathland. Different approaches for temperature reconstruction are calculated and the results are compared to better understand ecosystem-climate relationships and ecosystem resilience to climate change. Chironomid-inferred temperatures indicate early Holocene warming and late Holocene cooling, comparable to independent regional temperature trends. However, lake acidification impedes reliable reconstruction of chironomid-inferred temperatures in the mid-Holocene, a trend recognised in other boreal chironomid records. The application of sedaDNA plant-inferred summer temperature reconstruction is inhibited by the persistence of cold and warm tolerant species within the boreal pine forest. However, a trait-based approach reconstructed temperature trends that aligned with independent regional data. Thus, here we demonstrate the value of combined molecular and fossil-based proxies for elucidating the complex response of a boreal catchment to climate change.

Citation

Mayfield, R. J., Rijal, D. P., Heintzman, P. D., Langdon, P. G., Karger, D. N., Brown, A. G., & Alsos, I. G. (2024). Holocene summer temperature reconstruction from plant sedaDNA and chironomids from the northern boreal forest. Quaternary Science Reviews, 345, Article 109045. https://doi.org/10.1016/j.quascirev.2024.109045

• Journal Article Type: Article
• Acceptance Date: Oct 25, 2024
• Online Publication Date: Oct 30, 2024
• Publication Date: Dec 1, 2024
• Deposit Date: Nov 4, 2024
• Publicly Available Date: Nov 5, 2024
• Journal: Quaternary Science Reviews
• Print ISSN: 0277-3791
• Electronic ISSN: 1873-457X
• Publisher: Elsevier
• Peer Reviewed: Peer Reviewed
• Volume: 345
• Article Number: 109045
• DOI: https://doi.org/10.1016/j.quascirev.2024.109045
• Keywords: sedaDNA; Chironomids; Holocene; Palaeolimnology; Boreal; Temperature reconstructions; Trait-based reconstruction
• Public URL: https://nottingham-repository.worktribe.com/output/41542214
• Publisher URL: https://www.sciencedirect.com/science/article/pii/S027737912400547X?via%3Dihub
• Additional Information: This article is maintained by: Elsevier; Article Title: Holocene summer temperature reconstruction from plant sedaDNA and chironomids from the northern boreal forest; Journal Title: Quaternary Science Reviews; CrossRef DOI link to publisher maintained version: https://doi.org/10.1016/j.quascirev.2024.109045; Content Type: article; Copyright: © 2024 The Authors. Published by Elsevier Ltd.