Epiphytic vegetation on pollarded trunks of Fraxinus excelsior in four different habitats at Grinde,Leikanger, western Norway

The epiphytic vegetation on 24 pollarded trees of Fraxinus excelsior at the farm Grinde, Leikanger, western Norway was investigated. Each trunk was divided into a basal zone, a middle zone and a top zone. In each zone the four different aspects were analysed (12 sampling units from each trunk). Within a total of 276 sampling units, 162 taxa were recorded (99 lichens, 56 bryophytes, 7 vascular plants). The trunks were covered mainly by an old, thick and occasionally swollen bark, but decaying wood did not occur. Their habitats were different, and each trunk was classified into one of four categories: open meadow, wooded hay meadow, deciduous wood, and spruce plantation. A climate station was established in each habitat to measure important parameters. The floristic and environmental data were analysed by canonical correspondence analysis (CCA). The floristic data were classified into eight TWINSPAN groups that have been taken into account in the CCA diagrams. At Grinde all the pollarded trunks grew under fairly homogeneous conditions during a more extensive agricultural period until about 1962. The deciduous wood developed by tree colonization on old meadows and wooded hay meadows, whilst spruce has been planted in a small part of the area. Floristic differences in the epiphytic vegetation between the four different habitats were found, which suggests that changes in the vegetation have developed during the last two or three decades. The spruce plantation was the most shady habitat having a very sparse epiphytic vegetation, mainly remnants from vegetation established during more open area conditions.     

Multivariate analysis of vegetational changes in permanent woodland plots with different sewage sludge treatments

Vegetation data from an experiment on the impact of sewage sludge on woodland vegetation dynamics are analysed by ordination to examine the reaction of a forest community to sludge disturbance. Two different kinds of vegetational response are discussed in relation to horizontal patchiness of vegetation. It is suggested that the species-poor component of the vegetation mosaic observed reveals quicker recovery from sludge disturbance than the species-rich component, which is characterized by a more complicated network of interspecific relations. A high correlation between plot-scores on the first ordination axis and sludge dose is found, indicating that in the altered community the main vegetational gradient reflects the intensity of disturbance. An attempt is made to interpret the main gradients of vegetational variation in terms of ecological indicator values of species. It is concluded that the modified competitive ability of species in a changed environment plays the most important role in building up a new community structure.     

Salt marsh vegetation of the Western Mediterranean desert of Egypt

The extensive salt marshes in the plains and depressions of the western Mediterranean desert of Egypt were classified into three habitat types: A with shallow water table and high salinity, B with relatively deep water table and high salinity, and C transitional habitats in which salinity and water table are no controlling factors. Fourteen vegetation types were distinguished, each dominated by one or two species.The dominating life forms are chamaephytes in sites of high salinity, and therophytes in sites of low salinity. Spatial and temporal variations in the standing crop biomass were pronounced. The accumulation of material started during spring and reached a maximum in autumn, when photosynthetic activity was maintained to account for transpiration losses.There was a general trend of increasing salinity and concentration of different ions from habitat type A to habitat type C through habitat type B. The periodical variation in the water table was insignificant, while a significant drop in salinity and the concentration of different ions was detected in spring, which was attributed to the diluting effect of rain water during that season.Most species exhibited clear distribution patterns and their a bundance varied significantly along gradients of different factors. Simple correlations between the compositional gradients or the distributional behaviour of species and salinity or the concentration of individual ions were generally low, while correlations with combinations of ions in the form of ratios (notably sodium and potassium adsorption ratos) were higher.During the early stages of succession the building up of soil and the decrease in salinity are the most important factors while at more advanced stages, soil texture and calcium carbonate content become more decisive.Nomenclature follows Täckholm (1974)     

Soil seed bank in different habitats of the Eastern Desert of Egypt

The floristic composition and species diversity of the germinable soil seed bank were studied in three different habitats (desert salinized land, desert wadi, and reclaimed land) in the Eastern Desert of Egypt. Moreover, the degree of similarity between the seed bank and the above-ground vegetation was determined. The seed bank was studied in 40 stands representing the three habitats. Ten soil samples (each 25 × 20 cm and 5 cm depth) were randomly taken per stand. The seed bank was investigated by the seedling emergence method. Some 61 species belonging to 21 families and 54 genera were identified in the germinable seed bank. The recorded species include 43 annuals and 18 perennials. Ordination of stands by Detrended Correspondence Analysis (DCA) indicates that the stands of the three habitats are markedly distinguishable and show a clear pattern of segregation on the ordination planes. This indicates variations in the species composition among habitats. The results also demonstrate significant associations between the floristic composition of the seed bank and edaphic factors such as CaCO₃, electrical conductivity, organic carbon and soil texture. The reclaimed land has the highest values of species richness, Shannon-index of diversity and the density of the germinable seed bank followed by the habitats of desert wadi and desert salinized land. Motyka’s similarity index between the seed bank and the above-ground vegetation is significantly higher in reclaimed land (75.1%) compared to desert wadi (38.4%) and desert salinized land (36.5%).     

