Pattern diversity analysis of a clearing in a Quercus cerris wood

Linear transects were used to examine the spatial structure of the vegetation in a clearing in a Quercus cerris wood in Central Italy. A grassland-margin-shrubland-woodland gradient was identified.Multivariate classification and ordination methods and pattern diversity analysis were used to detect both floristic variation and spatial organization. One of the transects shows a clear gradient of variation as a function of space, crossing the floristically and structurally most heterogeneous part of the clearing. For the detailed analysis of this transect a sectorization is achieved. Each sector is characterized according to its floristic types and to the internal spatial organization.The pieces of information derived from the different analyses were concordant. In particular, the validity of the floristic types in the qualification of the different forms of spatial organization is confirmed.     

Identifying habitat types in a disturbed area of the forest-steppe ecotone of Patagonia

We surveyed an old ranch (22,000 ha) in the eastern catchment of lake Nahuel Huapi (Argentina), representing both landscape and historical use patterns of the forest-steppe ecotone in the Andes foothills. The objective was to describe plant-environment relations and to develop a procedure to classify habitat types for conservation aims. Floristic and landscape variables were recorded in 72 upland sites. Vegetation types were classified with Two-way indicator Species Analysis and environmental gradients detected with Detrended Canonical Correspondence Analysis. Vegetation types were tested for environmental homogeneity with Discriminant Analysis. A key to classify habitat types was built out from the classification functions obtained by DA analysis. Floristic classification resulted in 7 steppe types and 4 shrubland/woodland types. Vegetation samples were placed along two main gradients, one related to topography and the other to the type of substrate. Steppe types occur in all positions of the topographic gradient forming a temperature-soil moisture continuum, but only (except one of them) on accumulated substrates. Islands of woody types are confined to relatively warm positions of the topographic gradient and to deflated, rocky substrates. This distribution pattern would be caused by frost sensibility of forest species, and by the different strategies of water capture of woody and herbaceous plants. Three pairs of plant assemblages were not discriminated, allowing classification of 8 habitat types out of the 11 communities. Undiscriminated communities (3 pairs) and misclassified samples (29%) were discussed as the result of disturbances.     

The folding type of a protein is relevant to the amino acid composition

The folding types of 135 proteins, the three-dimensional structures of which are known, were analyzed in terms of the amino acid composition. The amino acid composition of a protein was expressed as a point in a multidimensional space spanned with 20 axes, on which the corresponding contents of 20 amino acids in the protein were represented. The distribution pattern of proteins in this composition space was examined in relation to five folding types, alpha, beta, alpha/beta, alpha + beta, and irregular type. The results show that amino acid compositions of the alpha, beta, and alpha/beta types are located in different regions in the composition space, thus allowing distinct separation of proteins depending on the folding types. The points representing proteins of the alpha + beta and irregular types, however, are widely scattered in the space, and the existing regions overlap with those of the other folding types. A simple method of utilizing the "distance" in the space was found to be convenient for classification of proteins into the five folding types. The assignment of the folding type with this method gave an accuracy of 70% in the coincidence with the experimental data.     

神农架川金丝猴投食群的社会行为谱

为探讨人工投食条件下川金丝猴的社会行为类型,2007年1月-2008年10月,采用行为取样法和全事件记录法对湖北神农架自然保护区投食猴群的社会行为进行观察。确定投食群有45种典型社会行为,其中打架、抢食、抱腰、吻背、爬伏、邀配与以往对笼养和野生川金丝猴的研究有差别。     

Colony Structure of a Consortium of Nitrifying Bacteria

Colonies produced by a consortium of nitrifying bacteria were studied using light and electron microscopy. The colonies were obtained by direct plating of inoculum from a two-stage nonsterile chemostat fermentor and by repeatedly passing the microbial community of the fermentor through selective media containing ammonium or nitrite. The colonies studied can be characterized by a specific combination of six types of cells differing in their ultrastructure and spatial location within the colony. The types of cells occurring within a given colony were found to depend on the nitrogen compound present in the medium. As a result of our study, morphological features of colonial bacterial communities were identified. The proposed approach can be viewed as a method to describe microbial associations and communities.     

