The similarity assessment of the macrophyte species composition between modern aquatic vegetation and subrecent pollen spectra of small lakes on the Valaam Island (Lake Ladoga)

Abstract

The article presents the results of studying the subrecent pollen spectra (SPS) and modern aquatic vegetation of four small lakes on Valaam Island (Lake Ladoga) – Germanovskoye, Zimnyakovskoye, Antonievskoye, and Vitalievskoye. We have established that the lakes are humus-rich reservoirs slightly overgrown with typical aquatic vegetation. The moss Fontinalis antipyretica Hedw. is the dominant species among submerged hydrophytes for lakes Germanovskoye, Antonievskoye, and Vitalievskoye. The dominant floating hydrophytes and helophytes are Nuphar lutea (L.) Smith for lakes Germanovskoye and Zimnyakovskoye; Nuphar lutea (L.) Smith, Nymphaea candida J. Presl., Potamogeton spp. for Lake Antonievskoe; Lemna minor L. and Hydrocharis morsus-ranae L. for Lake Vitalievskoye. The similarity of the macrophyte species composition between subrecent SPS and modern aquatic vegetation was analyzed. A high level of similarity was noted only for two lakes – Lake Antonievskoye with the qualitative Jaccard and Sorensen- Czekanowski indices at 0.60 and 0.75, respectively, and Lake Zimnyakovskoye with a high value of the quantitative Bray-Curtis index (0.76). However, almost all macrophyte species that dominated the overgrowth area during our study were present also in subrecent SPS, which suggests that top-core bottom samples quite adequately reflect modern aquatic vegetation. The results prove that studies of macrophyte pollen in the lake sediments hold promise for the study of modern lake ecosystems and for paleoreconstructions.