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Actinobacteria living in frozen soils which potentially could be producers of valuable and biologically active metabolites, remain still largely unexplored. Therefore, the diversity of culturable actinobacteria in the six frozen soil samples collected from the high-latitude and the high-altitude regions in China was investigated by using the culture-dependent method and 16S rRNA gene analysis. A total of 184 culturable actinobacterial isolates (morphotypes) were obtained. The abundance of culturable actinobacteria was 6.20 × 103–3.49 × 105 colony forming units (CFU) per gram of soil (dry weight). The actinobacteria isolated from the high-latitude region in China belong to five genera: Streptacidiphilus, Kitasatospora, Streptomyces, Arthrobacter, and Rhodococcus. The strains belonging to Arthrobacter were dominant, the 19 strains were closely related to Arthrobacter globiformis in terms of evolutionary distance. The actinobacterial isolates from the high-altitude region, from 2, 813 m to 4, 775 m in elevation, in China could be grouped into six genera (Arthrobacter, Microbacterium, Streptomyces, Rhodococcus, Nocardia, and Nocardiopsis), with dominant Streptomyces and Arthrobacter strains. The 4 strains were closely related to Rhodococcus fascians and one strain was closely with Microbacterium hydrocarbonoxydans in terms of evolutionary distance. Three genera of Arthrobacter, Streptomyces, and Rhodococcus were found in both areas. Our research provides new insight into the characteristics of the distribution of actinobacteria associated with frozen soils, which help us gain a better understanding of the potential of the cryogenic environments – the potential source of actinobacterial antibiotics.
The aim of the study was to estimate the effect of habitat factors such as moisture conditions and some physicochemical soil characteristics on the structure of the vegetation and the soil seed bank, and to compare species composition of the vegetation cover and the seed bank along the soil moisture and fertility gradients in closed depression in agricultural landscape. Based on the averaged results of the extent and time of stagnation of the water, along the transect four habitat moisture zones were distinguished (dry, periodically moist, moist, and wet). In eighteen study plots we analysed flora, soil seed bank, and contents of Ca, Mg, K, Mn, Fe and pH of the soil. The analysed closed depression is characterised by high variability in moisture conditions and in the physical and chemical properties of the soil. The most important factors affecting the diversity of the vegetation cover and seed bank were the duration of water stagnation and the content of Fe and Mn in the soil. The lowest plant species richness and the smallest seed resources were determined for the wet zone of the depression. An increase in the habitat moisture level was accompanied by a decline in the floristic similarity between the vegetation cover and the seed bank.
Understanding the role of plant diversity in maintaining vegetation cover is a central focus of assessing the vegetation dynamics of grasslands. The present study assessed the relationship between species richness and vegetation cover, as well as underlying biological mechanisms in three Mongolian grasslands, namely meadow, dry steppe and mountain steppe.
Each of three grasslands was set by two treatments: grazing exclusion by fence and freely grazing. I measured plant species richness, vegetation cover, height and phenology. I examined three biological mechanisms, namely plant interactions, the role of dominant species and vegetation growth periods.
The results showed that higher species richness generally increased vegetation cover independent of fencing treatment and grassland type. Plant interactions were the strongest in fenced plots of the mountain steppe. Dominant plant species invested more in vegetation cover rather than the height in grazed plots than fenced ones in Mongolian grasslands. Taking vegetation growth periods into account did not alter the strength and the direction of the relationship between species richness and vegetation cover. I thus infer that examining changes in species diversity will allow for a better understanding of vegetation cover dynamics in grasslands. This will help to assess how ecosystem functioning might be impacted by grazing disturbances in Mongolia.
Despite the high taxonomic diversity, wide distribution and important ecosystem functions of snails, their ecology remains obscure, and this can hamper their conservation. Overwintering in the studied population of Vertigo moulinsiana is effective enough to allow the majority of it to survive. The population dynamics of V. moulinsiana is specific, where the summer boom in a suboptimal habitat covering a small area (wet patches of sweet grass) can determine the snail's range over much larger areas. Our results suggest that humidity could have been the major factor governing population increase. The summer boom is caused by juveniles appearing in very large numbers during this period, thus the peak height is mostly influenced by the considerable susceptibility of juveniles and eggs to desiccation. The limiting influence of humidity is evident in the unequal spatial distribution of individuals: the wetter the substrate, the greater the abundance of snails. As a consequence, the boom may be spatially regulated and only occurs in wet habitats, even though the snail actually occupies a much larger area. Our results indicate that this V. moulinsiana population does not follow typical models constructed for vertebrates or other animals with high dispersal abilities, like the Ideal Free Distribution (IFD) model, and requires a specific approach. Its specific spatiotemporal pattern should be taken into account during monitoring surveys and conservation actions.
Long-eared owls (Asio otus) are common avian predators in Turkey. Their diet consists primarily of small mammals, but they also feed on bats, birds, amphibians, reptiles, insects, and fish. Limited research has been conducted on long-eared owl diets and pellet characteristics in Turkey, yet this knowledge would improve our understanding of their ecological role in the environment. We investigated prey items in pellets at winter sites of Asio otus in Edirne, Kirklareli, Tekirdag, and Istanbul. We collected 2143 pellets from winter sites and counted 3458 prey items. We identified 30 taxa including 16 mammals, 12 birds and 2 insects. Asio otus primarily consumed small mammal species (97.9%) which consisted mainly of rodents (89.6%, including Cricetidae 45.95%, Muridae 43.7%), Eulipotyphla (1.2%), and unidentified mammals (7.1%). A small proportion of birds (1.9%) and insects (0.2%) also were consumed. Asio otus inhabited small coniferous woodlands at edge of farmlands during winter, but their diet varied with location. Muridae were primarily consumed in Istanbul and Tekirdag, whereas Cricetidae were mostly consumed in Kırklareli and Edirne. Our study shows that Asio otus feeding habits shift depending on prey abundance and that they are not specialists for Microtus species only.
In larger river valleys of southern Africa, riparian forests are among the main vegetation types. The forests are regarded as ones of the most diverse and distinct terrestrial habitats on earth. They also play a crucial role in wildlife conservation as corridors and refugia for wildlife. It is hypothesized that the closer to the river bank, the higher the species diversity, while population densities may increase with the increase of the distance from the river bank. In 2014, quantitative studies (by means of the mapping method) on avian community breeding in such forest on Zambezi River in Katima Mulilo were undertaken to measure this gradient. Four plots were designed along an increasing distance from the river bank in this forest. In terms of the number of species, there was a significant gradual decrease with the increasing distance from the bank (from 91 to 54 species). The number of breeding pairs per 100 ha increased with the moisture gradient (from 222 to 677). Shannon's (H') and Simpson's (D) indices were higher in the two plots closer to the bank river (H'= 3.44–3.85; D = 0.97–0.99), than in the two remaining plots (H' = 3.13–3.15; D = 0.92–0.93). Also the Pielou's Evenness Index was higher in two plots closer to the bank (J' = 0.84–0.85 vs. 0.77–0.78). The proportion of granivores in the avian community declined along the moisture gradient, while that of insectivores and frugivores – increased. These gradual changes can be linked to a parallel gradual changes of the amount of fruits and invertebrates.
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