Can vegetation provide indications of ancient lake shorelines after more than one hundred years? A case study of Iskander-kul Lake, Tajikistan

Bioindication is a common approach to assess and evaluate environmental changes over both short or long periods of time. Here we attempt to highlight that vegetation can provide indications of the palaeoshoreline of Lake Iskander-kul, even after at least 150 years. It is an example of a dammed lake that was created by a huge mass rockfall as a result of a strong earthquake during the late Pleistocene. Applying the two way indicator species analysis (TWINSPAN) we found that the shrubby vegetation is the particular one that can still effectively thrive along the palaeoshoreline despite the lake downlift. Using the phi coefficient as a fidelity measure for certain vegetation type, we found, that Juniperus seravschanica, Lonicera seravschanica, Berberis integerrima, Seseli lehmannianum, Astragalus kabadianus and Ephedra intermedia have the highest indicator value for palaeoshoreline. Apart from the ancient palaeoshoreline, on the screes and slopes surrounding the lake, significantly different vegetation types developed on the screes and slopes dominated by steppe (Hyssopus servaschanica, Galium turkestanicum, Festuca valesiaca) and scree (Ferula foetidissima, Stipa drobovii or Ferula kuhistanica) vegetation types. Using the multivariate analysis (CCA) we show that the slope inclination and distance from the palaeoshorelines has considerable influence on species composition within the study plots.