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Distribution omul map

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Hydroacoustic measurement of the Baikal omul resources

In 2011, the assessment of the number and biomass of the Baikal omul Coregonus migratorius was carried out using the hydroacoustic method [1].

The results of the assessment are shown in Tables 1 and 2. The distribution of the number and biomass of the Baikal omul in the water area of Lake Baikal is uneven. Amassments with the density above average take less than a quarter of the examined area. However, they contain almost two thirds of the Baikal omul reserves. A general picture of the spatial distribution of the omul in the lake's water area corresponds with trawling and acoustic measurements. Our work confirmed the necessity of conducting such measurements immediately after ice clearance, but before the start of feeding migrations of the Baikal omul. During this period, the omul forms dense shoals that are easy to register using the hydroacoustic technique, which improves the accuracy of measurements. The derived number and biomass figures of the Baikal omul, especially in the Selenga shallow water area and Northern Baikal, correspond quite well with the forecast of the long-term dynamics based on the peculiarities of the size- and age-related composition of the fish population[2].

We confirmed the findings about the presence of a significant part of the omul population in the deep-water zones of the lake.

References:

Makarov, M. M., Degtev, A. I., Kucher, K. M., Mamontov, A. M., Nebesnykh, I. A., Khanaev, I. V. & Dzyuba, E. B. (2012). Assessment of the number and the biomass of the Baikal omul using trawling and acoustic techniques. DAN, 447(3). p 343-346.

Melnik, N. G., Smirnova-Zalumi, N. S., Smirnov, V. V., et al. (2009). Hydroacoustic measurement of the Baikal omul resources. Novosibirsk: Nauka. p 244.

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Disturbance of forest lands map

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Disturbance of forest land

Under the disturbed land we understand the value that reflects the ratio of the reforestation fund area to the area of forest lands (on the forest fund lands and other land categories, where forests are located). Reforestation Fund consolidates the areas of forest land with stands, damaged by fires, pests and logging. Forest land in contrast to non-forest one represents a category with the following main functions: cultivation, conservation, improving the properties of the main forest forming species. The major part of the forest land is forested and the rest is not covered by forest (burnt areas, dead stands, slashes, clearing sand wastelands). There the reforestation measures are conducted, thus, they contribute to natural regeneration.

On the territory of the Russian part of the Baikal basin, the average disturbance of forest land is 6.1%. It is fluctuating from 0.06 % in the Krasnochikoysky district of Zabaikalsky krai to 9% in the Kizhinginsky district of the Republic of Buryatia. In the Mongolian part of the basin, the disturbance of forest land is higher than in Russia – on the average 9.7%. However, in aimags it is fluctuating from 0.1 to 19.9 %. In six aimags the disturbance of forest lands is more considerable – more than 10%. Such a situation in Mongolia is possibly caused by more accurate description of forest areas with damaged forest stands.

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Disturbance of wildlife map

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Disturbance of fauna

The growth of industry and agriculture, increase of population and its demands from the second half of the 20th century have interfered with the Lake Baikal ecosystems, leaving very few places untouched by people’s activities. Anthropogenic impact on the wild animals of the Baikal basin was also quite considerable. Indigenous animals and intact habitats are preserved only on the restricted territories, where human activities are limited by special factors (reserve status, hard access, harsh natural conditions, etc.)

The disturbance of wild animals is regarded as any change of the existing populations and communities manifested in the decrease in size, loss, and fragmentation of habitats, variations in species composition, including introduction of new species, and changes in the ecosystems. As a result, the indigenous species or communities can no longer exist [Belov et al., 2002] The disturbance of zoocenosis directly correlates with the intensity of human activities. As a rule, the mostly disturbed fauna complexes are located in the basins of major rivers, where people settled long time ago. The composition of species in these areas is represented by flexible eurytopic species, as well as synanthropic and invasive animals. Quite often the species not common for the biocenosis of some ecosystems start to dominate, when the ecosystem has been disturbed.

Plowing, cattle grazing, forest cuts, fires, construction works, mining, and solid and gaseous pollutant emissions influence the vertebrates fauna directly or indirectly causing changes of ecosystems, reduction in the size of animal populations, and fragmentation or full transformation of communities. Agriculture is the major factor that determines the fauna of the most part of the basin. Overgrazing and plowing deteriorate habitats, transform structure and species composition of vertebrates, and destroy nests of ground-nestling birds. Fauna complexes of the steppe zone suffer most from the abovementioned two factors. In highly degraded steppes, vertebrates are extinct almost totally. Logging and steppe and forest fires greatly affect the habitats of vertebrate animals, its species’ composition, structure, and abundance of certain species. A complex multilayered ecosystem is replaced by open spaces with altered protective, feeding, and microclimatic conditions that bring about significant changes of vertebrates. Post-fire changes in ecosystems are so drastic that restoration of certain species of vertebrates does not happen for decades.

