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Salinity shapes food webs in shallow lakes: implications for increasing aridity with climate change

Research output: Working paper/Preprint Working paperResearch

  • Nicolas Vidal
  • ,
  • Jinlei Yu, China
  • Maria Florencia Gutierrez, Denmark
  • Franco Teixeira-de Mello, Departamento de Ecología & Evolución, CURE-Facultad de Ciencias, Maldonado, Universidad de, Uruguay
  • U. Nihan Tavsanoglu, Denmark
  • Idil Çakıroğlu, Limnology Laboratory, Department of Biology, Middle East Technical University, Ankara, Turkey
  • Hu He, Denmark
  • Mariana Meerhoff, Denmark
  • Sandra Brucet Balmana, Denmark
  • Zhengwen Liu, Chinese Academy of Sciences, China
  • Erik Jeppesen
A reduction in runoff and higher evaporation rates are expected to occur towards 2050 in arid and semiarid regions of the world, resulting in a reduction of water level and salinization of inland waters. Besides the natural process of catchment erosion, human activities such as irrigation of crops may also increase salinization. Reduced biodiversity in freshwater systems is the most commonly reported effect of salinization, which may have implications for food web structure and likely for ecosystem functioning as well. The objective of the study was to analyze the effects of salinity on community and food web structure in 24 lakes along a wide salinity gradient, from freshwater (0.5 g L-1) to hypersaline lakes (115 g L-1), in a semiarid region in North West China. Fish, zooplankton and macroinvertebrate communities were sampled during July 2014 for determination of taxonomy and size structure and stable isotopes analysis. Based on the stable isotope data we calculated the food web Layman metrics: total area, nitrogen range, carbon range, centroid distance and also trophic position for each community and for the entire food web. We found a significant decline in the number of taxa of all communities analyzed and a reduction of food web complexity with enhanced salinity. Accordingly, the metrics used to describe the entire food web were all negatively related with salinity; however, when examining the food web of each single community the effect was not significant, implying that the species reduction at community level did not affect the trophic diversity. Our results suggest a negative effect of salinity not only on the structure but also on the functioning considering the entire food web of the studied lakes.
Original languageEnglish
Publication statusPublished - 2015

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