Detection of DNA of borrelia circulating in Novosibirsk region

Detection of DNA of Borrelia burgdorferi sensu lato was performed by PCR in taiga ticks Ixodes persulcatus, in blood samples and skin bioptates of small forest mammals, and in blood and urine samples of humans after attaching of ticks events. In Novosibirsk region both in natural reservoir and in patients with Ixodes ticks-borne borreliosis DNA of Borrelia garinii and Borrelia afzelii are detected. DNA of these borrelia were detected in 8 from 72 of taiga ticks, in 36 from 298 of blood and skin samples of small forest mammals, and in 32 from 102 of human blood and urine samples. In all studied samples DNA of B. garinii from NT29 subgroup was predominated. Borrelia DNA in which sequence of intergenic spacer region was homologous to sequence Chy13p first detected in China has been detected in one blood sample from red-backed vole (Clethrionomys rutilus).     

Effects of bryophytes and grass litter on seedling emergence vary by vertical seed position and seed size

Establishment of plants through seeds is often constrained by the quality of microsites, which is in part controlled by the nature and amount of ground cover. The latter consists of living shoots of vascular plants or bryophytes and/or the dead remains of the dominant species. In the present article, we report the results of a controlled pot experiment with five species characteristic of floodplain grasslands. We manipulated the amounts of grass litter and/or mosses to study (1) differences between ground cover types with respect to their effects on microenvironment and seedling emergence and (2) how these effects interact with seed size and seed sowing position. Increasing amounts of both cover types led to increasing soil humidity, whereas temperature amplitude and illumination were decreased. However, since grass litter decomposed much faster than bryophytes, light conditions for germination under grass litter improved considerably with time. Although seedling emergence varied significantly between species, ground cover types and cover amounts, seed position alone explained about 50% of the variation in the data set. Additionally, we found an important interaction between seed size, seed position and cover type: large-seeded species showed a fitness advantage when seeds were situated beneath a cover, irrespective of cover type, which disappeared when seeds were shed on top of a cover layer. We suggest that this interaction may be ecologically and evolutionarily relevant because it may lead to changes in species composition and diversity of plant communities as a consequence of changes in the amount and type of ground cover.     

Importance of site conditions and time since abandonment for coppice vegetation on Langeland, Denmark

In 57 sample plots in neglected coppices on Langeland, Denmark (14—c. 125 years since last coppicing) the cover of trees and shrubs was analysed by the method of Domin-Krajina and the ground layer by the frequency method of Raunkiær. The data were analysed by DC A. The tree and shrub layer showed significant correlations with topsoil pH and litter depth. The ground layer was significantly correlated with inclination, area of the wood in which the coppice was situated, light, topsoil pH and the tree layer, and to a lesser extent with litter depth, but was not correlated with time since last coppicing. It is suggested that for some stands the suppression of Corγlus avellana by tree species ( Quercus robur, Fagus sylvatica, Carpinus betulus ) which form a permanent litter layer and acidify the soil is more important to the ground layer than the time elapsed since last coppicing per se. Formation of a permanent litter layer reduces species density, e-specially of some forest species without clonal growth. One main reason for the lack of correlation between the ground layer and time since coppicing may be the great environmental variation in the neglected coppices on Langeland. Another reason seems to be the absence of competitive forest species (which otherwise would benefit from non-intervention) due to the isolated position of the coppiced woods. It is concluded that neglect in excess of c. 35 years beyond the normal coppice rotation has some effect on the composition of the tree and shrub layer, but not a direct effect on the ground layer.     

Studies on the ecology of Amblyomma marmoreum Koch 1844 (Acarnia: Ixodidae).

