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Because bees fly around, visit flowers and chase mates, we conclude intuitively that they see things as we do. But their vision is unexpectedly different, so we say it is anti-intuitive. Detailed tests have demonstrated separate detectors for modulation of blue and green receptors, edge orientation (green only), and areas of black. The edge detectors are about 3° across, independent, and not re-assembled to make lines, shapes or textures. Instead, the detectors of each type are summed quantitatively to form cues in each local region with an order of preference for learning the cues. Trained bees remember the positions of the total modulation (preferred), the average edge orientation, areas of black or colour, and positions of hubs of radial and circular edges in each local region, but not the original responses, so the pattern is lost. When presented with a yellow spot on a blue background with no UV reflected, the preferred cue is not the colour, but a measure of the modulation detected by the green and separately by the blue receptors.
The main aim of this study was to evaluate the appropriateness of using different diversity indices for conservation purposes in arid environments. The study was done on Mt Serbal as a case study representing mountainous arid areas. Mt Serbal is one of the richest and most diverse areas in Egypt. It was sampled by 97 stands representing different vegetation cover, land-forms and habitats. Species density and environmental factors (including altitude, slope, soil texture, hygroscopic moisture, water holding capacity, pH, EC, and soil organic matter content) were recorded or measured in each stand. The results reveal that Mt Serbal is characterised by a high diversity of plant species and the most diverse area is Shaq Sha’rany. The study recommends Margalef and species richness as the most suitable to measure the diversity at different localities, land-forms, and vegetation groups. It emphasises on the necessity of reporting on species richness in any conservational study. Meanwhile, indices that are excessively sensitive to change in sample size, gear, or handling procedures should be avoided.
The study area is the peaty bed of Nyíres-tó mire which is situated in the northeastern Alföld on the Bereg Plain. For this paper we used a digital photo interpretation method with which we reconstructed the former vegetation from black and white aerial photos, and made chronosequence of vegetation maps. The image segmentation method dissolves the photo into different objects (segments) by spectral and textural parameters. The segments consist of similar pixels, representing a unique ground object. We made the segmentation with the Definiens Inc. eCognition software. The stability of the mire was calculated with GRID-files. The historical vegetation maps show, that after many arid years, the tree or shrub dominant associations increased until the eighties. Later, the sufficient precipitation and the artificial flooding stabilised the tree covering. The analysis of GRID-files shown, that 45.77% of the pixels get code 1 (stable), 44.32% get code 2 (slightly changeable) and only 9.91% get code 3 (changeable). It means that almost half of the mire’s vegetation is the same as in 1952.
At first, a natural widespread mass growth of Zygnema stellinum was recorded in El-Hikstep new city (Egypt). The mechanical, physical and chemical characters of the wet soil in El-Hikstep new city where filaments of Zygnema were collected; the natural city soil where there is no growth and soil from ditches after the death of the filamentous growth were studied and analysed. The current study revealed that pH, E.C., MgSO4 and NaCl, available P and N were the most controlling factors those enhance the green algal mats growth of Zygnema stellinum in this site. The physico-chemical analysis of soil sample after the death of Zygnema was characterised by a reduction in the values of pH, E.C., change in soil texture from sand in city soil to loamy-sand for two other soil samples. These were associated with increase in the values of organic matter, organic carbon, phosphorus, nitrogen and Fe comparing with physico-chemical analysis of the city soil sample. These may emphasise that the growth and death of green algal mats of Zygnema in soil probably have reclaimative properties in soil. Meanwhile, cultivation test revealed successfully growth of Zygnema stellinum in city soil extract medium followed by the city soil extract nutritive media. Whereas the growth of Zygnema stellinum in Beijerinck and Allen media doesn’t well.
A cell-grid method was used to survey seasonal changes in four herbaceous communities of a wooded pasture. Permanent plots consisted in 1-m2 grids subdivided into 100 cells of 1 dm2. In each cell of each plot and every month from May to September, we estimated dominance, and grazing occurrence of all species. Plant communities included an eutrophic grazed meadow, a temporary refused meadow, an underwood herb community and an oligotrophic lawn. Our results showed that seasonal changes in species composition were very strong and scale-dependent. Changes at plot scale were mainly driven by a seasonal shift. Changes at cell scale suggested high small-scale dynamics of species. Despite high changes at cell scale, the structure of the community did not change and local species richness did not show any trend. We found no correlation between the turnover at cell scale and cattle activity. We conclude that dynamics and internal species turnover of the community at fine scale and short time seem more driven by internal characteristics of the community than by disturbances induced by cattle. Furthermore, at seasonal scale, plant communities may be stable in their structure despite fluctuations in their texture.