Phytosociological and environmental gradients in a sector of the Western Desert of Egypt

Summary The climatic and physiographic features of the Western Desert of Egypt vary gradually from the Mediterranean coast inland. The present study provides an analysis of the gradients exhibited by these environmental variations and their relationships with vegetational gradients and the phytosociological behaviour of species in a sector along the Cairo-Alexandria desert road. The multivariate analyses of the vegetation lead to the recognition of six interrelated vegetational groupings which were distributed along a climatic gradient of increasing aridity, and an edaphic gradient of increasing sandiness and decreasing salinity and level of total phosphorus. These groupings were distinguished into three sets: a set ofConvolvulus-Helianthemum-Artemisia, andHelianthemum-Echiochilon, a set ofAnabasis, andSalsola-Anabasis, and a set ofAsphodelus-Noaea andThymelaea-Anabasis-Noaea groupings. The first set occupies the more arid end of the climatic gradient and the end of the coarse texture, low salinity and low levels of total phosphorus of the edaphic gradient. The second set occupies the opposite end of the edaphic gradient and the middle position of the climatic gradient and the middle position of the climatic gradient, and the third, the middle position of the edaphic gradient and the less arid end of the climatic gradient. Taxonomic nomenclature is according to T?ckholm (1974). The multivariate analyses were carried out using a Burroughs B6700 at the Computer Center of Utah State University, and supported by the U.S. Desert Biome. The authors are indebted to W. Valentine, H. C. Romesburg and K. Marshall for their assistance with data processing.     

Cluster analysis of recent benthic foraminifera from the northwestern Mediterranean coast of Egypt

A suite of 74 surface sediment samples, collected from two areas along the Egyptian Mediterranean coast (the Western Harbor of Alexandria and its environs, and the area comprising the Gulf of Kanayis and the Abu Hashafa Bay), have been examined for their benthic foraminiferal faunas. A total of 82 species were identified. Census data were obtained for different species in each sample and the statistically significant fractional abundances values (≥5%) were analyzed using a Q-mode cluster analysis. Samples were segregated into four clusters, each having its peculiar benthic faunal assemblage (biotope), reflecting particular environmental conditions. These clusters are: (1) the Ammonia beccarii forma tepida Biotope, found in samples located in areas with waters of low energy, characterizing semi-closed basin conditions, with muddy or sandy mud bottom sediments (Harbor Proper); (2) the Quinqueloculina spp. Biotope, found in samples collected from depths bathed by turbid inner shelf conditions with some fresh water inflow and sandy bottom sediments (Harbor’s environs); (3) the Peneroplis-Amphistegina Biotope, found in samples collected from depths characterizing marine shelf environments with calcareous algae, and medium to very coarse calcareous sands (the Gulf of Kanayis and the Abu Hashafa Bay); (4) the Triloculina trigonula-Adelosina laevigata Biotope was represented by only one sample (at the far eastern part of the Gulf of Kanayis), collected from a site exhibiting very restricted environmental conditions. The study suggests that nutrients, turbidity, light intensity, type of substrate, and salinity are the main ecological factors controllingthe distribution of benthic foraminifera.     

The use of climatic parameters and indices in vegetation distribution. A case study in the Spanish Sistema Central

