Evgeniy A. Belyakov

The taxonomic composition and dynamics of vascular plant floras of the Nekrasovskaya floodplain lake (FL) located in the Yaroslavl–Kostroma lowland have been studied. The systematic structure of the lake flora has been established; it consists of 104 species from 2 divisions, 22 orders, 34 families, and 65 genera. Based on the annotated list of species, taxonomic, geographical, ecologocenotic, and ecobiomorphological analyses of the flora of the water bodies are studied. It has been found that the composition of the flora of water bodies, in general, corresponds to the ecologocenotic diversity of the water bodies in this territory. The differences in the flora of the experimental lakes are solely due to the diversity of biotopes, the transition with morphological features of the lake bed, and anthropogenic transformation. There have been no significant changes in the floral diversity of the lake systems in recent years.

Freshwater macrophytes shape not only the morphological “architecture” of shallow-water ecosystems but also their chemical milieu via low-molecular-weight organic compounds (LMWOCs) that may regulate phytoplankton, periphyton, and the microbiome within the leaf/shoot diffusive boundary layer and the surrounding water column. In this study, GC–MS (gas chromatography–mass spectrometry) was used to identify major LMWOCs of the low-molecular-weight metabolome (LMWM) in 11 widely distributed macrophyte species (Myriophyllum spicatum L., Sparganium emersum Rehm., Sparganium gramineum Georgi, the hybrid Sparganium × foliosum A. A. Bobrov, Volkova, Mochalova et Chemeris, Persicaria amphibia (L.) Delarbre, Potamogeton perfoliatus L., Nuphar lutea (L.) Sibth. & Sm., Potamogeton pectinatus L., Potamogeton natans L., Lobelia dortmanna L., and Ceratophyllum demersum L.). Compounds contributing more than 1% to the total LMWOCs pool were considered major, increasing the ecological realism of interpretations by focusing on metabolites more likely to reach effective concentrations in the plant microenvironment. For interspecific comparisons, the maximum recorded values of relative abundance and concentrations were used to estimate species “potential”. In total, 137 major LMWOCs were detected (four remained unidentified), and their numbers varied markedly among taxa (from 11 in N. lutea to 71 in P. perfoliatus). Similarity analyses (Jaccard, Sørensen–Czekanowski, Morisita–Horn) indicated that similarity based on compound lists and similarity based on dominance structure may diverge, reflecting differences between the “LMWOCs set” and the quantitative architecture of LMWOCs within the LMWM. Fatty acids formed the core of the major fraction in all species: they were among the top three compounds in all 11 macrophytes and ranked first or second in 10 of 11, highlighting the lipid module as a universal “structure–signaling–defense/allelopathy” hub in aquatic plants. Also, an analysis of the ecological-biochemical role of the main major LMWOCs in the studied aquatic macrophytes is presented. Overall, the data offer a comparable, ecologically oriented framework for interpreting chemical regulation of communities in macrophyte-dominated habitats and for selecting target compounds/species for subsequent bioassay and field studies.

Freshwater macrophytes shape not only the morphological “architecture” of shallow-water ecosystems but also their chemical milieu via low-molecular-weight organic compounds (LMWOCs) that may regulate phytoplankton, periphyton, and the microbiome within the leaf/shoot diffusive boundary layer and the surrounding water column. In this study, GC–MS (gas chromatography–mass spectrometry) was used to identify major LMWOCs of the low-molecular-weight metabolome (LMWM) in 11 widely distributed macrophyte species (Myriophyllum spicatum L., Sparganium emersum Rehm., Sparganium gramineum Georgi, the hybrid Sparganium × foliosum A. A. Bobrov, Volkova, Mochalova et Chemeris, Persicaria amphibia (L.) Delarbre, Potamogeton perfoliatus L., Nuphar lutea (L.) Sibth. & Sm., Potamogeton pectinatus L., Potamogeton natans L., Lobelia dortmanna L., and Ceratophyllum demersum L.). Compounds contributing more than 1% to the total LMWOCs pool were considered major, increasing the ecological realism of interpretations by focusing on metabolites more likely to reach effective concentrations in the plant microenvironment. For interspecific comparisons, the maximum recorded values of relative abundance and concentrations were used to estimate species “potential”. In total, 137 major LMWOCs were detected (four remained unidentified), and their numbers varied markedly among taxa (from 11 in Nuphar lutea to 71 in P. perfoliatus). Similarity analyses (Jaccard, Sørensen–Czekanowski, Morisita–Horn) indicated that similarity based on compound lists and similarity based on dominance structure may diverge, reflecting differences between the “LMWOCs set” and the quantitative architecture of LMWOCs within the LMWM. Fatty acids formed the core of the major fraction in all species: they were among the top three compounds in all 11 macrophytes and ranked first or second in 10 of 11, highlighting the lipid module as a universal “structure–signaling–defense/allelopathy” hub in aquatic plants. Also, an analysis of the ecological-biochemical role of the main major LMWOCs in the studied aquatic macrophytes is presented. Overall, the data offer a comparable, ecologically oriented framework for interpreting chemical regulation of communities in macrophyte-dominated habitats and for selecting target compounds/species for subsequent bioassay and field studies.

