A new species of the genus Nupela, N. mongolica sp. nov., is described from Davaa Lake, Mongolia. The new species has been studied in LM, SEM and TEM, illustrating the unique structure of the areolae that is characteristic for this genus. According to the molecular analysis, N. mongolica sp. nov. forms an independent branch within the clade that includes other species of Nupela. The genus Nupela was originally placed in the suborder Neidiineae with an unclear position within the suborder due to its unique morphology; later it was included in the family Brachysiraceae despite the differences between Nupela and Brachysira. Molecular data show that strains of Nupela form a separate clade that is not closely related to other genera. Based on the distinct morphological structure of areolae in Nupela that is not present in any other pennate diatoms and the separate position of Nupela species on the phylogenetic tree, a new family Nupelaceae fam. nov. is suggested to accommodate this genus.

The greenery of floodplain meadows in arid regions, such as Mongolia, is influenced by climate, hydrology, and land use. In this study, we analyzed the NDVI (Normalized Difference Vegetation Index) of two floodplain meadows located along the South Tamir and Tamir Rivers using LANDSAT images. Our goal was to observe NDVI spatial changes, variations, and mean values in mid-August every six years from 1991 to 2015 and to identify the factors driving these differences. To achieve this, we conducted variance analysis to identify changes in NDVI and implemented Principal Component Analysis to determine the influence of hydro-meteorological factors and grazing intensity. Our findings indicate a significant decrease in greenness, as measured by pixel-scale NDVI, during the late summer period. This decrease was consistently observed, except for a series of harsh winters that followed relatively dry summers, resulting in a disastrous event called dzud, which led to the death of livestock. The decrease in NDVI was amplified by lower precipitation in June, higher temperatures and wind speed in July, and increased precipitation in August, along with a higher frequency of days with convective rain. Our findings have important implications for managing grazing in Mongolia’s grasslands, promoting sustainable land use, and mitigating sandstorms. The variance and average values of NDVI at the pixel level can serve as reliable markers of sustainable pasture management in areas where other vegetation measures are limited.

An unknown species of the diatom genus Paraplaconeis was discovered during a field study of freshwater environments in Central Mongolia. In the course of further study, two monoclonal strains were acquired for the unknown species. The strains were utilized for molecular-genetic analysis on SSU rRNA and rbcL genes. As a result of the molecular investigation and careful morphological examination of valve structure with light and scanning electron microscopy, we propose the description of a new species—Paraplaconeis dorofeyukae sp. nov.—in this article. The new species is morphologically compared to similar taxa from the Paraplaconeis placentula group. Paraplaconeis dorofeyukae sp. nov. can be distinguished from related species by a combination of valve dimensions, morphology of apices and central area, and external valve ultrastructure.

Six strains of Platessa conspicua isolated from Lake Khövsgöl, Mongolia, have been studied with the use of light and scanning electron microscopy and molecular methods. The phylogenetic analysis shows the inclusion of P. conspicua into the family Achnanthidiaceae and its close relationship with the genera Lemnicola and Gogorevia. The phylogenetic position of the species and its morphological characteristics are discussed and an epitype strain is designated. This study is the first molecular study of representatives of Platessa and one of the first polyphasic investigations of monoraphid diatoms in Mongolia.