M. L. Sizemskaya’s research while affiliated with Russian Academy of Sciences and other places

The study investigated ash development in an arid region, focusing on its invasive spread mechanisms at organismic and ecosystem levels under varying moisture conditions. Conducted in the Northern Caspian region’s Volga-Urals interfluve, it examined the effects of arid climate, soil salinity, and limited moisture on plant communities. The features of ash functioning at the organismal and ecosystem levels with permanent and partial deficiency of productive moisture in the soil, as well as with its optimal availability, were investigated. It is shown that on automorphic soil types, ash cultures, subject to appropriate forestry technologies, can exist for many decades even during periodic soil droughts due to premature harmless dumping of leaf mass. In hydromorphic floodplain conditions, ash is not only well preserved in cultures, but also effectively introduced into meadow and forest ecosystems by lowering the relief. Trees in a new place, especially in meadows, begin to bear fruit after 6-10 years and spread the seeds to other territories. Such a nomadic strategy of stepwise dispersed multiple dispersal of ash contributes to the rapid formation of its secondary invasive areas and eliminates the possibility of effective control against it. Therefore, the use of ash in industrial plantings in floodplains is highly inadvisible.

Представлены результаты изучения видового разнообразия и состояния интродуцентов в богарных условиях на территории Джаныбекского стационара Института лесоведения РАН, расположенного в глинистой полупустыне Северного Прикаспия междуречья Волги и Урала. Были обследованы коллекции двух дендрариев: на гидроморфных лугово-каштановых почвах мезопонижений рельефа – на падине (заложен в 1953 г.) и на автоморфных почвах солонцового комплекса (заложен в 1974 г.). Они создавались принципиально без полива, а агротехнические и лесоводственные уходы были вынужденно прекращены в силу ряда причин в последние десятилетия. Составлен аннотированный список древесных и кустарниковых растений, включающий на современном этапе 77 видов, относящихся к 25 семействам и 44 родам. Большинство представлено семейством Rosaceae, весьма многочисленны виды семейств Caprifoliaceae, Elaeagnaceae, Fagaceae, Fabacea, Oleaceae, Salicaceae, Sapindaceae, Ulmaceae. Часть экземпляров в возрасте более 70 лет имеет удовлетворительное состояние и полноценный жизнеспособный самосев. Выделены основные периоды акклиматизации, связанные с возрастом, особенностями изменения условий местопроизрастания под воздействием самих растений и климата. В дендрарии на почвах солонцового комплекса сохранность видов составила 50%. Также изучен состав деревьев и кустарников, спонтанно заселивших неиспользуемый пруд и сформировавших здесь интразональное ивово-лохово-тополевое сообщество квазитугайного облика, и на зарастающей залежи, где образовался своеобразный “саванноподобный” ландшафт. Это позволило выявить виды, жизненная стратегия которых способствует успешному внедрению в антропогеннонарушенные условия местопроизрастания и, в ряде случаев, проявлению черт натурализации и инвазионность. Определены также наиболее перспективные виды для озеленения, создания парков, ягодников и других насаждений в столь суровых природно-климатических условиях.

The species diversity and safety of a 70-year-old collection of tree and shrub introduced species in the arboretum of the Dzhanybek Research Station, located in rainfed conditions of the semi-desert of the Northern Caspian region, was studied. The arboretum was created on hydromorphic meadow-chestnut soils in a mesodepression of relief in 1953. At the present stage, 75 species belonging to 23 families and 43 genera have been identified in the arboretum. It was analyzed that most of the species are represented by the family Rosaceae, the species of the families Caprifoliaceae, Elaeagnaceae, Fagaceae, Leguminosae, Oleaceae, Salicaceae, Sapindaceae, Ulmaceae are very numerous. Species with high ecological and biological potential have been identified. It is concluded that due to their own longevity, adaptive reactions, good self-renewal abilities, many species can exist for a long time and stably in semi-desert conditions. Species that can be recommended for creating sustainable socially significant plantations are proposed.

The soil cover of semi-desert territories is sensitive to modern climatic changes, responding to a change in the composition of soil complexes. Soil microstructure features reflect minor changes in microrelief or fluctuations in the level of groundwater. This property of soil microstructure to memorize soil formation conditions is used for subsequent characterization of changes in long-term climatic trends. But in semi-desert climates, it can be used as an indicator of short-term weather series. This article presents data collected on the territory of the Caspian Depression in the Dzhanybek Research Station of the Institute of Forest Science RAS. The soil cover of the studied site of this station is represented by a semi-desert, two-component meadow-steppe Solonetzic soil complex that strictly follows the elements of the local micro(micro)topography. The height range between the studied pits is 8 cm. The dataset includes micromorphological photographs of the state of the soil complex in 2005. This year is an initial moment for modeling soil properties at the present day taking into account the changed weather parameters. The weather data was collected between February 2005 and June 2021. It includes daily, decadal and monthly data related to air temperature, relative air humidity, wind speed and precipitation, soil temperature and depth of freezing (thawing) of the soil, snow cover depth. The measurement methods did not change throughout the entire observation period, which makes it possible to use the data to correct forecasts of the response of drylands to modern climatic changes with the subsequent verification of models in the field at present.

Features, trends and the rates of formation of new forest biogeocenoses on anthropogenically disturbed lands, in particular, on an unused pond created on heavy loamy soils in the semi-desert of the Northern Caspian region are analyzed. At an early stage of spontaneous pond colonization by vegetation, the maximum influence on its development was exerted by the presence of a seed source 300 meters away – in the Arboretum of the Dzhanybek Research Station of the Institute of Forest Sciences (Russian Academy of Sciences) with 120 species of introduced tree and shrub plants. Initially 34 pioneer species colonized the lower parts of the unused pond, and 29 species survived by 2018. The formation of intrazonal willow-oleaster-poplar communities of a quasitugai type with a grass-wet-meadow association has been revealed. Their development was influenced by geographical isolation, self-regulation under rather unstable moisture conditions caused by occasional flooding by melt snow waters and bogging. A differentiation of the upper part of the soil-forming rock brought to the surface has occurred. The forest leaf litter has been formed from uncut moquette with a thickness of 1–2 cm, reaching currently quite substantial deposits of 0.953±0.196 kg/m2 , with the ash content reaching 13.85%. Ca prevails absolutely in the ash composition; while the amounts of Mg, Fe, and K are significantly lower. A humus horizon has been formed and the soil effervescence depth has changed. In the whole, for almost 40 years of vegetation colonization, the previously infertile substrate has acquired features of an immature soil, which is characterized by manifesttion of humus-accumulative process, gradual humification of organic matter and decarbonization of the material. In general, compact, diverse in structure, spontaneously arising self-developing forest biogeocenoses could significantly transform disturbed semi-desert territories. The peculiarities of their structure and the composition of emerging species make it possible to properly choose species preferred for landscaping.

The results of an ongoing 50-year experiment of introduction of the species Eisenia nordenskioldi into massive oak plantations (Quercus robur L.) in the Northern Caspian semidesert are analyzed. The change in the quantitative proportion of the dominant earthworm species due to the growth and conditions of forest cultures as well as their impact on meadow-chestnut soils is considered.

A wavy trend toward increasing vegetation biomass in desert, semidesert, and steppe communities growing on solonetzic soils was discovered in the Northern Caspian region over a 60-year observation period (1952–2013). The trend is caused by warming during winter months (due to redistribution of soil moisture) and the improvement of hydrothermal conditions in spring months (the period of most active plant vegetation).