In this study, over 100 phytoclimatic indices and other climatic parameters were calculated using the climatic data from 260 meteorological stations in a Mediterranean territory located in the centre of the Iberian Peninsula. The nature of these indices was very different; some of them expressed general climatic features (e.g. continentality), while others were formulated for different Mediterranean territories and included particular limits of those indices that expressed differences in vegetation distribution. We wanted to know whether all of these indices were able to explain changes in vegetation on a spatial scale, and whether their boundaries worked similarly to the original territory. As they were so numerous, we investigated whether any of them were redundant. To relate vegetation to climate parameters we preferred to use its hierarchical nature, in discrete units (characterized by one or more dominant or co-dominant species), although it is known to vary continuously. These units give clearer results in this kind of phytoclimatic study. We have therefore used the main communities that represent natural potential vegetation. Multivariate and estimative analyses were used as statistical methods. The classification showed different levels of correlation among climatic parameters, but all of them were over 0.5. One hundred and eleven parameters were grouped into five larger groups: temperature (T), annual pluviothermic indices (PTY), summer pluviothermic indices (SPT), winter potential evapotranspiration (WPET) and thermal continentality indices (K). The remaining parameters showed low correlations with these five groups; some of them revealed obvious spatial changes in vegetation, such as summer hydric parameters that were zero in most vegetation types but not in high mountain vegetation. Others showed no clear results. For example, the Kerner index, an index of thermal continentality, showed lower values than expected for certain particular types of vegetation. Parameters relating to the water balance turned out to be very discriminative for separating vegetation types according to the season or the month when water begins to be scarce. Thus, water availability in soils is a limiting factor for the development of vegetation in spring or autumn as well as in summer. As expected, precipitation and temperature discriminated the altitudinal levels of vegetation. Finally, these index limits only worked in the territories where they were formulated, or in nearby areas.     

Multivariate analysis of Gigantopithecus mandibles

Multivariate analysis of measurements of the teeth and mandibles of Gigantopithecus species has been conducted, using several methods. Results indicate Gigantopithecus is an aberrant form, less related to australopithecines and gorillas than the latter are to each other. Gracile and robust australopithecines differ considerably more than do male and female gorillas.     

Age and isotopic constraints on Pleistocene pluvial episodes in the Western Desert, Egypt

North Africa has undergone drastic climatic changes over the past several hundred thousand years. The timing of humid intervals called pluvials was investigated by uranium-series disequilibrium dating of travertines from the Kurkur Oasis, Western Desert, Egypt. The youngest and best dated travertines (70–160 ka) are found in Wadi Kurkur and include spring and lacustrine units exposed as 2 to 3 m high terraces. Travertines having an age of approximately 191–220 ka are exposed by differential erosion as linear mounds produced by spring systems over fracture zones in ancient wadis. The oldest travertines, having ages >260 ka, are extensive, cap limestone units above the oasis, and were deposited in paludal and lacustrine environments. Oxygen isotope ratios were measured for the wadi travertines (δ¹⁸O values ranging from 16.7 to 19.1‰ SMOW) and for spring mound travertines (18.5–20.5‰). Equilibrium oxygen isotope fractionation calculations indicate that the Kurkur travertines were deposited from waters having δ¹⁸O values similar to ancient Western Desert groundwaters ( −11‰, Sonntag et al., 1978a,b; Thorweithe, 1990; Sultan et al., 1996). The ages of the travertines correspond to times of monsoonal maxima, eustatic sea level high stands and interglacial maxima. Rainfall producing these groundwaters (and travertines) was significantly fractionated during atmospheric transport, in contrast to modern meteoric waters (−2.09‰, Joseph et al., 1992), implying a distant source for the pluvial waters. Increased precipitation, recharge of Western Desert groundwaters, and resultant travertine deposition are interpreted to be consequences of Milankovitch insolation cycle forcing, through enhanced Atlantic and Indian Ocean monsoons during interglacial time periods.     

Distribution and Contamination Status of Trace Metals in the Mediterranean Coastal Sediments,Egypt

Trace metals concentrations in sediments from the Egyptian Mediterranean coast were determined to evaluate the levels of contamination. The highest concentrations of metals were generally found in the middle region of the coast. Sediment pollution assessment was carried out using Enrichment Factor (EF), Geoaccumulation Factor (Igeo), Contamination Factor (CF), Modified Degree of Contamination (mCd), and Pollution Load Index (PLI). Association of adverse effects to aquatic life was determined using the classification of sediments according to three sets of sediment quality guidelines. The mean EF values were found to fall in the following sequence: Cr > Pb > Ni > Zn > Cu > Mn. The results demonstrated that the EF of metals in the sediments of the middle region was lower than those recorded in the western region and Rafah Station at the eastern region; the difference in the EF levels was significantly correlated with Fe concentrations along the study area. Based on the average Igeo of target elements, the Egyptian Mediterranean coast could be considered not polluted with Cr, Cu, Mn, Ni, Pb, and Zn (Igeo ≤ 0). The modified degree of contamination was >1.5, indicating zero to very low contamination. The calculated PLI were less than 1, indicating only baseline levels of pollution. There were small differences between the results obtained with the three used SQGs. Highly significant correlations were found between the concentrations of Fe, Mn, Co, Cr, and Ni, suggesting similar sources and/or similar geochemical processes controlling the occurrence of these metals in the sediments.     