In the Eastern Cape Province of South Africa, larvae and nymphs of Ablyomma marmoreum Koch occur in habitats in which there is tree cover and herbaceous ground cover. Immatures of A. marmoreum are parasitic on reptiles, birds, and mammals. Adults occur only on reptiles. The major host for all stages is the moutain tortoise (Geochelone pardalis), and in the home areas of tortoises the density of ticks is high. Larvae are active in late summer and autumn. The rate of feeding is temperature-dependent, and some larvae which attach on tortoises in late autumn do not complete feeding until the following spring. Nymphs which occur in the home area of a tortoise become active in response to CO2 in early spring. Adults, and nymphs which occur outside the home area of a tortoise, become active in summer in response to rising temperatures. In nymphs which feed in spring, and hence develop into adults in midsummer, the life cycle is completed in 1 year. In nymphs which fed in midsummer, the life cycle is completed in 2 years.     

Spatial distribution of the Karoo paralysis tickIxodes rubicundus (Acari: Ixodidae) within a false upper Karoo veld type

Spatial distribution of the Karoo paralysis tick (Ixodes rubicundus) has been studied in a paralysis enzootic area of the southwestern Orange Free state. Significantly more females than males were collected from the vegetation. Most ticks (99%) used grass as questing sites at a height of approximately 45 cm (range 10–97 cm), which correlates with the size of host animals. No significant differences between the questing height of male and fermale ticks were evident. The ticks were found on most of the grass species present and, except for the genusEragrostis no specific preference was evident. When questing, the capitulum ofI. rubicundus is usually (90%) directed towards the ground. Seventy-eight percent of the ticks occurred singly on a specific grassblade or flowerhead. In those cases where two ticks occurred together, no sexual aggregation was evident. Most ticks occurred under or close ( =62 cm) to the corwn cover of specific shrub or tree species. These plant species were characterized by a dense crown cover with a mat of decaying leaf litter underneath. The preference of the tick for wild olive trees (Olea europaea fricana) suggests that except for the physical characteristics of this tree species, host factors may also be important. Significantly more ticks were distributed on the cooler, more protected southern sides of vegetation in comparison to the northern sides.     

Ecological and Biological Features of Soils in Fir Forests Defoliated by the Siberian Moth in the Southern Taiga Subzone of Middle Siberia

Experimental data are analyzed that concern the effect of zoogenic debris on the properties of soddy deep podzolic soils and raw-humus brown soils characteristic of southern taiga forests in the Yenisei region of Siberia. It is shown that the influence of excrements of Siberian moth larvae on the soil microflora lasts for two or, at most, three growing seasons. Zoogenic plant debris falling on the ground surface during tree stand defoliation is a short-acting but powerful stimulant of biological activity in the litter; hence, it has a considerable effect on soil properties. This effect is enhanced by changes in ecological conditions that occur upon defoliation. The influence of the cenotic factor on biogenic soil properties is manifested more strongly in the organogenic horizons. The communities of microorganisms involved in the nitrogen and carbon cycles are dominated by prototrophic forms in the normal fir forest and by pedotrophic forms in the forest defoliated by pests.     

Ground vegetation in the Mongolian taiga forest‐steppe ecotone does not offer evidence for the human origin of grasslands

Question: Is the vegetation of meadow and mountain steppes distinct from the ground vegetation of light taiga forests in the transitional zone between these biomes? Location: Western Khentey Mountains, northern Mongolia. Methods: Vegetation was recorded from 100‐m² plots from all dominant types of light taiga forest and dry grassland. Distinctness of ground vegetation was studied with Detrended Correspondence Analysis (DCA). Results: Ground vegetation in the light taiga was significantly different from the herbal vegetation of meadow and mountain steppes. Clear separation was only absent for the Car ex amgunensis meadow steppes that occur in a narrow strip along the forest edge and are partly shaded by trees. Forest and steppe communities followed a moisture gradient according to the DCA ordination with light taiga forests at the moistest sites and steppe communities at the driest sites. Ulmus pumila open woodlands diverged from this pattern, because of their close spatial and phytosociological relationship to mountain steppes. Conclusions: The present results do not support the assumption that grasslands in Mongolia's transitional zone between forest and steppe would generally resemble the ground vegetation of light taiga forests. This contradicts a published hypothesis stating that the vegetation of meadow and mountain steppes would not clearly differ from ground vegetation of light taiga forests in the forest‐steppe transitional zone of Mongolia.     

