Structural-functional organization of the soil mesofauna population in bogs and waterlogged forests of northwestern Karelia

The soil mesofauna was studied in two ecological series (oligotrophic and mesotrophic) of bogs in northwestern Karelia. The earlier found differences in the structural-functional organization of the soil mesofauna in the bogs investigated were confirmed. The high indices of the taxonomic diversity and abundance of mesopedobionts were characteristic of the mesotrophic biogeocenoses. Among the factors limiting the activity of the mesopedobionts, the hydrothermal regime and soil acidity played the leading part. In the series of the bog biogeocenoses studied, the abundance of mesopedobionts increased with the increasing soil acidity, lowering the groundwater table and decreasing the content of sodium extracted by the ammonium acetate solution. Zoophages predominated in the trophic structure of the oligotrophic bogs due to the unfavorable conditions for large invertebrates there; in the mesotrophic bogs, myxophages were the dominants. The abundance of myxophages increased in the mesotrophic series simultaneously with the increasing nitrogen content in the soil mesofauna-inhabited soil horizons. In the mesotrophic biogeocenoses, saprophages were not numerous (one species of litter earthworms). Probably, in the bog soils, they are substituted for myxophages.     

Conserving the benefits of predator biodiversity

Organisms at higher trophic levels often face a disproportionate risk of local or regional extinction, while at the same time many ecosystems are being invaded by non-native predators. Global environmental change fosters both processes, further altering predator biodiversity. Thus, there has been growing interest in how predator species richness impacts ecosystem functioning. Manipulative experiments have revealed that complementarity and sampling effects, two mechanisms commonly found to underlie diversity effects at other trophic levels, also commonly impact the relationship between predator diversity and prey suppression. Intraguild predation and non-consumptive (behaviorally-mediated) effects on prey, two mechanisms without direct analogs among plants, also strongly impact predator-diversity effects. Predator diversity studies are particularly relevant to conservation because they focus on the trophic group that is most prone to extinction, and because they nearly always measure diversity effects that span several trophic levels. Predator invasions may partly offset species-richness losses to extinction, but because invasive predators typically reach much higher densities and exert stronger impacts on prey than do native species, and because they also displace ecologically-similar native predators, invasion is likely to disrupt natural predator function. A framework for predicting which predator-diversity mechanisms are likely to operate in a given community, and experiments that span more realistic spatiotemporal scales and include large vertebrate predators, are needed to improve the relevance of predator-diversity experiments to conservation decision-making in the future.     

The importance of mycological studies for soil quality control

Published and original data obtained in the course of long-term studies of mycobiota of several soil types in regions with different pollution levels and composition of the pollutants (Tver, Moscow, and Samara oblasts; West Siberia; and the Komi Republic) are analyzed. The expediency of using mycological characteristics for soil quality control and estimation of the toxic impact on the environment is discussed. The most pollutant-sensitive mycological characteristics were determined for the following soils: oligotrophic peat gley, eutrophic peat, whitish podzolic, Al-Fe-humus podzol, soddy pale podzolic, soddy-podzolic, and brown forest soils. These are (a) the structure of the fungal biomass, (b) the taxonomic diversity of the fungi, and (c) the percentage of melanized forms of micromycetes. At the same time, the total number of fungi (in colony-forming units) and the indices of the richness of individual species and genera proved to be poorly informative for assessing the ecological status of the soils. Criteria for the choice of mycobiotic parameters suitable for scaling the soil ecological quality are suggested.     

The effect of pollution with oil and oil products on the biological status of ordinary chernozems

The effect of pollution of an ordinary chernozem with oil and oil products depends on the nature and concentration of the pollutants, their distribution in the soil profile, and the period of the pollution. The soil contamination causes a rise in the number of microorganisms and changes in their species composition: a decrease in the diversity of micromycetes and an increase in the diversity of bacteria. In most cases, it inhibits the activity of soil enzymes. Oxidoreductases are more sensitive to oil pollution than hydrolases. The soil ecological functions are disturbed under the impact of contamination.     

