First records and molecular confirmation of invasive species Elodea nuttallii (Planch.) H.St.John, 1920 in Lithuania

Alien aquatic plant species have significant ecological and economic impacts on freshwater ecosystems and are mentioned amongst the major threats to aquatic biodiversity. Detection of alien species at the beginning of invasion can help avoid their spread and prevent negative impacts on aquatic ecosystems. This study presents the first records of invasive species Elodea nuttallii in Lithuania. This species was found in three localities of the Nemunas River (southern Lithuania) in 2020 and 2021. The localities were mapped using system grid cells arranged based on geographical coordinates with sides of 6′ latitude and 10′ longitude. The habitat characteristic and associated species were presented. The identity of Elodea nuttallii was confirmed using a molecular method (sequencing of two regions ITS and psbE-petL). The molecular analysis was effective in supporting the identification of individuals collected in the early stages of growth. We suppose that Elodea nuttallii may be more widespread in the region of north-eastern Poland, north-eastern Belarus and southern Lithuania and will continue to spread north and northeast directions. The expansion of Elodea nuttallii can have a negative impact on valuable natural habitats, particularly on protected throughout Europe water courses with the Ranunculion vegetation

Assessment of Anthropogenic Impacts on the Genetic Diversity of <i>Phragmites australis</i> in Small-River Habitats

Common reed is often used as a model plant to study the anthropogenic impacts on ecosystems at local and global scales. As a community-forming species, it is directly exposed to the impacts of human activities on the ecosystem. The aim of our study was to evaluate the patterns of genetic diversity in common reed stands located in habitats that are differently affected by anthropogenic factors. We studied whether riverbed modifications, land cover in the neighborhood of the stand and the chemical and physical parameters of the river water affect the genetic diversity of P. australis at the studied sites. Using DNA fingerprinting, we genotyped 747 plants from 42 sites located in 16 small Lithuanian rivers. Bayesian clustering and principal coordinate analysis revealed two main gene pools at the population (river) level. At the site level (i.e., considering all sites independently of their rivers), polymorphism was high even between sites in the same river. Our study revealed a negative relationship between the concentration of nitrogen compounds and the genotypic richness of P. australis populations. We did not find any correlations between the other chemical parameters of the water and the parameters of the genetic diversity. Additionally, there were no genetic differences between sites in modified and unmodified river sections or between sites that differed in land cover type in the neighborhood of the stand

Genetic diversity of aquatic Ranunculus ( Batrachium, Ranunculaceae) in one river basin caused by hybridization

Aquatic Ranunculus (sect. Batrachium) include homophyllous and heterophyllous plants. The development of floating leaves may be induced by genetic mechanisms or/and environmental conditions and this fact complicates the morphologically based identification of species. DNA-based studies provide the opportunity to expand the knowledge of this complicated group. We studied heterophyllous Ranunculus with well-developed capillary and intermediate leaves and visually homophyllous plants with capillary leaves from a single river basin, with the aim to evaluate their genetic polymorphism and taxonomic status-whether the plants with well-developed and weakly expressed intermediate leaves belong to different forms (taxa) or if they just express morphological variation of one or two taxa in a specific, very variable river environment. The studied heterophyllous and homophyllous plants from different rivers showed high genetic differentiation and a low level of genetic diversity within these groups. The molecular analysis did not reveal any inter simple sequence repeat (ISSR) polymorphism associated with the development of intermediate leaves. An analysis of nuclear ribosomal internal transcribed spacers ITS1-2 sequences revealed several ribotypes, which indicated the genetic heterogeneity of studied plants and indirectly confirmed the hybrid origin of some of them. Sterile plants originated from crossing of R. circinatus and R. penicillatus were discovered in the Skroblus River; however, identification of the parental species was impeded by the polymorphism detected. For this reason, cytological studies were performed and allowed confirmation of the hybrid origin of these plants

Bidens genties invazinių ir vietinių Lietuvos rūšių populiacijų genetinė įvairovė