凋落物和土壤覆盖对动物取食和搬运辽东栎种子的影响

在六盘山区的华北落叶松人工林,研究了清除凋落物、凋落物覆盖和土壤覆盖(以不清除凋落物直接将种子投放于森林地表为对照)等处理对动物取食和搬运辽东栎种子的影响.结果表明:种子释放3d后,凋落物和土壤覆盖处理种子均具有较高的留存率(分别为10.7％和7.0％);释放14 d后,土壤覆盖处理种子的留存率仍最高(0.7％),但凋落物覆盖处理种子的留存率为0.凋落物和土壤覆盖处理种子的就地取食率很高(分别为45.9％和41.5％);清除凋落物处理种子的就地取食率最低(27.0％),但其被搬运后的取食率最高(49.8％);凋落物覆盖、清除凋落物和土壤覆盖处理种子被动物搬运后的埋藏率均显著高于对照(P＜0.01).种子被动物搬运后集中分布于5 m以内,尤其在＜1 m和l～2m两个距离组的分布频率更高;种子被搬运后取食的平均距离大干埋藏的平均距离,以土壤覆盖和凋落物覆盖处理最大,分别为2.38 m±0.55 m和1.44m±0.26 m.     

Aggregation in the questing tick, Rhipicephalus pulchellus

ABSTRACT. The ixodid tick, Rhipicephalus pulchellus (Ixodidae) can be observed aggregated on the tips of grass stems in the field in Kenya. From laboratory experiments, Browning (1976) concluded that these aggregations were the result of ticks having first aggregated on the ground if provided with sufficient cover. During our extension of Browning's experiments using several types of cover, the ticks did not exhibit aggregating behaviour. The influence of the presence of a human observer on the activity of the ticks, however, became apparent.     

The effect of oil extraction on ground cover of West Siberian taiga forests

The study explored the effect of oil pollution, soil salinization, and waterlogging on ground cover of green-moss forests in West Siberian middle and northern taiga. These disturbances reduce the total abundance and biological productivity of ground cover, taxonomic richness, and change roles of some species and plant groups in communities.     

Zoological prerequisites of human tick-borne infections in the Northern Urals

The results of studies in the pessimum of the taiga tick (Ixodes persulcatus Sch., 1930) range in the Urals have shown that this species occurs in the regions at latitudes of up to 60°50′ N. In Northern Ural mountains, the ticks show preference for secondary small-leaved forests growing on southern slopes, where their abundance along census routes reaches 7 ind./km. The abundance and distribution of taiga ticks hosts, birds and small mammals, have been estimated in the main types of their habitats. Larvae and nymphs of the taiga tick have been found on nine bird and seven small mammal species, with the main parasitic load falling on the northern red-backed vole (Clethrionomys rutilus P., 1779), which is widespread and abundant in the greater part of the study area. Molecular biological analysis of I. persulcatus ticks and blood samples from their hosts has revealed the presence of nucleic acids of pathogenic microorganisms A. phagocytophilum, E. muris, and A. burgdorferi sensu lato, the RNA of tick-borne encephalitis virus, and the DNA of Babesia microti.     

Recovery of ground vegetation at the initial stage of fire succession

The impact of surface fires varying intensity on the living ground vegetation in the middle-taiga forests of Central Siberia are studied. It is revealed that fires, regardless of their intensity, decrease the percentage cover and the biomass of living ground vegetation; they also destroy the moss and lichen layer. The postfire recovery of the ground vegetation at the initial stage of postfire succession is determined by the prefire forest type, the fire intensity, and the burn depth of the litter.     

Reason for fluctuation in the demographic structure of the taiga tick population (Ixodidae) in dark conifer-leaf forests of Kemchug Upland

It was found out, that mean ratio of unfed taiga ticks Ixodes persulcatus having a life cycle of 3-5 and 6 years counts respectively (N = 6) 33.6, 52.8, 13.2 and 0.4%. Data on absolute number of I. persulcatus individuals in the process of onthogenesis is given. It is shown, that mortality of different unfed stages increases from larva to imago. In the autumn-winter period, the mean ratio of eliminated individuals counted 16% of larvae, 20% of nymphs, and 38 of imago. The mortality in the spring-summer period caused mainly by the deficit of hosts and counted for these stages 3, 82 and 98% respectively. Engorged ticks successfully undertake unfavorable conditions both in the spring-summer and autumn-winter periods. Their mean mortality in the period from feeding to moulting does not exceed 12%.     