Worldwide genotyping of castor bean germplasm (<Emphasis Type="Italic">Ricinus communis</Emphasis> L.) using AFLPs and SSRs

Worldwide genetic diversity in 200 individuals comprising 41 castor bean accessions was assessed using amplified fragment polymorphisms (AFLPs) and simple sequence repeats (SSRs). We found that, despite surveying five continents and 35 countries, genetic diversity in castor bean germplasm is relatively low (overall H _e = 0.126 for AFLPs and 0.188 for SSRs) compared to estimates of genetic diversity in other plant species. Our data also show no geographic structuring of genotypes across continents or countries within continents. An assessment of the congruence between AFLP and SSRs indicates a low correlation (R ² = 0.19) between the two data sets, but each marker class nonetheless shows similar patterns of low-genetic diversity and a lack of geographic structure. Our data do suggest that SSRs yield a higher percentage of polymorphic loci, higher heterozyosity and a greater range of genetic distances, and are therefore more informative than are AFLPs on a locus-by-locus basis. Based on comparisons with numerous other plant species, we suggest that the lower genetic variation in this worldwide collection may be due to one or more factors including: sampling strategies that have not captured the full extent of genetic variation in the species; artifactual variation due to long-term germplasm storage and seed regeneration; or intense selection followed by domestic cultivation of a limited number of castor bean genotypes, which are widely propagated for their horticultural and agro-economic value.     

Grazing promotes dung beetle diversity in the xeric landscape of a Mexican Biosphere Reserve

We analyze the impact of grazing on dung beetle diversity at the Barranca de Metztitlán Biosphere Reserve, a xeric ecosystem in central Mexico with a long history of use by humans. We compared the community structure, as well as the alpha and beta diversity between two cover conditions (open and closed vegetation) that represent the impact of grazing within a habitat, and between habitat types (submountainous and crassicaule scrublands). From 576 samples we collected 75,605 dung beetles belonging to 20 taxa. While mean species richness and diversity were different between habitat types, cumulative species richness was not. The effects of grazing on vegetation structure influenced the cumulative species richness and diversity of dung beetles in the submountainous scrubland, where grazing has created land mosaics of a grassland matrix with scrubland patches. This was not the case in the crassicaule scrubland where the impact of grazing is not as evident. Beta diversity significantly responds to the effects of grazing on habitat conditions. We discuss the ecological factors that may promote these responses by landscape diversity components. We also identify the species that could act as useful indicators to monitor the effect of land management on biodiversity. Our results indicate cattle farming maintains a diversified land mosaic, and these areas support more diverse dung beetle ensembles than homogeneous areas of closed, shrubby vegetation cover. Thus, controlled grazing activity could certainly favour the conservation of dung beetle biodiversity and improve ecosystem functioning by maintaining dung decomposition rates.     

Fungal communities in the soils of early medieval settlements in the taiga zone

The difference between the mycobiota in anthropogenically transformed soils of the settlements of the 9th–14th centuries and in the background zonal Podzols and umbric Albeluvisols of the middle and southern taiga subzones in the European part of Russia is demonstrated. The mycological specificity of anthropogenically transformed soils with a cultural layer (CL) in comparison with the background soils is similar for all the studied objects. Its characteristic features are as follows: (1) the redistribution of the fungal biomass in the profile of anthropogenically transformed soils in comparison with zonal soils, (2) the lower amount of fungal mycelium in the CL with the accumulation of fungal spores in this layer, (3) the increased species diversity of fungal communities in the CL manifested by the greater morphological diversity of the spore pool and by the greater diversity of the fungi grown on nutrient media, (4) the change in the composition and species structure of fungal communities in the CL, (5) the replacement of dominant species typical of the zonal soils by eurytopic species, and (6) the significant difference between the fungal communities in the CL and in the above-and lower-lying horizons and buried soils of the same age. Most of the mycological properties of the soils of ancient settlements are also typical of modern urban soils. Thus, the mycological properties of soils can be considered informative carriers of soil memory about ancient anthropogenic impacts.     

