Архив метки: steppe fires

LONG-TERM DYNAMICS OF STOCKS OF LIVING ABOVE-GROUND PHYTOMASS OF STEPPE PHYTOCENOSES AFTER A WILD FIRE (ON THE EXAMPLE OF THE BURTINSKAYA STEPPE OF THE ORENBURG NATURE RESERVE)

Arid Ecosystems

UDC 581.5;58.02

Dusaeva G.Kh., Kalmykova O.G. LONG-TERM DYNAMICS OF STOCKS OF LIVING ABOVE-GROUND PHYTOMASS OF STEPPE PHYTOCENOSES AFTER A WILD FIRE (ON THE EXAMPLE OF THE BURTINSKAYA STEPPE OF THE ORENBURG NATURE RESERVE) // Arid Ecosystems. 2023. Vol. 29. № 2 (95). P. 67-76. | PDF

In recent years the area and frequency of wild fires was growing catastrophically in the steppes of the arid regions of the Russian Federation. The fires destroy the above-ground part of phytocenoses, significantly reducing the stocks of above-ground phytomass and productivity of communities, and changing the structure and composition of steppe phytocenoses. The purpose of our work was to study the effect of the pyrogenic factor on the stocks of living above-ground phytomass, and determine the time required for its full recovery. After a wild fire in 2015, 6 monitoring sites were established in the Burtinskaya Steppe of the Orenburg Nature Reserve. Each site included a control (intact) plot and a burned plot. Standard geobotanical methods were used along with mowing to identify the features and dynamics of the stocks of living above-ground phytomass. The studies were carried out in 2015-2020. As a result, we found out that the reserves of phytomass (g/m2) can reach the value of the control communities in the 2nd year of the study. The seasonal dynamics of live phytomass starting from the 3rd to 4th year after burning are mostly affected by the community composition and type instead of the pyrogenic factor. During the entire period of our study, the proportion of live phytomass stocks of burned communities reached the values of control phytocenoses. However, it was always higher than the control values, which indicates incomplete restoration of the structure of the above-ground phytomass of the burnt area.

Keywords: steppe fires, stocks of living above-ground phytomass, seasonal dynamics, year-to-year dynamics, protected areas, revegetation, Orenburg region.

Financing. The work was carried out for the state task of the Steppe Institute of the Ural Branch of the Russian Academy of Sciences “Problems of Steppe Nature Management in the Conditions of Modern Challenges: Optimization of the Interaction of Natural and Socio-economic Systems” (Project No. GR AAAA-A21-121011190016-1).

DOI: 10.24412/1993-3916-2023-2-67-76

EDN: HKXEXJ

FEATURES OF FORAGE VEGETATION AS ONE OF THE POSSIBLE CAUSES OF MASS DEATH OF SAIGA ANTELOPE ON STEPPE PASTURES

Arid Ecosystems

Abaturov B.D.,  Gorbunov S.S.,  Koshkina A.I. FEATURES OF FORAGE VEGETATION AS ONE OF THE POSSIBLE CAUSES OF MASS DEATH OF SAIGA ANTELOPE ON STEPPE PASTURES // Arid ecosystems. 2021. V.27. № 4 (88). P. 93-100. | PDF

Modern climatic changes, weakening of the anthropogenic pasture load, the growth of steppe fires, have caused the expansion and dominance of grasses vegetation on the steppe pastures of Russia and Kazakhstan since the end of the 20th century, which caused a deterioration in the forage quality of pasture vegetation, was one of the reasons for the depression of the saiga population and, of the increase in cases of mass mortality of saigas. Mass deaths of saigas occurred in Kazakhstan in 2015, when about 200,000 animals died. A large number of different versions have been put forward about the causes of death: from an infectious disease (hemorrhagic septicemia), toxic forage plants, unfavorable weather conditions, to the destructive effect of rocket fuel. In this article, we have considered a different versions of death associated with the negative effect of low-quality food in places of death of saigas. It has been shown that the supply of food to saigas on steppe pastures consistently decreases with an increase in the abundance of grasses in forage vegetation. Suitable pastures that provide adequate nutrition for breeding saigas include pastures with a share of grasses in the aboveground phytomass of no more than 30%. If this level is exceeded, the pastures do not provide the necessary level of nutrition for the breeding saigas and are unsuitable for them. It is possible that during the spring migration the saigas found themselves within the steppe regions with a predominance of turf grasses (65-75%), exceeding their permissible (threshold) abundance (30%). This condition of the pasture did not provide the necessary nutrition, caused a weakening of animals during the rearing period, promoted the activation of infectious septicemia in breeding saigas, which, possibly, with the combined action of both factors, led to their mass death.

Keywords: Saiga antelope, steppes of Kazakhstan, steppe fires, abundance of grasses, suitability of pastures, mass mortality of saigas, pasteurellosis, hemorrhagic septicemia, forage quality of vegetation, forage digestibility, forage availability.

Financing. The work was carried out under a grant of Russian Foundation for Basic Research, project No. 18-04-00172: «Toxic components in the vegetation of natural pastures as indicators of the quality of forage resources, their impact on food security and the state of populations of herbivorous mammals in terrestrial ecosystems.»

DOI: 10.24412/1993-3916-2021-4-93-100