Multivariate regression trees for analysis of abundance data

Multivariate regression tree methodology is developed and illustrated in a study predicting the abundance of several cooccurring plant species in Missouri Ozark forests. The technique is a variation of the approach of Segal (1992) for longitudinal data. It has the potential to be applied to many different types of problems in which analysts want to predict the simultaneous cooccurrence of several dependent variables. Multivariate regression trees can also be used as an alternative to cluster analysis in situations where clusters are defined by a set of independent variables and the researcher wants clusters as homogeneous as possible with respect to a group of dependent variables.     

Biogeographical relations of a hyperarid desert flora in eastern Egypt

The floristic composition and geographical elements of the study area were analysed resulted in 328 species representing 206 genera in 55 families. This study confirmed the record of fourteen species, mostly weeds, which can be considered as new additions to the flora of the study area. Therophytes were the dominant life form, while mono‐ and bi‐regional Saharo‐Sindian geoelements were the most represented. Ten species showed dominancy with their Q‐values ranged between 0.802 and 0.2, where Zilla spinosa and Zygophyllum coccineum were of common occurrence. Application of cluster analysis and DCA ordination techniques produced four major floristic groups (A–D) comprising seven subgroups. The correlation coefficients (r) between the different subgroups revealed high significant correlations (P = 0.01) between floristic group (B) and subgroup (C₂) and between subgroups (D₁) and (D₂). Significant correlations (P = 0.05) occurred between subgroup (D₁) and both of (A₁) and (C₂). Comparing the floristic similarities between this investigation and other relevant studies were presented and discussed. On the other hand, the low similarity index between the study area and Sinai may be attributed to the geographical position of both deserts where Sinai desert is part of the Irano‐Turanian region, while the Eastern Desert is a part of the Saharo‐Sindian region.     

Dairy goat grazing systems in Mediterranean regions: A comparative analysis in Spain, France and Italy

In order to maintain small ruminant grazing systems it is necessary to know precisely how they work and what actions can be taken to improve them. The objective of this paper was to characterize, classify, analyse and propose improvements for the dairy goat grazing systems in three countries from the western Mediterranean area: Spain, France and Italy. A multivariate analysis was conducted with 21 indicators obtained from the data collected from 45 farms. As a result of the multivariate analysis, 82.5% of variance was explained by two principal components. The first component included proportion of cultivated pasture area and cultivated pasture area per goat. The second included goats present and forage supply per goat. After conducting a cluster analysis based on these two principal components, farms were classified into four groups. Group 1 was made up of French and Italian farms, which had a smaller territorial base but a high cultivated pasture area per goat, contributing to greater self-sufficiency in feed. However the concentrate per goat was too high in relation to milk production, which was medium. The difference between milk income and feed cost is also medium. Group 2 was basically made up of Italian farms. The farms in this group had the most extensive management systems, with a low use of inputs. However, the milk production was low, meaning that the difference between milk income and feed cost was also low. Group 3 was mainly made up of Spanish farms. On these farms the concentrate supply was excessive and the forage supply was low. The milk production per goat was medium and the difference between milk income and feed cost was small. Group 4 was made up mainly of French farms. The farms of this group had a moderate supply of concentrate although the forage supply was very high. They had a high milk production, which lead to a large difference between milk income and feed cost per goat.The main weaknesses observed are related to feeding management, particularly grazing, and to the goat productivity. In the former case research on the nutritional utilization of rangelands and pastures and correct feed supplementation is to be encouraged. In the latter, the production capacity of the goats present in these systems should be improved, without forgetting the balance between hardiness and general productivity.     

Genetic variation among different populations of Aster tripolium grown on naturally and anthropogenic salt-contaminated habitats: implications for conservation strategies

The sea aster, Aster tripolium L., grows naturally in temperate regions, mainly in the salt meadows close to the coast. The species is also found in naturally and anthropogenically salt-contaminated inland habitats, such as potash mine dumps. The genetic relationships among populations from different habitats and correlations of the genotype with physiological and vegetational parameters were investigated. A. tripolium plants from five different sites close to the seashore on the North Sea island Baltrum, from five different potash mine dumps and, as an outgroup, from the seashore in Japan were probed. DNA was extracted from five plants from each of the 11 A. tripolium populations and analyzed for random amplified polymorphic DNA (RAPD). Altogether 35 polymorphic bands in 51 individuals and 45 different detectable genotypes could be identified. For evaluation of the genetic variation using RAPD bands, the neighbor-joining method, the principal coordinate analysis, and the analysis of molecular variance were applied, resulting in the classification into three genetic groups. A. tripolium plants from different ecological habitats on Baltrum were closely related while the plants growing at the deposit dumps showed a higher genetic diversity. The Japanese population was genetically very different from the German populations. Correlations between phytosociological and soil parameters and the respective genotype were not significant. The results argue for a conservation of anthropogenically salt-contaminated habitats to maintain genetic variability not only on the species level, but also within a species.     

