Using the statistical data on fires in Russia, the study concludes that it is necessary to assess fire risks for preschool and educational institutions. The factors influencing the occurrence of ...fires are considered. Tools and resources for predicting fire risks are described. The methodology of assessing fire risks for preschool and educational institutions is analyzed. A fire risk for the facility under study is caluclated. The calculation is based on the method of constructing “bounce” trees, successfully used in the graph theory. The key event is a fire, the risk of which is etermined. The logic elements “and”, “or” and “inverter” are used in the construction. The block diagram has several levels - from the key to the simplest failures. The advantage of this scheme is described. In addition to the main fire risk for the facility, the professional risk is caluclated. Taking into account the result, measures aimed to ensure fire safety at these facilities are suggested. The article concludes that it is necessary to use the fire risk assessment method.
This paper presents a reconstruction of natural environmental dynamics, wildfires and vegetation change in northwest Putorana Plateau during the last 1300 years. The study area is a remote and poorly ...investigated region of subarctic Siberia, relatively untouched by human impacts, which offers a unique opportunity to examine natural environmental dynamics and climate-vegetation-fire relationships. The paleoenvironmental reconstructions are based on multi-proxy analysis of the Gervi peatland including pollen, plant macrofossil, testate amoebae and charcoal analysis, loss on ignition measurements and AMS radiocarbon dating. The results revealed the main phases of regional paleoenvironmental change: a warm period between 680 and 1200 C.E. (Common Era) corresponding to the Mediaeval Climate Anomaly (MCA), followed by climate cooling during the Little Ice Age (LIA, 1200–1850 C.E.) and subsequent centuries. Climate amelioration during the MCA led to afforestation of northwestern Putorana Plateau and an expansion of spruce extending 70 km northeast of its present geographical range. A quantitative water-table reconstruction was generated using a testate amoebae transfer function and suggested that relatively dry climate conditions during the MCA triggered high fire frequencies. The LIA appeared in the study area as a period of pronounced climate cooling and moderate moistening, which caused an extension of tundra vegetation and a dramatic decline of fire activity. Distinct environmental changes at the study site were detected since 1990 C.E., characterized by a high peat accumulation rate and rising water table. Since 1990 C.E., the macroscopic charcoal accumulation rate in the peat core increased abruptly, suggesting a recent increase in the fire frequency in the study region.
Recent findings indicate that Nod factor signalling is tightly interconnected with phytohormonal regulation that affects the development of nodules. Since the mechanisms of this interaction are still ...far from understood, here the distribution of cytokinin and auxin in pea (Pisum sativum) nodules was investigated. In addition, the effect of certain mutations blocking rhizobial infection and subsequent plant cell and bacteroid differentiation on cytokinin distribution in nodules was analysed.
Patterns of cytokinin and auxin in pea nodules were profiled using both responsive genetic constructs and antibodies.
In wild-type nodules, cytokinins were found in the meristem, infection zone and apical part of the nitrogen fixation zone, whereas auxin localization was restricted to the meristem and peripheral tissues. We found significantly altered cytokinin distribution in sym33 and sym40 pea mutants defective in IPD3/CYCLOPS and EFD transcription factors, respectively. In the sym33 mutants impaired in bacterial accommodation and subsequent nodule differentiation, cytokinin localization was mostly limited to the meristem. In addition, we found significantly decreased expression of LOG1 and A-type RR11 as well as KNOX3 and NIN genes in the sym33 mutants, which correlated with low cellular cytokinin levels. In the sym40 mutant, cytokinins were detected in the nodule infection zone but, in contrast to the wild type, they were absent in infection droplets.
In conclusion, our findings suggest that enhanced cytokinin accumulation during the late stages of symbiosis development may be associated with bacterial penetration into the plant cells and subsequent plant cell and bacteroid differentiation.
The response of peatlands to climate change can be highly variable. Through understanding past changes we can better predict the response of peatlands to future climate change. We use a multi-proxy ...approach to reconstruct the surface wetness and carbon accumulation of the Mukhrino mire (Western Siberia), describing the development of the mire since peat formation in the early Holocene, around 9360 cal. year BP. The mire started as a rich fen which initiated after paludification of a spruce forest (probably in response to a wetter climate), while the Mukhrino mire progressed to ombrotrophic bog conditions (8760 cal. year BP). This transition coincided with the intensive development of mires in Western Siberia and was associated with active carbon accumulation (31 g m
−2
year
−1
). The ecosystem underwent a change to a tree-covered state around 5860 cal. year BP, likely in response to warming and possible droughts and this accompanied low carbon accumulation (12 g m
2
year
−1
). If the future climate will be warmer and wetter, then regional mires are likely to remain a carbon sink, alternatively, a reversion to the wooded state with reduced carbon sink strength is possible.