Quantitative variation as a tool for detecting human-induced impacts on genetic diversity

We propose quantitative genetic variation as a useful tool complementary to molecular variation in order to detect changes in biodiversity caused by different human-induced activities. We simulated a metapopulation setting under a number of realistic scenarios caused by anthropogenic activities (population isolation, reduced carrying capacity or reproductive rates, shifts in the local optima, and enhanced environmental variation or mutational rates). The effects on diversity of these scenarios were assessed for neutral variation estimated from molecular markers and for an additive quantitative trait that represents a typical morphological characteristic subject to stabilising selection promoting local adaptation to environmental conditions. The results show that monitoring quantitative genetic variation can be more informative than neutral variation to detect some human-induced environmental or genetic impacts on diversity, both at intra and interpopulation levels. We also compared the precision of diversity estimates obtained from molecular markers and quantitative traits. Under low migration rates and typical selection intensities for the quantitative trait, the precision of estimates can be substantially larger for a quantitative trait than for a single molecular marker. Thus, about 10-20 (2-4) independent markers are necessary for the precision of estimates of heterozygosity (population differentiation) from molecular markers to reach that of genetic variances (differentiation) from quantitative traits.     

土石混合工程堆积体土壤理化性状与物种多样性的响应

为了探讨喀斯特区土石混合工程堆积体植被恢复过程中物种多样性与土壤理化性状的互作关系,以不同恢复时段恢复时间(1,2,4,6 a)依坡倾倒型工程堆积体为研究对象,采用“空间代替时间”的研究方法,研究了不同恢复时间土壤理化性状和植物物种多样性的特征及相互之间的响应机制。结果表明:随恢复时间增加,土石混合堆积体台面和坡面植物种类呈现先上升后下降的趋势,且坡面植物种类(99种)多于台面(74种),植物群落逐渐由草本向草灌混交转变。台面和坡面的物种丰富度、多样性、优势度和均匀度指数随恢复年限恢复时间增加均表现为先增加后减小。随植被恢复时间增加,土壤理化性质得到不同程度的改善,其中土壤全氮(TN),全磷(TK),速效磷(AP)和有机质(SOM)含量显著增加,土壤养分含量呈上升趋势,坡面土壤理化性质优于台面。冗余分析(RDA)表明,土壤含水量(MC),容重(BD),TN,TK和速效钾(AK)在不同恢复时段恢复时间内对植物物种多样性有较大影响;钾素在较短的恢复时间内对物种多样性影响较大,氮素随恢复时间延长影响逐渐增加,MC和BD对台面物种多样性的影响大于坡面,而土壤养分因子对坡面影响较大。因此对土石混合堆积体进行植被恢复时,恢复前期采取添加覆盖物等措施减少水分流失的同时施用钾肥尽量保证植物存活,植物物种种类上选择既能保水保土又能与土壤微生物相互作用补充土壤中营养元素的豆科类植物。     

五台山森林群落中物种多样性对旅游干扰的生态响应

在对五台山森林植被进行分类的基础上,利用丰富度指数、均匀度指数和多样性指数,研究了不同森林群落中物种多样性对旅游干扰的生态响应。结果表明:(1)各项指数与群落类型有关,群落物种数量越多,其丰富度较大;群落结构越复杂,层次越分明,其多样性指数越大。同时,各项指数与群落发展的限制因素有关,干扰区群落多样性主要受旅游的影响,非干扰区群落多样性主要受海拔等自然条件的影响。(2)干扰区森林群落随着旅游影响的增大,除Simpson指数外,其它指数都呈现下降的趋势。非干扰区森林群落随着海拔高度的增加,除Simpson指数和Alatalo指数外,其它指数都呈下降的趋势。     

Forest management and wildlife in forested wetlands of the southern Appalachians

The southern Appalachian region contains a variety of forested wetland types. Among the more prevalent types are riparian and bottomland hardwood forests. In this paper we discuss the temporal and spatial changes in wildlife diversity and abundance often associated with forest management practices within bottomland and riparian forests. Common silvicultural practices within the southern Appalachians are diameter-limit cutting, clearcutting, single-tree selection, and group selection. These practices alter forest composition, structure, and spatial hetereogeneity, thereby changing the composition, abundance, and diversity of wildlife communities. They also can impact special habitat features such as snags, den trees, and dead and down woody material. The value of wetland forests as habitat also is affected by characteristics of adjacent habitats. More research is needed to fully understand the impacts of forest management in wetlands of the southern Appalachians.     