This study profiled soils over a land degradation gradient to obtain formulae as integrative measures for describing the gradient as a result of deforestation in Thailand. We applied antibiotic resistance most-probable-number profiling to the soil bacterial communities, and then described the gradient. Soil samples were collected on the gradient represented by dry evergreen forest (the original vegetation), dry deciduous forest (moderately disturbed) and bare ground (the most degraded) in February (dry season), March (shortly after temporal precipitation) and June (rainy season) 2001. In the period of this study, the degradation was consistently shown as soil conditions like sandy texture, high bulk density, lower pH, high exchangeable acidity, poor mineral and organic nutrients and dryness. Soil fertility index and soil evaluation factor, as the integrative measures of the intensity of land degradation, were described by scores on the first or the second principal component derived from the soil bacterial community profiles for each sampling time (R>0.457, p<0.043) and by scores on the third and fourth principal components for the overall data set (R>0.501, p<0.001), suggesting great dry to moist seasonal effects. Further, the changes had significant relationships with gradients of soil moisture content, acidity and/or soil nitrogen content. The data sets on the soil bacterial community profiles had more complicated data structures than the physicochemical data sets, suggesting effects of the physicochemical changes on the soil bacterial community. The differences between the bacterial and the physicochemical aspects suggest that it is advantageous to observe multiple aspects of soil quality when describing a soil-related gradient of interest.
Birdseye primrose (Primula farinosa subsp. alpigena) is a strictly protected plant species of the Hungarian flora. Natural occurrences of the species are known from two fen meadows situated in a tectonic depression accompanying Lake Balaton. The restoration and management of recipient vegetation have a great importance because of the wide range fluctuation in number of individuals of the species for several years. In 2001 coenological behaviour was examined in classical and meso scale. Field data were collected by modified Zürich-Montpellier method and 1 m × 1 m quadrats as transects marked by environmental gradients with cover estimation by eye collecting presence-absence and quantitative data. Examining the classical and transect quadrats ecological indication, preferences and significance between species and habitats were revealed focusing on Birdseye primrose. In addition 8 soil parameters were analysed in Primula rich and Primula free sites of the habitats. The aim of our investigation was to broaden the knowledge about the biotic and abiotic habitat preferences of Birdseye primrose. According to our results not only the textural features (e.g. species composition, abundance) are insufficiant to save this species from extinction but the pattern and physiognomy of vegetation have more significance. The tussock-fen window complex provides prominent situation with its nudum surfaces offering favourable abiotic conditions and low competition. The effects of other characteristics of preferential sites (e.g. gap size, litter or moss cover) in micro scale are substantial in all probability. With this knowledge restoration and managing plan were executed focusing on two aspects: the maintenance of population size via directed seed dispersion and plantation and controlling of biotic as well as abiotic factors in the natural habitats.
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A recent floristic and environmental survey was undertaken on the roadside verges along the main highway between El Arish and Rafah (31° 10'N, 33° 48'E and 31° 17'N, 34° 15'E) that extend for about 45 km on the northeastern Mediterranean coast of Sinai (Egypt). 63 stands were studied at 700-m intervals to represent the variation of vegetation, and to compile the floristic composition of the study area. Four main landform zones were distinguished (from the seashore inwards) and run parallel to the roadway: (A) coastal plain, (B) saline depressions, (C) sand plains and (D) sand dunes. There is a gradual increase in the total number of recorded species in the recognized landform units. Application of TWINSPAN analysis yielded 18 vegetation groups (VG) that comprised 7 main vegetation types (VT). These vegetation types were (I) Artemisia monosperma in the sand dunes, (II) Artemisia monosperma-Echinops spinosus in the sand plains, coastal plain and sand dunes, (III) Cyperus capitatus-Ammophila arenaria in the sand dunes, (IV) Ammophila arenaria-Pancratium maritimum in the coastal plain, (V) Zygophyllum album, (VI) Arthrocnemum macrostachyum and (VII) Arthrocnemum macrostachyum-Zygophyllum album in the saline depressions. Ordination techniques of Detrended Correspondence Analysis (DCA) and Canonical Correspondence Analysis (CCA) were used to examine the relationship between the roadside vegetation and the 8 studied environmental variables: total soluble salts (TSS), pH, calcium carbonate (CaCO_), sand, fine fractions (silt and clay), distance from the seashore (DFS), landform units (LF) and altitude (Alt). Both ordination techniques indicated that soil salinity, calcareous sediments, soil texture, landform, altitude and distance from seashore were the most important factors for the distribution of the vegetation pattern along the road verges in the study area. These gradients were related closely to the first three CCA axes, and accounted for 72.4% of the species relationship among the stands. Low species richness in the vegetation types of the coastal plain and saline depressions may be related to their high soil salinity, while the high species diversity and the highest share of alien weeds of vegetation types characterized the sand dunes may be related to the high disturbance of their substrates as a result of agriculture practising, farming processes and other excessive human disturbances.
well known and has existed since ancient times: the making of sourdough. This method has some advantageous effects, like flavour, aroma, texture development and better digestion of the products due to the fermentation. More research proved that this
