Suitable plant combinations for ecological floating beds in eutrophic subtropical coastal wetlands under different salin

  • PDF / 2,380,071 Bytes
  • 12 Pages / 595.276 x 790.866 pts Page_size
  • 62 Downloads / 172 Views

DOWNLOAD

REPORT


ORIGINAL PAPER

Suitable plant combinations for ecological floating beds in eutrophic subtropical coastal wetlands under different salinities: experimental evidences J. C. Lyu1,2 · G. H. Lin1,2 · Z. Y. Fan3 · W. X. Lin3 · Z. Dai2 Received: 8 January 2020 / Revised: 24 April 2020 / Accepted: 18 May 2020 © Islamic Azad University (IAU) 2020

Abstract The ecological restoration of coastal wetlands to remediate eutrophication has attracted attention worldwide. Although ecological floating beds have been widely used in freshwater ecosystems, selecting suitable plant combinations in coastal ecosystems where salinity changes dramatically remains a challenge. In this study, a controlled experiment was conducted to explore suitable plant species combinations with high purification efficiency and landscape aesthetics for ecological floating beds under different salinities. A total of seven plant combinations were planted in ecological floating beds in artificial eutrophic water with either freshwater or saline water (about 15 psu). After 6 weeks of growth, the concentration of nitrogen and phosphorus in water decreased significantly. Based on water purification efficiency, plant growth performance and landscape aesthetics, the combination with two freshwater plant species (Lythrum salicaria + Phragmites australis) and one mangrove species (Kandelia obovata) was identified as the optimal choice for low-salinity wetland habitats, whereas the combination with two mangrove species (Kandelia obovate + Bruguiera gymnorhiza) and one freshwater plant species (Canna indica) was the best for brackish wetland environments. With the proper designs, the ecological floating beds containing these plant combinations can be applied to the wetland restoration projects for both purification and beautification of coastal wetlands under the frequent influence of eutrophic and tidal water. Keywords  Coastal wetland restoration · Landscape aesthetics · Plant growth performance · Plant selection · Water purification

Introduction Located in a land–ocean ecotone where human activities are highly concentrated, coastal wetlands around the world have undergone serious degradation (Guo et  al. 2014; Sun et al. 2015). Wetlands worldwide are increasingly affected by both natural and human factors, including land Editorial responsibility: J. Aravind. * G. H. Lin [email protected] 1



Department of Earth System Science, Tsinghua University, Beijing 100084, China

2



Laboratory of Stable Isotope and Gulf Ecology, Tsinghua Shenzhen International Graduate School, Shenzhen 518055, Guangdong, China

3

Fujian Spring Ecological Technology Co., Ltd., Zhangzhou 363000, Fujian, China



reclamation, biological invasion, wastewater discharge, overfishing, etc. Among them, industrial, agricultural and aquaculture pollution emissions are the main causes of wetland degradation in typical estuaries and bay areas (Shen et al. 2019). In China, for example, about 60% of the coastal waters have been polluted by excessive nutrient input, and about 10% of these