不同干扰下阿拉善荒漠啮齿动物优势种对气候变化的响应

气候变化已对物种分布范围和丰富度产生了极大的影响。荒漠生态系统对气候变化的反应可能更加敏感。作为荒漠生态系统的重要组成者,了解荒漠啮齿动物特别是优势鼠种将对气候变化如何响应,对于荒漠地区生物多样性的维持将具有重要意义。2002—2010年,采用标志重捕法对阿拉善荒漠4种不同生境下啮齿动物优势种群进行了研究,分别利用Spearman相关分析以及典范对应分析(Canonical Correspondence analysis,CCA)对啮齿动物优势种群动态与年平均温度和年降水量的相关性进行了分析。结果表明,不同啮齿动物优势种对温度和降雨的响应不同,尤其以子午沙鼠表现最为显著。跳鼠对温度的适宜性要高于仓鼠科的子午沙鼠和黑线仓鼠,而仓鼠科啮齿动物对降雨的适宜性高于跳鼠。较小尺度上的人为干扰更可能从改变食性和生境的途径上加剧或缓冲降雨对荒漠啮齿动物优势种的影响,而不是改变温度对啮齿动物的作用。     

Floristics and environmental relations in two extreme desert zones of western Egypt

• 1 The present study provides quantitative estimates of soil, vegetation structure and species distribution in 144 stands along two transects in two extreme desert zones of western Egypt. This study had two aims: (1) to describe the floristic composition of the accidental type of vegetation growing in parts of the Western Desert of Egypt; and (2) to analyse the distribution of species in relation to certain environmental factors by multivariate data analysis.
• 2 Eight environmental variables were recorded: salinity, pH, calcium carbonate, soil moisture, organic matter content, and percentages of sand, silt and clay. A total of 60 species belonging to 19 families of the angiosperms and Ephedra alata was recorded. Chamaephytes and therophytes were the most frequent, denoting a typical desert life‐form spectrum, mainly of Saharo‐Arabian distribution.
• 3 The samples were classified into eight twinspan groups. Detrended correspondence analysis (DCA) showed that these groups could be distinguished by the first two DCA axes. They could also be effectively interpreted and explained with canonical correspondence analysis (CCA). Based on forward regression, salinity, fine sediments, organic matter and soil moisture content related closely to the first three canonical axes, and accounted for 84.1% of the species–environment relationship among the stands.
• 4 Both classification and ordination resulted in a clear demonstration of the vegetation pattern in the study area. Other twinspan groups were characterized in addition to those identified previously. In conclusion, the study area has a transitional character where the Nubian Desert and the Northern Mediterranean vegetation meet.

     

Multivariate analysis of climatic patterns of the Meditrranean basin

Climatic data from 444 weather-recording stations in the Mediterranean basin are examined by cluster analysis and principal component analysis. The application of numerical clustering distinguished several groups of climatic stations clearly interpretable in geographic and climatic terms. The hierarchical structure of the dendrograms could be used to identify at different scales uniform climatic regions. The complementary application of principal component analysis produced an ordination of climatic types, which clearly showed the main trends of variation in the precipitation and temperature patterns.     

Effect of protection and controlled grazing on the vegetation of a Mediterranean desert ecosystem in Northern Egypt

The present study provides preliminary assessments of the effect of protection and controlled grazing on the vegetation composition and phytomass in a Mediterranean desert ecosystem, 80 km W of Alexandria.Plots were fenced in 1974 and 1977, and different degrees of grazing pressure (no grazing, 25 and 50% of the grazing pressure freely practiced by the inhabitants) were applied. Changes in density, cover, frequency, phytomass and the phenological sequence of species were recorded and compared to those of the same species outside the fenced plots.Density and cover of perennials, frequency and presence of annuals, and total phytomass increased as a result of protection and controlled grazing. The arrangement of stands along ordination axes correlated with the degree of grazing pressure, which indicated that the distribution of species in the study area was more related to overgrazing than to the factors of the physical environment.Nomenclature of vascular plants follows Täckholm, V., Student's Flora of Egypt, Cairo University Press, 1974.This study was carried out within the framework of the Project of Regional Environmental Management of Mediterranean Desert Ecosystems of Northern Egypt (REMDENE), sponsored by the Egyptian Academy of Scientific Research and Technology, and supported by grants from the USA Environmental Protection Agency and the Ford Foundation.