The biomorphological features of Scolochloa festucacea (Willd.) Link in the central part of European Russia have been studied; the modular and structural–functional organization of the shoot system has been considered and the life form has been clarified. It is found that S. festucacea is characterized by the innovation of a mixed type (a combination of intra- and extravaginal types) and a combination of silleptic and cataleptic types of branching. The presence of extravaginal renewal is manifested in the potential for the formation of partial bushes, the presence of which contributes to a stronger fixation of the plant in space. The combination of two types of branching leads to heterochrony, the development of buds at different times. The possibility of lodging of shoots, their further rooting in nodes, and the subsequent development of axillary buds into orthotropic shoots has been shown; this contributes to the correction of the spatial structure of the clone, the growth of its total assimilating surface, and a potential increase in reproductive function. A comparative analysis of the modular organization of S. festucacea has shown its similarity in the number and types of elementary modules with those of the long-rhizome sympodial growth of long-shoot helophytes. The analysis of the structural and functional organization of S. festucacea monocarpic shoots has revealed the presence of three variants differing in a set of structural and functional zones.

The new species records of rare and protected as well as few non-native species of vascular aquatic and semi-aquatic plants were found in the Republic of Adygeya and the Republic of Kalmykia, Krasnodar and Stavropol Territories, Astrakhan Region during 2014–2022. Typha elata are new floristic finding for the Krasnodar Territory, Typha tichomirovii for the Stavropol Territory, Najas major and N. minor for the Republic of Adygeya. Species regional conservation statuses have been evaluated and updated based on distribution and occurrence patterns. Data on new findings of rare (Berula erecta for the Republic of Kalmykia, Typha domingensis and T. shuttleworthii for the Krasnodar Territory) and protected species (Hydrocharis morsus-ranae, Salvinia natans, Najas major, N. minor, Potamogeton sarmaticus, and Typha laxmannii) in the North Caucasus and the southeast of the European part of Russia are presented. For the alien species Pontederia vaginalis and Najas graminea, a preliminary assessment of the risk of invasion has been carried out.

В ходе гидробиологических исследований четырех малых озер Ярославской области в 2013–2015 и в 2018 гг. в фитопланктоне было выявлено 92 таксона цианобактерий и водорослей, в зоопланктоне – 76 видов планктонных животных, в макрозообентосе – 26 низших определяемых таксонов. Оз. Рюмниково по показателям фитопланктона и зоопланктона имело наиболее низкий трофический статус (мезотрофный), в нем отмечено максимальное разнообразие и количественное развитие макрозообентоса. Озера Вашутинское, Чашницкое и Заозерье по показателям фитопланктона и зоопланктона оценены как эвтрофные, а разнообразие и количественное развитие макрозообентоса в них было на низком уровне, в том числе в связи с влиянием «цветения» воды и накопления сероводорода. In total, 92 taxa of cyanobacteria and phytoplankton algae, 76 zooplankton species, and 26 lower definable taxa of macrozoobenthos were registered during hydrobiological studies at four small lakes of the Yaroslavl Oblast in 2013–2015 and 2018. According to indicators of phytoplankton and zooplankton, Lake Ryumnikovo had the lowest trophic status (mesotrophic), but both the maximum diversity and abundance of macrozoobenthos. Lakes Vashutinskoe, Chashnitskoe and Zaozer'e were eutrophic, the macrozoobenthos diversity and abundance there were low, partly due to the water bloom effect and hydrogen sulfide accumulation.

Based on the study of three zones (free flow, estuarine and reservoir) transition sections tributaries of the plain reservoir, various aspects of the biology and ecology of three representatives of the genus Sparganium were examined. It was demonstrated that S. emersum, thanks to its high ecological plasticity, forms stands in all transitional zones of tributaries. Sparganium erectum participates in the formation of the vegetation cover in the estuarine and littoral zones of the reservoir, while S. microcarpum is not found in the littoral zone of the reservoir. It was shown that the latter two taxa are particularly sensitive to changes in the water level regime, which affects their ability to maintain their positions in phytocenoses. Using Sparganium as an example, it was established that the influence of the water level in the zone of river water discharge has an impact on the timing of reaching maximum biomass values, both in the free-flowing river zones and in their estuarine areas. It was found that the populations of S. emersum that achieve the greatest phytomass grow in the mouth areas of the reservoir tributaries, S. microcarpum, in the free flow zone of rivers, and S. erectum, in the mouth areas of rivers and in the littoral zone of the reservoir.

Geographical analysis has shown that Sparganium hyperboreum is most widespread in the forest-tundra and in the subarctic tundra subzone. In Western Siberia, this species grows in low and slightly mineralized and slightly acidic/neutral/slightly alkaline cool waters with fluctuating water level. It forms both monodominant communities (Sparganietum hyperborei purum association), and communities in which it is an edificator. In the southern tundra, S. hyperboreum is often found in anthropogenically transformed water bodies and man-made reservoirs. The species is characterized by high vegetative mobility and ecological plasticity with four ecological forms, depending on the depth of growth. Along with this, S. hyperboreum is characterized by only one life form.