Evidence for a Multiplicity of Capsular Types Among Staphylococcus aureus Strains

The Smith diffuse variant and the wound mucoid strain of Staphylococcus aureus were shown to exhibit serologically distinct capsules. The Welwood and K-6 strains of S. aureus were tested to determine their capsular types. Both Welwood and K-6 were found to be representative of the Smith capsular type. An additional 13 isolates of S. aureus from mice were tested. Gel double-diffusion tests and immunoelectrophoresis of staphylococcal antigens disclosed the possible existence of at least two additional capsular types. Passive hemagglutination tests carried out with cells sensitized with 1 mg of antigen per ml showed a multiplicity of cross-reacting antigens. However, cells sensitized either with 0.1 or 0.05 mg of antigen per ml and reacted with antisera absorbed with 10 or 1 mug/ml showed the presence of a specific antigen in each strain of S. aureus. Corroborative evidence for a multiplicity of capsular types was obtained by the specific capsular reaction. At least four capsular types of S. aureus were found. The prototypic strains for these antigens are the RLM or wound strain, the Smith diffuse strain, and mouse strains designated 36T and 43R. We propose to designate these types 1, 2, 3, and 4, respectively.     

In search of a hydrological explanation for vegetation changes along a fen gradient in the Biebrza Upper Basin (Poland)

The understanding of succession from rich fen to poorer fen types requires knowledge of changes in hydrology, water composition, peat chemistry and peat accumulation in the successional process. Water flow patterns, water levels and water chemistry, mineralisation rates and nutrient concentrations in above-ground vegetation were studied along a extreme-rich fen-moderate-rich fen gradient at Biebrza (Poland). The extreme-rich fen was a temporary groundwater discharge area, while in the moderate-rich fen groundwater flows laterally towards the river. The moderate-rich fen has a rainwater lens in spring and significant lower concentrations of calcium and higher concentrations of phosphate in the surface water. Mineralisation rates for N, P and K were higher in the moderate-rich fen. Phosphorus concentrations in plant material of the moderate-rich fen were higher than in the extreme-rich fen, but concentrations of N and K in plant material did not differ between both fen types. Water level dynamics and macro-remains of superficial peat deposits were similar in both fen types.We concluded that the differences observed in the moderate-rich and the extreme-rich fens were caused by subtile differences in the proportion of water sources at the peat surface (rainwater and calcareous groundwater, respectively). Development of an extreme-rich fen into a moderate-rich fen was ascribed to recent changes in river hydrology possibly associated with a change in management practices. The observed differences in P-availability between the fen types did not result in significantly different biomass. Moreover, biomass production in both fen types was primarily N-limited although P-availability was restricted too in the extreme-rich fen. Aulacomnium palustre, the dominant moss in the moderate-rich fen, might be favoured in competition because of its broad nutrient tolerance and its quick establishment after disturbance. It might outcompete low productive rich fen species which were shown to be N-limited in both fens. We present a conceptual model of successional pathways of rich fen vegetation in the Biebrza region.     

Colony structure of a consortium of nitrogen-fixing bacteria

Colonies produced by a consortium of nitrifying bacteria were studied using light and electron microscopy. The colonies were obtained by direct plating of inoculum from a two-stage nonsterile chemostat fermentor and by repeatedly passing the microbial community of the fermentor through selective media containing ammonium or nitrite. The colonies studied can be characterized by a specific combination of six types of cells differing in their ultrastructure and spatial location within the colony. The types of cells occurring within a given colony were found to depend on the nitrogen compound present in the medium. As a result of our study, morphological features of colonial bacterial communities were preliminarily identified. The proposed approach can be viewed as a method to describe microbial associations and communities.     

Pollen deposition in a small closed drainage basin lake

A moss cushion and fifteen lake bottom samples from a small volcanic crater lake in southeastern South Australia were examined for pollen. The distribution of pollen types is analysed in relation to the distance from source areas of Eucalyptus woodland and Pinus radiata plantations, and in relation to water depth in the lake.Most taxa were only detectable in small quantities within a few metres of the source plants. The decline in these local pollen types led to a relative increase in regional pollen types in the centre of the lake. This is a problem which makes interpretation of the extent of the redeposition factor difficult for some taxa. The redeposition factor was small for extralocal taxa including Pinus radiata and Eucalyptus spp. as their relative frequencies declined noticeably toward the centre of the lake. Regional types included Casuarina stricta, Chenopodiaceae, Polygonaceae and Poaceae pollen. Aquatic pollen was derived within the lake and does not contribute to the regional pollen rain. The majority of these taxa have highest values near the source plants but were also deposited elsewhere in the lake. The exceptions to this were Triglochin and Typha angustifolin pollen; the former showed a distribution pattern which had little relation to the occurrence of the plant while the latter had highest relative frequencies away from the source plants. The implications in relation to water depth interpretation from fossil pollen profiles are discussed.     

