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Research article2024Peer reviewedOpen access

Restoring charophytes is still a challenge: A call for developing successful methods

Faithfull, C. L.; Tamarit, E.; Nordling, P.; Kraft, E.

Abstract

Submerged aquatic vegetation, and especially charophytes, which are an important habitat for many species, have declined in the Baltic Sea due to changes in light climate, eutrophication and physical disturbance. Physical disturbance in the form of small-scale dredging activities is commonplace in Sweden due to land uplift, but causes fragmentation of coastal habitats. Here we test three planting methods for restoration of the charophyte Chara aspera on an area of deposited sediment, and a single method for restoration of C. tomentosa in a dredged area. We found that none of the planting methods tested was more successful than natural recolonization of C. aspera on the deposited sediment. C. tomentosa planting was unsuccessful in the dredged area and was likely outcompeted for light by taller species. The C. aspera meadow was resilient to smaller disturbances, as experimental removal of up to 2.5% of C. aspera and sediment from the donor area did not reduce C. aspera coverage a month after removal. Even after an uncontrolled event that removed up to 50% of C. aspera in the experimental plots, C. aspera coverage had returned to pre-removal levels a year after the disturbance. We suggest future restoration experiments test transplanting sediment rich in oocytes and bulbils into areas with suitable light climates and low competition with other species. Restoration efforts are costly and highly uncertain of success, therefore we recommend discontinuing dredging activities in charophyte meadows to protect this important habitat.

Keywords

Charophytes; Restoration; Chara aspera; Dredging; Dumping; Planting; Recolonization

Published in

Aquatic Botany
2024, Volume: 193, article number: 103777Publisher: ELSEVIER

    UKÄ Subject classification

    Environmental Sciences
    Ecology

    Publication identifier

    DOI: https://doi.org/10.1016/j.aquabot.2024.103777

    Permanent link to this page (URI)

    https://res.slu.se/id/publ/131812