A better understanding of past long-term environmental changes in the subarctic region is crucial for mitigation of the possible negative effects of climate warming in this vulnerable region. This ...study provides a new multi-proxy reconstruction of regional vegetation changes and peatland development for north-eastern Fennoscandia (Russia) during most of the Holocene. To that purpose, we performed plant macrofossil, pollen, testate amoebae, peat humification, loss on ignition and radiocarbon analyses of the peat deposits from a mire around Vodoprovodnoe Lake (the Kindo Peninsula, the Republic of Karelia). Our data indicate that the peat deposits started accumulating before 9147 ± 182 cal. yr. BP. The vegetation cover in the area was mainly typical for the northern taiga zone, except for the period ~7800–5600 cal. yr. BP, when it generally resembled the middle taiga zone. The vegetation cover and peatland were greatly affected by reoccurring fires, which can be partly related to human activity. These events were associated with an increased proportion of birch in the vegetation cover (as a pioneer species) and/or water level decreases. By 600 cal. yr. BP, the peatland and the surrounding vegetation reached its current state and only minor changes had been recorded since that time. Overall, our results suggest a considerable and unexpected role of fires in the postglacial dynamics of subarctic peatlands.
The Kamchatka Peninsula in the far east of Russia is a substantial landmass that is poorly documented in terms of most elements of biodiversity. Here we provide the first study of modern assemblages ...of testate amoebae, a widespread group of protists that are particularly abundant in soils. We present a data set of 78 widely distributed samples, including forest, fen, scrub and bog habitats. Testate amoebae are abundant and diverse across Kamchatka with 119 taxa identified. The assemblage is primarily composed of widespread taxa, but rarer occurrences such as Cyclopyxis puteus hint at important biogeographical differences that will require confirmation with molecular data. Assemblages from mineral soils are significantly different from those of peatlands with the former characterized by small idiosome taxa and the latter by larger taxa, often with secretion tests. Water table depth explained significant variance in the peatland samples, supporting the use of testate amoebae in palaeoecological studies. This study adds to our knowledge of the biodiversity of Kamchatka and the global biogeography of protists, and it paves the way for palaeoecological studies to understand long‐term environmental change in this region.
Testate amoebae (TA) are important components of soil ecosystems, where they play an essential role in belowground food webs. In this study, we examined species composition, diversity, and structure ...of TA assemblages in soils beneath tree crowns (microscale) at three slope positions (mesoscale) in subtropical urban parks in Shenzhen, China. Forty-two species of TA belonging to 18 genera were identified in 81 samples. TA assemblages were the most diverse and abundant in the center of the tree crown comparing with other under-tree habitats. Foot of the hills harbored higher TA abundance and diversity comparing with upper locations along the hillslopes. The distribution of TA was mostly driven by under-crown and hillside positions but not by elementary environmental conditions such as pH, moisture content and thickness of leaf litter layer. None of later factors were sufficient in shaping TA assemblage composition. The findings of our study suggest that in regional studies of soil microbial eukaryotes both micro- (i.e., under-crown) and mesoscale (i.e., the slope position) heterogeneity should be considered.
Climate, fire, and human activities strongly affected the development of vegetation communities during the Holocene, yet the relative importance of these individual factors remains unclear in many ...areas. This paper presents new multi-proxy records of environmental change for the Meshchera Lowlands (the central part of the East European Plain) during the Holocene. Changes in regional vegetation during the Mid- and Late Holocene were influenced by climate, fire regime and human impact, as indicated by pollen, plant macrofossil, charcoal and testate amoebae analysis from several peat cores, along with reconstruction of tree cover from pollen assemblages. Since 8500calyrBP, the vegetation history represented a series of consecutive phases of birch, birch-pine and pine-broadleaf forests, with introduction of spruce after 2500calyrBP. Maximal abundance of broadleaf tree species was detected from 4700 to 2000calyrBP. Vegetation dynamics were strongly influenced by human activity since 1400calyrBP. High fire frequency was recorded for the periods 8500–4500calyrBP and 3500–2000calyrBP, when the fire return interval varied from 40 to 80years. Since 2000calyrBP, the fire return period exceeded 500years suggesting a significant decline in fire frequency during the last two millennia.
•New data on the paleoenvironmental changes in the central European Russia are presented.•The first reconstructions of the Holocene fire frequencies in the Meshchera Lowlands•The Mid- and Late Holocene vegetation changes were mainly influenced by climate changes and fire regime.•Vegetation dynamics were strongly influenced by human activity since 1400calyrBP.•The fire frequencies was high during 8500–5000calyrBP and 3000–2000calyrBP and reduced during the last 2000calyrBP.
The paper describes a dataset, comprising 236 surface moss samples and 143 testate amoeba taxa. The samples were collected in 11 Sphagnum-dominated bogs during frost-free seasons of 2004, 2007, 2009, ...2017, and 2022. For the whole dataset, the sampling effort was sufficient in terms of observed species richness (143 species in total), though a regional species pool is deemed to be discovered incompletely (143 species is its lower 95 % confidence limit using Chao’s estimator). The local community composition demonstrated high heterogeneity in a reduced ordination space. It supports the opinion that the high versatility of bog ecosystems should be taken into account during ecological studies.
Abstract
High-latitude peatlands are changing rapidly in response to climate change, including permafrost thaw. Here, we reconstruct hydrological conditions since the seventeenth century using ...testate amoeba data from 103 high-latitude peat archives. We show that 54% of the peatlands have been drying and 32% have been wetting over this period, illustrating the complex ecohydrological dynamics of high latitude peatlands and their highly uncertain responses to a warming climate.
PDF
