The Reappearance of An Extremely Rare and Critically Endangered Nitella translucens (Charophyceae) in Poland

Abstract

We report the reappearance of the rare charophyte Nitella translucens in Poland. It was identified in the soft-water lobelian Lake Jeleń (North Poland) during 2013 and 2018 phytolittoral surveys. This species is considered critically endangered in various European countries and was previously classified as extinct inPoland. Its occurrence was confirmed using morphological and molecular data (ITS1-18S, ITS2-28S, rDNA, and rbcL). The N.translucens occupied ~20% of the lake bottom, at depths of 1.5-6.5m, water pH 7.5-8.6, conductivity of 59-66μS·cm-1 , and total nitrogen and phosphorus during growing season in the range of 1.1-1.4mg·L-1 and 0.07-0.1mg·L-1 , respectively. It co-occurred mainly with plant species typical for lobelia lakes: Isoetes lacustris, Littorella uniflora, and Myriophyllum alterniflorum, as well as Ceratophyllum demersum and Elodea canadensis, which are characteristic for eutrophicated waters. It appears that N.translucens may thrive in lobelia lakes during their transformation to more eutrophic states.