浙江天童常绿阔叶林地被层的研究

 对天童常绿阔叶林地被层植物种类组成及群落学作用进行了初步研究。研究表明：组成地被层计有维管植物44科78属114种。蕨类植物优势度最大,里白占绝对优势。39种草木植物,以世界分布科和地面芽植物为主,常绿种类占84.6％,未见亚洲和北美洲间断分布的地理成分。乔灌木幼苗51种,80%的苗量集中于4～6个种中,优势种突出。藤本植物24种,草质藤本占25％,落叶种类42％。地面苔藓植物(22种)与枯枝落叶构成镶嵌分布,发育较成熟的群落中苔藓种类多,盖度大。里白及其枯死物形成层层交错重叠的地被层,阻碍凋落物进入地表,减弱光照,使近地表光照长期低于幼苗光补偿点,抑制了乔灌木优势种的更新。凋落物阻碍种子下移至半分解层,栲树种子下移率为17％至22.3％,冬季种子的动物损耗率平均为98.2％,凋落物中种子的平均腐烂率为28.2％,表层保存下来的栲树种子因缺水萌发速度慢且成活率低,下层萌发速度虽快,但腐烂率高,栲树天然更新幼苗主要来源于草窗。     

Reintroduction of Wild Lupine (Lupinus perennis L.) Depends on Variation in Canopy,Vegetation, and Litter Cover

We experimentally examined the effects of canopy, vegetation, and leaf litter cover on the demography of Wild lupines (Lupinus perennis) in a central North American oak savanna spanning 9 years. We also compared the distribution of Wild lupine across the landscape to results predicted by the demographic experiments. With less canopy cover, soil temperatures were warmer and seedlings emerged earlier. Seedling survival increased 14% with each additional leaf grown. Seedling survival was four times greater in openings and partial shade than in dense shade. Seedling survival was also influenced by interactions between canopy cover and vegetation cover, between canopy cover and leaf litter, and among canopy cover, vegetation cover, and litter cover. In openings, seedlings had higher survival when vegetative cover was present, suggesting a positive shading effect on survival, but with greater canopy cover vegetative cover reduced survival. Seedling survival was greater for plants that experienced herbivory, a result that was probably related to plant size and quality rather than having been eaten. Survival of lupines to 9 years after seed planting was greatest in the partial shade, moderate in openings, and least in dense shade. Wild lupine cover across the landscape was greatest when litter cover was low and canopy cover and ground layer cover were moderate. Reduction of canopy cover by burning or cutting, and reduction of leaf litter by prescribed burning will benefit the reintroduction of Wild lupine by increasing light, reducing litter cover, and creating disturbances; however, the reduction of vegetation cover in openings may hinder lupine reintroduction.     

死、活地被物对红松伴生树种天然更新影响的实验研究

1963年在小兴安岭丰林自然保护区红松林及有关的皆伐迹地上设置了61组,325个实验样方,定期观察到1965年,以研究死、活地被物对人工播种的红松林伴生树种种子发芽和幼苗初期存活、生长的影响。实验表明死、活地被物,特别是死地被物的干湿变化剧烈,影响幼苗的成活,甚至使种子或幼根无法接触土壤,因而种粒越小,或轻而带翅,受影响越大。此外本文还指出了桦树种子的强迫休眠和延迟发芽现象。讨论了实验结果在红松林演替和人工促进天然更新中的意义。     

Seed–litter–position drives seedling establishment in grassland species under recurrent drought