Occurrence of pollen and spores in relation to present-day vegetation in a Dutch heathland area

Abstract. Pollen, spores and fungal remains in moss cushions along a transect, traversing a Betula-Quercus forest and a surrounding heathland, were analysed in order to study the relation between present-day vegetation and recent pollen deposition. Pollen and spores are divided into local types from plant species encountered along the transect and regional types, not present along the transect. Relative percentages and absolute concentration of the palynomorphs were estimated. Radiocaesium activity in the moss was measured to assess the minimal duration of palynomorph accumulation (i.e. the age of the moss samples). The absence of simultaneous trends in the regional pollen types indicates that the samples do not have major differences in age. The moss represents the later stages in the heath mosaic cycle. This is supported by the radiocaesium content of the moss. Thus, in this case the concentration values of regional pollen approach deposition values. The values of the local pollen types calculated on such a rather constant regional pollen flux is considered to represent real differences in the local deposition. The local pollen types can be arranged topographically into five groups characteristic of the local vegetation types and their ecotones. The arrangement of the curves of types from phyco-, zoo-, and myco-coenoses suggests their possible origin, either locally from the heath area or from the Betula-Quercus forest, or regionally from elsewhere. Analyses and topographical arrangement of the curves of unknown types contribute in this way to their identification and their possible source of origin.     

Trajectory analysis of Chinese vegetation types in a multidimensional climatic space

Abstract. The concept of trajectory of a vegetation type is used as a tool to study the position of vegetation types in a multidimensional climatic space. This space was obtained by Principal Component Analysis based on climatic data - based on monthly means. The positions of the main vegetation types distinguished in China were plotted in the climatic space and trajectory lengths and shapes of the types were compared. Three main groups were found, which correspond to: (1) cold and temperate, (2) alpine and mountain, and (3) subtropical and tropical conditions. Within each main category sub-categories were distinguished on the basis of trajectory length and direction. In total, seven trajectory shapes were defined. Based on the correlation between climatic variables and PCA-axes temperature is suggested to be the overriding factor in determining the trajectory shape. But, trajectories can also be affected by the combination of other climatic variables.     

Molecular epidemiological analysis of bloodstream isolates of Candida albicans from a university hospital over a five-year period

We assessed the genetic relations and epidemiological links among bloodstream isolates of Candida albicans, which were obtained from a university hospital over a period of five years. The 54 bloodstream isolates from the 38 patients yielded 14 different karyotypes, 29 different patterns after digestion with SfiI (REAG-S), and 31 different patterns after digestion with BssHII (REAG-B) when analyzed using three different pulsed-field gel electrophoresis (PFGE) typing methods. In 11 patients with serial bloodstream isolates, all strains from each patient had the same PFGE pattern. The dendrograms for all of the strains revealed that the distribution of similarity values ranged from 0.70 to 1.0 in the REAG-S patterns, and from 0.35 to 1.0 in the REAG-B patterns. Overall, the combination of the three different PFGE methods identified 31 distinct types, reflecting the results obtained using the REAG-B alone different. different Five PFGE types were shared among 22 isolates from 12 patients. These types of strains were more frequently associated with central venous catheter-related fungemia than the other 26 type strains (92% versus 31%; P < 0.005). Of five PFGE types, four isolates were determined to be epidemiologically related: each of these types was primarily from two or three patients who had been hospitalized concurrently within the same intensive care unit. Our results suggest that the REAG-B constitutes perhaps the most useful PFGE method for investigating C. albicans candidemia and also shows that a relatively high proportion of C. albicans candidemia may be associated with exogenous acquisition of clonal strains.     

Trophic associations of a dung beetle assemblage (Scarabaeidae: Scarabaeinae) in a woodland savanna of Botswana

Species richness and abundance of dung beetles were assessed across a range of bait types that acted as surrogates for the food resources available in Chobe National Park, Botswana. These bait types were comprised of the dung of pig (omnivore), cattle (ruminant herbivore dropping fine-fiberd pads), sheep (pellet-dropping ruminant herbivore), and elephant (monogastric, nonruminant herbivore producing coarse-fibered droppings), and chicken livers (carrion). Species richness was similar between traps baited with pig, cattle, and elephant dung but was relatively lower in those baited with sheep dung and carrion. In traps baited with pig dung, abundance was relatively greater than in all other bait types. A cluster analysis of species abundance distributions for the 30 most abundant species identified four different patterns of bait type association at a 60% level of similarity. All but 1 of the 15 species in cluster A were attracted primarily to the dung of omnivores and pad-dropping ruminant herbivores (pig and cattle). All seven species of cluster B were attracted primarily to coarse-fibered, nonruminant herbivore dung (elephant). All four species of cluster C were primarily carrion and pig dung associated, whereas all four species of cluster D were carrion specialists. In conclusion, the most abundant species were attracted to all bait types, but most species were largely specialized to different dung types or carrion, with dung attracting the majority of the fauna in terms of both species richness and abundance.     