基于SSR标记的梨资源遗传多样性分析

本研究利用SSR标记技术对56份梨资源进行了遗传多样性分析。利用筛选出的6对SSR引物共扩增40条谱带,其中多态性位点38个,多态性位点比例为95%,每对引物产生有效等位基因6.3个。各位点期望杂合度H值在0.0354～0.491,平均为0.1964;有效等位基因Ne值在1.0367～1.9648,平均值为1.2958;香农指数I值平均值为0.3256,说明了供试梨材料的遗传多样性较低。利用SSR标记可将44个栽培品种区分开,但无法区分芽变和原种。根据SSR标记揭示的多态性,采用NTSYS-pc软件,以UPGMA法进行聚类分析,结果显示所检测的56份梨材料在相似系数0.71处可分为4组,其中中国的白梨、秋子梨和砂梨相互交错在一起,没有独自各自成组。     

Phylogeny of Vicia Subgenus Vicia (Fabaceae) Based on Analysis of RAPDs and RFLP of PCR-Amplified Chloroplast Genes

We report the results of two methods of DNA analysis to elucidate phylogenetic relationships among 29 Vicia subgen. Vicia species in comparison with two species of subgenus Vicilla sect. Vicilla. The methods employed were RAPD analysis of total genomic DNA and PCR-RFLP analysis of five chloroplast genes, rbcL, rpoB, 16S, psaA and trnK. The results of each method were similar and complementary, and support the current taxonomic systems of subsp. Vicia. According to RAPD and PCR-RFLP analysis the Narbonensis complex can be considered a well separated section, which may be related to section Vicia. Sections Vicia, Atossa and Wiggersia are separate, but closely related sections. Species of the section Hypechusa form a single monophyletic section, where V. lutea, V. anatolica and V. hyrcanica are quite remote from other species. Our results suggest that within the subgenus Vicia, V. faba is more closely related to V. bithynica and that these two species are most closely related to section Peregrinae. We found that PCR-RFLP of cp DNA provided more precise information concerning relationships between Vicia sections than RAPD analysis. However, RAPD analysis was more informative concerning diversity of closely related Vicia taxa, such as the variable groups, section Narbonensis and V. sativa aggregate.     

Moderate impacts of plant invasion and management regimes in coastal hind dune seed banks

Plant invaders may directly or indirectly affect ecosystem resilience through their impact on soil seed banks. The invaders, and the application of control measures, change seed bank dynamics by altering the number of seeds entering and leaving the seed bank. We tested the impact of bitou bush (Chrysanthemoides monilifera ssp. rotundata), on the seed bank. We examined seed banks in heavily-invaded, sparsely-invaded and managed dunes, where bitou bush biomass had been controlled. While management of bitou bush may have reduced the density of bitou bush seeds in the soil, it did not reduce the richness of other weed species. Native tree species richness was significantly higher in seed banks of sparsely-invaded than either heavily-invaded or managed sites, perhaps indicating a permanent shift in community structure following invasion. However, remaining indices of native seed bank diversity were similar across all invasion categories, indicating that seed banks of many native species were unaffected by both invasion and management. While examination of seed banks is informative in assessing past and potential community dynamics, low similarity between the standing vegetation and seed bank at all sites indicated that many hind dune species had other storage or regeneration modes and seed banks cannot be relied upon for comprehensive dune restoration.     

Features of forest litters in conjunction with ground cover in the forest ecosystems of Moscow oblast (based on the example of the Chashnikovo Educational-Experimental Soil-Ecological Center)

The stocks and structure of forest litters in a typical biogeocenosis in conjunction with the ecological and botanical characteristics of the soil layer have been studied, based on the example of the Chashnikovo Educational-Experimental Soil-Ecological Center, Moscow State University. The most informative characteristics of the soil layer include species diversity, the relative share of oligotrophic boreal and nitrophilous species, and the soil fertility index determined by the Ramensky ecological scale [20]. The total litter stock varies from 1500 to 6000 g/m² in coniferous forests and from 70 to 700 g/m² in small-leaved forests. The highest difference in stocks between the F and L horizons has been established for vegetation microcommunities with the maximum species diversity and highest share of nitrophils. The increase in the portion of welldecomposed fractions in the L piedmont from 5–7 to 27.6% leads to growth in the soil fertility index from 5–6 to 12–13.     

