EGU2020-3011, updated on 12 Jun 2020
https://doi.org/10.5194/egusphere-egu2020-3011
EGU General Assembly 2020
© Author(s) 2020. This work is distributed under
the Creative Commons Attribution 4.0 License.

Recent ecological trajectory of lake Taihu and land-use history reconstructed from lake sediment DNA

Charline Giguet-Covex1, Qi Lin2, Ludovic Gielly3, Fabien Arnaud1, and Ke Zhang2
Charline Giguet-Covex et al.
  • 1Environnement, Dynamique, Territoires de Montagne (EDYTEM), CNRS, Université Savoie Mont Blanc, France
  • 2Nanjing Institute of Geography and Limnology, China
  • 3Laboratoire d’Ecologie Alpine (LECA), CNRS, Université Grenoble-Alpes, France

More than 80% of shallow lake ecosystems in the Yangtze floodplain suffer significant disturbances from the 50’s, especially eutrophication. These environmental degradations and subsequent loss of services are related with the important and rapid development of the agriculture, industry, urban areas and the population boom in the region. Lake Taihu is one of the largest lakes of the floodplain and represents an important water resource (for drinking and fishing) for the population of the two big cities on the lake shore. This lake experimented two shifts toward the degradation of the trophic state: one in the 50-60’s and a second in 80’s.

In order to document the causes of these ecological shifts, we applied the DNA metabarcoding approach on lake sediments and focused on plants as proxy of land use. Whereas this proxy has been successfully applied in many lakes over the world, it has never been tested in large shallow lakes and not in China either.

We show important changes in land use in 50’s and 80’s related with agricultural developments (i.e. intensification) and urban expansion, respectively. In fact, in the 50’s crop plants are increasing (rapeseed and/or cabbage, rice and/or wheat, barley and Poaceae) whereas in 80’s, we record the development of several plants associated to gardens (e.g. ornamental species). Moreover, this last period is characterised by the presence of trees mostly cultivated along stream banks to protect dikes against erosion. Between the 80’s and the years 2000, the plant diversity recorded in the sediment strongly increase, which may be due to higher detrital inputs (i.e. more efficient DNA transfer). The timing in land-use changes corresponds to the main shifts in lake trophic state.

How to cite: Giguet-Covex, C., Lin, Q., Gielly, L., Arnaud, F., and Zhang, K.: Recent ecological trajectory of lake Taihu and land-use history reconstructed from lake sediment DNA , EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-3011, https://doi.org/10.5194/egusphere-egu2020-3011, 2020

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  • CC1: Comment on EGU2020-3011, Lydia Mackenzie, 05 May 2020

    Great to see the Taihu lake sediment DNA results in collaboration with NIGLAS! 

    • AC1: Reply to CC1, Charline Giguet-Covex, 05 May 2020

      Nice to meet you Lydia,

      I found your paper from northeastern china (in Paleo3 2018). It is very interesting :-)

      What is your speciality? Did you performed the pollen analyses on these three chinese lakes?

      What do you think about our DNA results from Taihu? It is the first time that we apply plant DNA analyses in such large and shallow lake and in China, so I would be happy to have your mind.

      many thanks !