Invasive alien species are justly regarded as one of the two most hazardous threats to biodiversity, coming second only to the devastation of habitats. In the XX century, intentional and unintentional introduction of various animals as a result of intensive economic activities became a global problem of the biotic exchange between biogeographical regions [Tishkov et al., 1995]. The significance of this problem has not been fully recognized yet. In the Baikal basin, the zones where fauna suffers from the introduction of alien species, are localized in the areas of long-term anthropogenic activities; however, there is a clear trend towards areal expansion of the adventive species of fauna. Introduction of alien species has an adverse impact on biodiversity and the structure and functioning of ecosystems. Synanthropes invade settlements, warehouses, industrial buildings, causing economic loss.

Diversity of fauna and the abundance of animals made hunting very attractive in the Baikal basin. As a result of long-term and intensive harvesting of birds and animals, their populations were put at risk of extinction; many of these species were listed in the regional Red Books. At present, hunting is not so popular, which has an ambiguous effect on the animal populations. Some species (Far Eastern red deer, wolf, squirrel, muskrat, Siberian striped weasel, and ermine) grow in number due to the reduced harvesting pressure and the extension of the areas disturbed by anthropogenic factor (deforested and post-fire lands). Populations of other species (roe deer, Siberian musk deer, and sable) are shrinking in size due to poaching. Hoofed mammals in Mongolia are on the margin of their habitats; therefore, their populations are rather small and require special protection and size regulation. Populations of other species are stable in size over the years, and the fluctuations are determined by natural dynamics.

Pollution and drainage of water bodies, changes in their hydrological regime due to damming, increase of water intake, disposal of wastewater by dilution, and unlimited fishing had a negative effect on the populations of many fish species, especially valuable commercial species. The rise of the Baikal water level by one meter after the construction of the Irkutsk hydro power plant reduced spawning areas of some fish species, changed nutritive base and feeding places that caused weight loss of some fish species [Monitoring …, 1991; Hydropower …, 1999] Some nestling grounds of semi-aquatic birds in the river estuaries were flooded. There is also evidence that some species of fish and freshwater seal (nerpa) accumulate heavy metals, radioactive isotopes, and chlororganic compounds [Grachev, 2002].

The map “Disturbance of fauna” gives an idea about the present state of the communities of the vertebrate animals in the Baikal basin. The map was created with the use of methodological guidelines for making evaluation maps developed by scientists at the V.B. Sochava Institute of Geography SB RAS [Belov et al., 2002]. The key information about the changes of the regional fauna complexes was obtained from the cartographic materials, Landsat space images, statistics on forest fires, forest cuts, and industrial pollution, and from other published materials [Atlas of the Trans-Baikal region, 1967; National atlas: Mongolian People’s Republic, 1990; Atlas of ecosystems of Mongolia, 2005]. The map was developed on the basis of vegetation maps and flora disturbance maps published in the abovementioned atlases. The map’s explanatory note distinguishes three stages of disturbance of the indigenous ecological fauna complexes and ichthyofauna. Additionally, we provide information about extinct and near-extinct vertebrate animals and primary causes of the fauna complexes’ disturbance and degradation. This map can serve as a resource for developing recommendations on the protection and rational use of the Baikal basin’s wildlife.

 

References

Atlas of the Trans-Baikal region. (1967). Moscow-Irkutsk. p 176.

Belov, A. V., Lyamkin, V. F., & Sokolova, L. P. (2002). The cartographic study of the biota. Irkutsk: Oblmashinform. p 160.

Atutov, A. A., Pronin, N. M., & Tulokhonov, A. K. (1999). Hydropower industry and the ecosystem conditions of Lake Baikal. Novosibirsk: SB RAS Publishing. p 281.

Grachev, M. A. (2002). On the current state of the Baikal ecosystem. Novosibirsk: SB RAS Publishing. p 156.

National atlas: Mongolian People’s Republic. (1990). Moscow-Ulaanbaatar. p 144.

Israel, Y. A., Anokhin, Y. A. (1991). Monitoring of the state of Lake Baikal. Leningrad: Hydrometeoizdat. p 262.

Tishkov, A. A., Maslyakov, V. Y., & Tsarevskaya, N. G. (1995). Anthropogenic transformation of biodiversity in the process of unintentional introduction of organisms (biogeographical consequences). Bulletin of the Russian Academy of Sciences: Geography, 4. p 74-85.

Atlas of ecosystems of Mongolia. (2005). Moscow. p 48.

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