Changes in land use and climate interfere with grassland ecosystem processes. Here I experimentally investigated the combined effects of land‐use change related litter cover and contrasting water supply on seedling emergence. In this context, the role of the initial relative position of seeds, i.e. seeds on top of the litter versus seeds beneath the litter in interaction with water supply has not been investigated so far. I hypothesised that facilitative effects of litter on seedling emergence occur when seeds are covered by litter and deteriorate when litter covers the ground and seeds fall on it (seeds on top of the litter). Further, I hypothesised that the importance of seed position for seedling emergence will increase under conditions of recurrent drought. I performed a controlled pot experiment on seedling emergence of three common European grassland species (Pimpinella saxifraga, Leontodon autumnalis, Sanguisorba officinalis) by experimental manipulations of litter and water availability. Seedling emergence under moist conditions showed no significant differences between each litter position compared to the control across species. In contrast, under recurrent drought, seedling emergence was significantly higher below the litter compared to seeds on top of the litter and the control (i.e. no litter). In abandoned land, seedling emergence may be limited when seeds fall on ground‐covering litter. In contrast, in grasslands with regular low‐intensity land use, seedling emergence may be enhanced when a moderate level of litter covers seeds at the end of the growing season. Protective mechanisms that occur with seeds positioned beneath litter are particularly important under recurrent drought.     

The possibility of the detection of one more tick-borne infection--babesiosis--on the territory of Russia

A total of 739 taiga ticks of ixodes persulcatus species, obtained in the recreational zone of St. Petersburg, were studied for the presence of Babesia sp. with polymerase chain reaction. All these ticks underwent the preliminary examination for the presence of Borrelia (3 species), Ehrlichia (2 species) and tick-borne encephalitis (TBE) virus. In 7 cases Babesia were detected among 413 ticks containing other pathogens. Among 326 ticks no Babesia were detected, as well as no other pathogens. All ticks having Babesia were also found to contain Borrelia species: B. afzelii, B. garinii, or both (1 case). In one female tick, in addition to Babesia, also B. garinii and TBE virus were determined. The data thus obtained should draw special attention not only of parasitologists, epidemiologists and microbiologists studying ticks obtained from natural sources, but also of clinicists who should consider the possibility of mixed infection, when one infection may mask the presence of some other infection, in particular babesiosis. Due to rare occurrence of Babesia in ticks and the presence of mixed infection difficulties may arise in the detection of Babesia.     

Conjugated variability of spontaneous activity and behavioral response to olfactory stimuli in the taiga tick (Ixodes persulcatus)

According to the automatic tracing of the movement of ticks in a Petri dish, motivational variability of the spontaneous activity and behavioral response of the taiga tick to olfactory stimuli was analyzed. In the studied sample, two groups of ticks that differ in the movement trajectory in the absence of stimulus were isolated, including ticks that mainly moved on the edge of the dish at maximum accessible height (group 1) and ticks that mainly moved at the bottom and wall of the dish (group 2). It was registered that ticks of group 1 (as opposed to ticks of group 2) demonstrated a pronounced behavioral response to olfactory stimuli (human synthetic pheromones and ammonia) and negative geotaxis. It was established that belonging to these groups depended on the time of day when the testing was performed and did not depend on the physiological age and infectious status.     

Long-term dynamics of the epizootic process in natural foci of ixodid tick borreliosis in mountain taiga forests of the Middle Ural

During eleven spring-summer seasons (1992-2002), the dynamics of the epizootic process in natural foci of ixodid tick-borne borrelioses (ITBB) were studied in taiga forests of the Middle Ural (Perm Province, Russia). In these foci, Borrelia garinii and B. afzelii circulate, and their main vector is the Ixodes persulcatus tick. Main parameters of the epizootic process were calculated for each season. In four seasons (1993, 1996, 1999 and 2002), the parameters characterizing the abundance of unfed nymphs and adult ticks, as well as the prevalence of Borrelia in them, density of infected ticks, and approximate total number of Borrelia in them proved to increase essentially and simultaneously. These seasons were preceded by the years of population peaks in forest small mammals (1992, 1995, 1998 and 2001), especially in the Clethrionomys glareolus vole, the dominant species in the local fauna of these mammals and the main reservoir host of Borrelia. Apparently, the possibility of horizontal transmission of the ITBB agents sharply increased in such years, and this resulted in the intensification of their dissemination.