River riparian ecosystems deteriorate because of anthropogenic factors that are related to industry, intensive agriculture and tourism. Two native species, Bidens tripartita and B. cernua, are weeds widespread in Lithuania on river banks and other habitats. An alien species, B. frondosa, is also widespread in the same habitats. We investigated the genetic diversity of B. frondosa, compared its population structure to that of related species and assessed the possibility of genetic interaction between B. frondosa and native congeners. Genetic analysis of populations was based on inter-simple sequence repeats (ISSR) polymorphism. Our results revealed high genetic differentiation in the B. frondosa populations (48.2%) and high genotypic diversity (i = 0.99). Bayesian cluster analysis using the program Structure revealed signs of gene flow between B. frondosa and the native species; however, principal coordinate analysis did not support this result. Our results do not indicate the role of interspecific hybridization in the invasiveness of B. frondosa. Įvairūs antropogeniniai veiksniai (intensyvi ūkinė veikla, turizmas, klimato kaita ir kt.) pažeidžia upių ekosistemas, sudarydami sąlygas plisti invaziniams augalams. Lietuvoje upių, ypač Nemuno, ir kitų vandens telkinių pakrantėse sparčiai plinta invazinis ilgakotis lakišius (Bidens frondosa L.). Ši rūšis sąveikauja su vietinėmis rūšimis ir dažniausiai jas išstumia. Upių pakrantėse ir kitose natūraliose bei antropogenizuotose augavietėse paplitusios dvi vietinės lakišiaus rūšys – triskiautis (B. tripartita) ir pelkinis (B cernua). Triskiautis lakišius yra žinomas ir kaip laukų bei daržų piktžolė. B. frondosa kai kuriose Europos šalyse irgi yra laikoma dirbamų laukų piktžole. Siekiant nustatyti, kokie genetiniai veiksniai gali būti palankūs plisti ilgakočiui lakišiui, tirta ir palyginta šių trijų rūšių populiacijų genetinė sandara bei įvairovė. DNR polimorfizmas buvo nustatytas paprastųjų pasikartojančių sekų intarpų (angl. inter-simple sequence repeats – ISSR) metodu. Tyrimo rezultatai parodė didelę B. frondosa populiacijų genetinę diferenciaciją ir genotipų įvairovę. Nors Bayeso klasterių analizė, atlikta programa Structure, rodė tam tikrus genų srauto tarp rūšių požymius, tačiau pagrindinių koordinačių analizė šio rezultato nepatvirtino. Tyrimo rezultatai parodė, kad tarprūšinė hibridizacija nėra B. frondosa invazyvumo priežastis. Šiai svetimkraštei rūšiai plisti palankus veiksnys gali būti didelė populiacijų genetinė ir genotipinė įvairovė

Extensive hybridization in Ranunculus section Batrachium (Ranunculaceae) in rivers of two postglacial landscapes of East Europe

We demonstrate a wide distribution and abundance of hybrids between the river species Ranunculus aquatilis, R. fluitans and R. kauffmannii with the still water species R. circinatus (Batrachium, Ranunculaceae) in rivers of two postglacial landscapes of East Europe, i.e., Lithuania and Central European Russia. The Batrachium species and hybrid diversity is higher in the rivers of Lithuania (4 species and 3 hybrids vs. 2 and 1) and represented mainly by western R. aquatilis, R. fluitans and their hybrids whereas in Central European Russia, the East European species R. kauffmannii and its hybrid are the only dominant forms. Hybrids make up about 3/4 of the studied individuals found in 3/4 of the studied river localities in Lithuania and 1/3 of the individuals found in 1/3 of the localities in Central European Russia. Such extensive hybridization in river Batrachium may have arisen due to the specificity of rivers as open-type ecosystems. It may have been intensified by the transformation of river ecosystems by human activities and the postglacial character of the studied landscapes combined with ongoing climate change. Almost all hybrids of R. aquatilis, R. fluitans and R. kauffmannii originated from unidirectional crossings in which R. circinatus acted as a pollen donor. Such crossings could be driven by higher frequency and abundance of R. circinatus populations as well as by some biological mechanisms. Two hybrids, R. circinatus × R. fluitans and R. circinatus × R. kauffmannii, were formally described as R. × redundans and R. × absconditus. We found a hybrid which most likely originated from additional crossing between R. aquatilis and R. circinatus × R. fluitans

