Response of Submerged Macrophyte Communities to External and Internal Restoration Measures in North Temperate Shallow Lakes

Frontiers in Plant Science

Andrea Kelly¹  Wolf M. Mooij²  Ruurd Noordhuis³  Geoff Phillips⁴  Nigel Willby⁴  Jacqueline Rücker⁵  Hans-Heinrich Schuster⁶  Klaus van de Weyer⁷  Arno Waterstraat⁸  Carl D. Sayer⁹  Irmgard Blindow^1,10  Lars-Anders Hansson^1,11  Thomas A. Davidson^1,12  Marta M. Alirangues Nuñez^1,13  Jan Köhler^1,13  Sabine Hilt^1,13  Mikael Gillefalk^1,13  Sven Teurlincx^1,14  Ellen van Donk^1,14  Elisabeth S. Bakker^1,14  Timm Kabus^1,15  Jan H. Janse^1,16  Martin Søndergaard^1,17  Erik Jeppesen^1,17  Torben L. Lauridsen^1,17  Annette B. G. Janssen^1,18 

[1] 0Broads Authority, Norwich, United Kingdom;1Department of Aquatic Ecology and Water Quality Management, Wageningen University and Research, Wageningen, Netherlands;2Deltares, Delft, Netherlands;3Biological and Environmental Sciences, University of Stirling, Stirling, United Kingdom;4Department of Freshwater Conservation, Brandenburg University of Technology Cottbus-Senftenberg, Senftenberg, Germany;5Niedersächsischer Landesbetrieb für Wasserwirtschaft, Küsten- und Naturschutz, Sulingen, Germany;6Lanaplan, Nettetal, Germany;7Gesellschaft für Naturschutz und Landschaftsökologie, Kratzeburg, Germany;8Department of Geography, Environmental Change Research Centre, University College London, London, United Kingdom;Biological Station of Hiddensee, University of Greifswald, Greifswald, Germany;Department of Biology, Lund University, Lund, Sweden;Department of Bioscience, Aarhus University, Silkeborg, Denmark;Department of Ecosystem Research, Leibniz-Institute of Freshwater Ecology and Inland Fisheries, Berlin, Germany;Departmnet of Aquatic Ecology, Netherlands Institute of Ecology (NIOO-KNAW), Wageningen, Netherlands;Institute of Applied Freshwater Ecology, Seddiner See, Germany;Netherlands Environmental Assessment Agency (PBL), Den Haag, Netherlands;Sino-Danish Centre for Education and Research, University of Chinese Academy of Sciences, Beijing, China;Water Systems and Global Change Group, Wageningen University and Research, Wageningen, Netherlands;

关键词: aquatic plants;    biomanipulation;    eutrophication;    lake restoration. nutrient load reduction;    PCLake;    plant traits;   

DOI  :  10.3389/fpls.2018.00194

来源: DOAJ

【 摘 要 】

Submerged macrophytes play a key role in north temperate shallow lakes by stabilizing clear-water conditions. Eutrophication has resulted in macrophyte loss and shifts to turbid conditions in many lakes. Considerable efforts have been devoted to shallow lake restoration in many countries, but long-term success depends on a stable recovery of submerged macrophytes. However, recovery patterns vary widely and remain to be fully understood. We hypothesize that reduced external nutrient loading leads to an intermediate recovery state with clear spring and turbid summer conditions similar to the pattern described for eutrophication. In contrast, lake internal restoration measures can result in transient clear-water conditions both in spring and summer and reversals to turbid conditions. Furthermore, we hypothesize that these contrasting restoration measures result in different macrophyte species composition, with added implications for seasonal dynamics due to differences in plant traits. To test these hypotheses, we analyzed data on water quality and submerged macrophytes from 49 north temperate shallow lakes that were in a turbid state and subjected to restoration measures. To study the dynamics of macrophytes during nutrient load reduction, we adapted the ecosystem model PCLake. Our survey and model simulations revealed the existence of an intermediate recovery state upon reduced external nutrient loading, characterized by spring clear-water phases and turbid summers, whereas internal lake restoration measures often resulted in clear-water conditions in spring and summer with returns to turbid conditions after some years. External and internal lake restoration measures resulted in different macrophyte communities. The intermediate recovery state following reduced nutrient loading is characterized by a few macrophyte species (mainly pondweeds) that can resist wave action allowing survival in shallow areas, germinate early in spring, have energy-rich vegetative propagules facilitating rapid initial growth and that can complete their life cycle by early summer. Later in the growing season these plants are, according to our simulations, outcompeted by periphyton, leading to late-summer phytoplankton blooms. Internal lake restoration measures often coincide with a rapid but transient colonization by hornworts, waterweeds or charophytes. Stable clear-water conditions and a diverse macrophyte flora only occurred decades after external nutrient load reduction or when measures were combined.

【 授权许可】

Unknown