Satellite imagery as a tool for monitoring species diversity: an assessment

1. A landscape of 5 × 5·5 km in the Karnataka region of the Western Ghats of India was mapped into seven landscape element types, using field identification of types as well as supervised and unsupervised classification of satellite imagery.
2. Plant communities distributed in these landscape element types were surveyed in the field using 246 quadrats of 10 × 10 m, in order to assess whether these types could be distinguished in terms of species composition. All angiosperms excluding grasses, which could not be identified accurately in the field, were recorded for this purpose.
3. Landscape element types identified in the field harboured significantly distinctive sets of species of flowering plants, and were also by and large distinctive in terms of their species richness.
4. Landscape element types could be identified accurately on the basis of supervised classification: the types thus demarcated harboured distinctive sets of flowering plants.
5. Landscape element types coupled to satellite imagery could then be used to organize a programme of monitoring biodiversity.
6. Unsupervised classification of satellite imagery did not permit classification of landscape element types with a high enough level of accuracy. In consequence, the demarcated landscape element types did not harbour significantly distinctive sets of species of flowering plants. Unsupervised classification is therefore not appropriate in a programme of monitoring biodiversity.     

Carbon dioxide exchange fluxes of a boreal peatland over a complete growing season, Komi Republic, NW Russia

The carbon pool of peatlands has been considered as potentially unstable in a changing climate. This study is the first presenting carbon dioxide (CO₂) net ecosystem exchange, CO₂ efflux due to ecosystem respiration and CO₂ uptake by gross primary production over a complete growing season for different microforms of a boreal peatland in Russia (61°56′N, 50°13′E). CO₂ fluxes were measured using the closed chamber technique from the 25th April in the period of snow melt until the end of the vegetation period and the first frost on the 20th October 2008 at seven different microform types: minerogenous and ombrogenous hollows, lawns and hummocks, respectively, and Carex lawns situated in a transition zone between minerogenous and ombrogenous mire parts. The total number of chamber flux measurements was 5,517. Ombrogenous hummocks and lawns were sources of CO₂ over the investigation period whereas hollows and minerogenous lawns were CO₂ sinks. Some plots of Carex lawns and minerogenous hummocks were sinks while other plots of these microform types were sources. The CO₂ fluxes were characterised by large variability not only between the microform types but also within the respective microform types. Of all microform types, the Carex, ombrogenous, and minerogenous lawns showed the highest variability in CO₂ fluxes, which is probably related to a stronger within-microform heterogeneity in vegetation composition and coverage as well as in the water table level. Air temperature was one of the dominant controls on the CO₂ flux dynamics. Water table and green area index were found to have strong influence on CO₂ fluxes both within different patches of the same microform type as well as between different microforms.     

Status of airborne spores and pollen in a coir factory in Kerala,India

The prevalence of airborne fungal spores and pollen grains in the indoor and outdoor environments of a coir factory in Thiruvananthapuram district of Kerala state, India was studied using the Burkard Personal Sampler and the Andersen 2-stage Sampler for 2 years (September 1997 to August 1999). The concentration of pollen grains was remarkably lower than that of fungal spores (ratio of 1:28). There was no large difference in the concentrations and types of fungal spores between the indoor and outdoor environments, with 26 spore types found to be present indoors and 27 types outdoors; of these, 22 were common to both the environments. Aspergillus/Penicillium, Cladosporium, ‘other basidiospores’ and ascospores were the dominant spore types. The total spore concentration was highest in February and lowest in September, and it was significantly higher in 1998–1999 than in 1997–1998. Twenty viable colony-forming types were isolated from inside the coir factory. The most dominant viable fungi isolated were Penicillium citrinum, Aspergillus flavus and Aspergillus niger. The total pollen concentration was higher in the outdoor environment of the coir factory than indoors, with 15 and 17 pollen types, respectively. Grass and Cocos nucifera pollen types were dominant. The dominant spore and pollen types trapped in the two environments of the coir factory are reportedly allergenic and, consequently, workers are at risk of catching respiratory/allergic diseases.