Vandens augalų rūšių azoto koncentracijų sąsajos su žemės dangos tipu ir kitais aplinkos veiksniais

Baltijos šalių azoto (N) iškritų duomenys kartu su sausumos vandenų rodikliais rodo, kad azoto apkrova gali lemti augmenijos pokyčius. Nors upių eutrofikacija yra plačiai analizuojama, vis dar trūksta informacijos apie pakrantės augalų rūšių fiziologinius rodiklius. Tyrimo tikslas – palyginti Lietuvos vandens pakrančių augalų rūšių populiacijų lapų azoto koncentracijų duomenis, juos susiejant su tyrimo vietoms pagal gretimų žemių dangos tipu ir naudojimo paskirtimi, taikant aplinkos informacijos koordinuotos sistemą (CORINE), upių būkle bei dydžiu, žemės ūkio intensyvumu 1991–1996 metais ir upių vagų keitimu. Tyrimo medžiagą surinkus per 2015 m. rugpjūčio mėn. pirmąjį dešimtadienį iš pagrindinių Lietuvos upių 241 vietos, buvo įvertintos plačiai paplitusių penkių pakrančių ir dviejų vandens augalų (natūralių ir invazinių) azoto koncentracijos. Analizėms naudoti augalų lapai, kurių azoto koncentracijos buvo nustatytos Kjeldalio metodu. Didžiausi (1,7 karto, p < 0,05) lapų azoto koncentracijos skirtumai tarp populiacijų nustatyti Lythrum salicaria. Pagal populiacijų lapų azoto koncentracijų (N % sausos masės, SM) vidutines vertes, tirtų rūšių augalai išdėstė taip: Lythrum salicaria (3,0) < Stuckenia pectinata (3,1) < Phalaris arundinacea (3,5) < Bidens frondosa (3,8) < Phragmites australis (4,0) < Nuphar lutea (4,1) < Echinocystis lobata (4,2). Iš esmės didesnės (p < 0,05) lapų azoto koncentracijos buvo nustatytos Lythrum salicaria populiacijų, augančių šalia mažų upių (3,4 % N SM) nei augančių šalia didelių upių (2,8 % N SM). Skirtingomis savybėmis pasižyminčiose upių vietose rinkti vandens augalai reikšmingai nesiskyrė pagal lapų azoto koncentracijas. [...]Nitrogen (N) deposition data, together with inland water parameters, provide evidence that N load may affect the vegetation of Baltic States. There is much concern about eutrophication of the rivers, although information about physiological parameters of riparian plant species is still poor. The present study is aimed at comparison of leaf N concentration among populations of aquatic plant species of Lithuania, relating N concentration data to the type of land cover (classification system of COoRdinate Information on the Environment, CORINE) in the neighbouring areas, river state and size, intensity of agriculture in 1991–1996, and natural vice versa regulated fragments of the riverbed. The leaf N concentrations of widely spread native and invasive species (5 riparian and 2 water plants) were estimated for 241 sites (collection time 1st ten-day period of August, 2015) of the main river catchments of Lithuania. Only leaf blades were used for analyses and N concentrations were determined by the Kjeldahl method. The biggest (1.7 times) variation (p < 0.05) in leaf N concentration among populations was documented for Lythrum salicaria. According to the mean values (N % of dry mass, DM) of the leaf N concentration, species could be arranged into following order: Lythrum salicaria (3.0) < Stuckenia pectinata (3.1) < Phalaris arundinacea(3.5) < Bidens frondosa (3.8) < Phragmites australis (4.0) < Nuphar lutea (4.1) < Echinocystis lobata (4.2). Significantly higher (p < 0.05) concentrations of leaf N were found for L. salicaria populations growing near the small rivers (3.4% N DM) compared to the large ones (2.8% N DM). Other selected river and its environment parameters in most cases did not have significant effect on leaf N concentrations of aquatic plants of Lithuania. [...]Aplinkos tyrimų centrasBiologijos katedraGamtos mokslų fakultetasGamtos tyrimų centrasMatematikos ir statistikos katedraVilniaus Gedimino technikos universitetasVilniaus universitetasVytauto Didžiojo universiteta