Influence of abiotic factors on incubation of Baikal omul eggs in the Selenga River (Lake Baikal Basin)

Abiotic factors affecting the choice of spawning sites for the Baikal omul (Coregonus migratorius) in the Selenga River over 27 years were studied. A total of 3,450 samples were collected using the Dulkeit scraper in Decembers of 1987-2014, at 24 trans-sections in the Selenga River channel over a total length of 410 km. At each sampling site we recorded omul egg density, substrate particle size, water depth, water flow velocity, and ice thickness. Omul eggs were found mainly on hard substrates (sand, gravel, pebbles, and pebble-cobbles combinations). Omul has been found to avoid spawning at depths less than 1.5 m and greater than 6.0 m. Water velocity and ice thickness did not strongly influence the choice of site. Omul eggs were found at flow rates of 0.05-0.7 m/s with a maximum at 0.1 m/s.

Leukocyte composition of pronephros of Leocottus kesslerii infected with hemoflagellates of the genus Trypanosoma (Kinetoplastea: Trypanosomatida)

This study determined for the first time the changes in leukocyte composition of the pronephros (head kidney) of sand sculpin Leocottus kesslerii, (Sideleva, 2001) (Lake Gusinoye, Lake Baikal basin, Eastern Siberia, Russia), infected and uninfected with hemoflaggellates of the genus Trypanosoma. The results indicated that the trypanosomes modulated the development of the immune response of their host (suppression of B cell immunity and granulocytic reactions, activation of the leucopoiesis and monocytopoiesis). Selective suppression of immune response in host with trypanosomes promotes the survival and development of parasites.

First Findings of Sunbleak Leucaspius delineatus (Cyprinidae) in the Lake Baikal Basin

Since the early 1960s, the sunbleak Leucaspius delineatus (Heckel, 1843), along with carp acclimatized from European Russia, regularly entered the siberian carp ponds, first in the Ob’ basin, and then in the Yenisei and Angara basins. In the last decade, we have discovered the sunbleak in two water bodies of the Baikal basin: in May 2013 - in the water intake and discharge canals of the Gusinoozersk regional power plant situated on the large lake Gusinoe in the Selenga River basin (Republic of Buryatia), and in November 2016, the sunbleak was registered in the diet of pike inhabiting the reservoirs of the Talaya-Pokhabikha lake-bog complex in the immediate vicinity of the Baikal coastline at the southern end of the lake in Irkutsk Region. The age series in the samples of the sunbleak in the water intake canal of the power plant was represented by five age groups from 1+ (SL 34.2 mm and 0.59 g of weight) to 5+ (SL 73.9 mm and 6.73 g, respectively) with a predominance of individuals aged 1+ and 2+. In the discharge canal only group 1+ (SL 35.5 mm and 0.69 g) was noted. The sex ratio in catches at the age of 1+ was 1:1.2 with a predominance of males; by the age of 3+, the proportion of males increased significantly (1:8.6). Sexual maturity of the sunbleak from Lake Gusinoe occurs at the age of 3+. Spawning is portioned, the first portion is layed down not earlier than the second half of July. The total fecundity of the seven studied females at the age of 3–5 + varies from 632 to 1539 eggs, averaging 1312 eggs. The sunbleaks from Lake Gusinoe are predominantly benthophagous. In the first half of May 2013, near the water intake canal, the main food components were the nymphs of the Corixidae water bugs and larvae of Phryganea caddis flies, planktonic crustaceans and imago of aerial insects were also consumed. In July 2014, in the discharge channel, the main food item was the chironomid larvae. In the lake Sludyanskoye, three specimens were identified from the stomachs of the pike living there. All fish were partially digested, and therefore it was not possible to analyse it.

Landscape-Cartographic Analysis of Changes in the Taxonomic Diversity of Soils Zoocenoses in Baikal Region

The paper presents a landscape-ecological analysis of the mesopopulation structure of the geosystems in the Baikal region. The regularities of changes in the quantitative characteristics and taxonomic diversity of invertebrate communities in the landscape-ecological range under the influence of natural and anthropogenic factors at different levels of the organization of geographical space are considered. The data were obtained as a result of a detailed study of the quantitative characteristics of invertebrate communities in the key polygons of the taiga, mountain-taiga and steppe geosystems of the Lake Baikal basin. Numerous cartographic materials, information about the soil cover and the state of vegetation are analyzed, data on the heat supply and moisture supply of soils are taken into account. The main trend of changing the diversity of pedobiont communities is a decrease of species number in the gradient of increasing aridity of the climate, increasing hypothermia and anthropogenic pressure. Based on the data obtained, the map “Taxonomic diversity of soil-biotic communities in the geosystems of the Lake Baikal basin” is presented. Conservation of biological diversity is considered as one of the most important conditions for sustainable development and rational use of natural resources.

Effects of Climatic Warming and Wildfires on Recent Vegetation Changes in the Lake Baikal Basin

The vegetation changes in the area of the Russian part of the Lake Baikal water basin for the period 2010–2018 were investigated using MCD12C1 land cover. The decline in swamp systems area began in 2012 and continued until 2015, after which it partially recovered during the heavy rain season in 2018. During the period of 2010–2018, the area covered by forests did not exceed 20.3% of the Baikal basin of the total portion of the Baikal basin under study. Deforestation began in 2013 and continued until 2017. Over 2013–2018, the forest level decreased by 12.1% compared to the forest state in 2013. The analysis of summer rainfalls and aridity indexes was performed by using CRU TS and GPCC climatic datasets. It is shown that the interannual variations of precipitation and aridity changes are determined by the variability of the global circulation of moist air masses. The MCD64A1 (burned area) and MCD14ML (active fires) MODIS products were used for investigation of the influence of wildfires on vegetation changes. The spatial hotspot distributions and burned areas in general correspond to aridity zones, but they cannot explain the 20-fold increase in the number of wildfires. Most of the hotspot locations are away from settlements, roads, and loggings, in difficult-to-access mountainous areas, as well as in the low-inhabited areas of Siberia. We assume that the nature of such ignitions includes dry thunderstorms, pyrocumulus lightning, or remote impact.