Highly polymorphic AFLP markers as a complementary tool to ITS sequences in assessing genetic diversity and phylogenetic relationships of sweetpotato (Ipomoea batatas (L.) Lam.) and its wild relatives

Comparative analyses of genetic diversity and phylogenetic relationshipsof sweetpotato (Ipomoea batatas (L.) Lam.) and its wildrelatives in Ipomoea series Batataswere conducted using amplified fragment length polymorphism (AFLP) and sequencedata from the internal transcribed spacer (ITS) region of the ribosomal DNA. LowITS divergence among thirteen species of ser. Batatasresulted in poorly resolved relationships. More variable AFLP characters werefound to be more efficient in characterizing genetic diversity and phylogeneticrelationships at both intra- and interspecific levels within ser.Batatas. Highly informative AFLP fingerprints of 36accessions representing 10 species of ser. Batatas weregenerated using only six primer combinations. Of the species examined,I. trifida was found to be the mostclosely related to I. batatas, whileI. ramosissima andI. umbraticola were the most distantlyrelated to I. batatas. The highlypolymorphic AFLP markers are a valuable tool in assessing genetic diversity andphylogenetic relationships of sweetpotato and its wild relatives.     

Changes in the properties of soils of Moscow forest parks under the impact of high recreation loads

The impact of off-road recreation loads with free moving of visitors across the area of forest parks is considered. This type of recreation loads exerts the most pronounced negative impact in soils. Quantitative estimates of changes in the morphological, physical, chemical, and biological properties of soils in Moscow parks Bitsevskii and Losinyi Ostrov under the impact of high recreation loads are given. Among the studied soil properties, the most significant changes take place in the soil structure, penetration resistance, and electrical conductivity. Quantitative data on the decrease in the number, biomass, and species diversity of soil mesofauna are also given.     

Cytoplasmic diversity of the cotton genus as revealed by chloroplast microsatellite markers

The diversity of chloroplast genomes has played an important role, as have those of nuclear and mitochondrial genomes, in the evolution of plants. The sequences of the chloroplast genome supply unsubstituted information for genome analysis. In order to understand the genetic differentiation and relationship of cotton species, we investigated the cytoplasmic diversity of chloroplast genomes in 41 Gossypium accessions with 75 chloroplast simple sequence repeat (cpSSR) markers. The markers were developed from reference sequences of the chloroplast genomes of G. hirsutum and G. barbadense and covered approximately 12.6 kb. Among the 75 markers, 50 were polymorphic, with polymorphism information content values ranging from 0.11 to 0.88. Analyses of the dataset demonstrated that single copy regions were much more informative than inverted repeat regions. The non-coding sequences were well differentiated among these species. For some common cpDNA haplotypes, the E-genome species that may be the oldest of the extant cotton species was deduced. The differentiation of A-genome species lagged behind that of AD-genome species. Neither G. herbaceum nor G. arboreum was the cytoplasmic donor of tetraploid species, strongly suggesting that AD genomes originated from an extinct ancestor of modern A-genome species. We speculate that the genetic differentiation of the chloroplast genome of each cotton species resulted from the dispersal of that species and its adaptations to local ecological conditions. These cpSSR markers provided valuable information to reveal the diversity and differentiation of cotton during evolution.     

Inter-Simple Sequence Repeat fingerprints to assess genetic diversity in Tunisian fig (Ficus carica L.) germplasm

The genetic diversity of 18 Tunisian fig cultivars was investigated at the DNA level using the Inter Simple Sequence Repeat (ISSR) associated with the Polymerase Chain Reaction (PCR). Using a set of primers, the most informative ones were selected that were characterized by an important Resolving power value of 29.6. A total of 47 discernible fragments were scored from samples, with a mean of 11.7 fragments per primer. The 90.4% of sample that were polymorphic were scored as molecular markers to examine the Tunisian fig germplasm polymorphism at DNA level. A large genetic diversity as related to ISSR patterns was found within the local Tunisian fig germplasm. An UPGMA dendrogram exhibits the unstructured variability in this crop. Moreover, the principal component analysis shows that the observed diversity was typically continuous. Our data provide a large number of ISSR markers that are useful in the fingerprinting of Ficus carica L. cultivars, and in the understanding of the genetic relationships among these accessions.