Authors:M. Zaghloul, R. Abdel-Wahab, A. Moustafa and H. Ali
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 present study aims at analysing the vegetation of six riverian islands at Qena Governorate, Upper Egypt. 160 taxa of angiosperms and one pteridophyte species were recorded in six sedimentary islands located throughout the Nile stream at Qena Governorate, Upper Egypt. Of these, Hibiscus diversifolius (Malvaceae) recorded as a new record to the flora of Egypt. Therophytes represent 51.6% of the life form spectrum. Pantropical, Palaeotropical and Cosmopolitan elements (31.1%, 18.6% and 21.7%, respectively) were the dominant floristical categories among the total number of species. Vegetation analysis using TWINSPAN technique classified the 103 stands surveyed in the studied islands into ten vegetation clusters were obtained and categorised into 4 distinct groups according to soil moisture and chemical characteristics (TDS, EC, sodium and phosphate concentrations) appeared to be important attributes in characterising the vegetation clusters.
Authors:N. Naz, M. Hameed, M. Sajid Aqeel Ahmad, M. Ashraf and M. Arshad
Five distinct habitats along salinity gradient were explored for plant ecological attributes including soil plant interaction, vegetation composition and species distribution in the Cholistan desert. Higher saline sites supported
Aeluropus lagopoides, Cymbopogonjwarancusa, Ochthochloa compressa, Haloxylon recurvum
, whereas moderately saline habitats supported predominantly
Fagonia indica, C. jwarancusa
. The community structure and composition of each habitat type were very specific, the most dominant component being
. Each species has very specific relation to different environmental variables, and this reflects the habitat status, ecological adaptations and stress tolerance degree of the individual species. On the whole, it can be concluded that salinity alone was not responsible for the distribution of species at salt affected habitats.
Authors:F. Samu, F. Kádár, G. Ónodi, M. Kertész, A. Szirányi, É. Szita, K. Fetykó, D. Neidert, E. Botos and V. Altbäcker
Recent environmental and land use changes have made wildfires more frequent in natural habitats of the Kiskunság Sand Ridge on the Hungarian Plain. In a study initiated 2.5 years after an extensive fire that destroyed half of the area of a sand grassland — juniper, poplar forest steppe habitat, we assessed the effects of fire on two generalist arthropod groups: spiders and carabid beetles, as well as on the vegetation. Utilizing the natural experiment situation, samples were taken by pitfalls and suction sampling during a 1.5 years period in four 1 ha blocks, two of which were on the burnt part of the habitat, and two in the unburnt control. At the time of the investigation, in the burnt area the vegetation in the grass layer showed a quick but not complete recovery, while the canopy layer of the juniper bushes burnt down with no sign of regeneration. Carabid beetles and spiders showed differences in recovery after fire. In the carabid assemblages of the burnt parts — compared to the unburnt control — there were over three times more beetles, out of which significantly more represented the macropterous life form and granivorous feeding strategy. There was a higher ratio of pioneer species and a simplified assemblage structure in the burnt area, which meant that the conservation value of the carabid assemblage became lower there. In contrast, for the spider assemblage quantitative changes in abundance and species numbers were not significant, and the differences in species composition did not lead to a decrease in conservation value. Spider species in the burnt plots could not be described as pioneer species, rather they had ecological characteristics that suited the changed vegetation structure. Comparing the two groups, to repopulate the burnt areas, dispersal abilities proved to be more limiting for carabids. However, in both groups a strong assemblage level adaptation could be observed to the postfire conditions. In spiders, species with a stratum preference for the grass layer prevailed, while in carabids individuals with granivore strategy gained dominance. Thus, despite the differences in their speed, basically both assemblages tracked vegetation changes. The effect of future fires will depend on their scale, as well as land-use practices, such as grazing, that interact with fire frequency and recovery. If extensive fires in the future permanently change the vegetation, then it would also lead to a fundamental change in the arthropod fauna.
Authors:Shagufta Perveen, Muhammad Iqbal, Muhammad Saeed, Naeem Iqbal, Sara Zafar and Tehmina Mumtaz
phenolics, and more photosynthetic contents (chl. a and b contents) and could be grown under semi-aridenvironments to feed growing world population particularly in developing countries.
The authors would
Authors:Balázs Bényei, István Komlósi, Anna Pécsi, Margit Kulcsár, László Huzsvai, C. Barros and Gyula Huszenicza
Metabolic hormones [insulin, leptin, insulin-like growth factor-I (IGF-I), thyroxine (T4) and triiodothyronine (T3)], progesterone (P4) and beta-hydroxybutyrate (BHB) serum concentrations were evaluated and their effect on the superovulation results of donor cows was investigated in a semi-arid environment. Body weight, body condition score (BCS) and lactation stage were also included in the analysis. Twenty-three Holstein-Friesian cows were superovulated with 600 IU FSHp following the routine procedure and flushed on day 7 in a Multiple Ovulation and Embryo Transfer Centre in the semi-arid area of Brazil. The corpora lutea (CL) were counted and blood samples were collected for assays. All of the hormones investigated and BHB serum concentrations were within the physiological ranges. There was a positive correlation between hormones, except between BHB and all the others. The leptin level was influenced by feeding status, as indicated by the BCS. Insulin, T4, T3 and BHB levels were affected by milking status. Dry cows had higher levels of all hormones except BHB. An optimum level of leptin resulted in the highest number of CL, while the linear increase of P4, T4 and IGF significantly increased the number of CL.
Authors:A. Rascio, E. Carlino, G. Santis and N. Fonzo
This study is a multivariate discriminant analysis that was performed to identify a set of physiological characteristics that can be used to distinguish between groups of durum wheat genotypes differing for adaptation to semi-arid environments. To this aim, at first twenty-six genotypes were classified as “adapted”, “nonadapted” or “indeterminate” on the basis of yield and yield stability, as determined in a drought-prone environment of southern Italy, over a minimum of 4 and a maximum of 9 years. Subsequently fifteen morpho-physiological traits and the yields were assessed in a field study. Univariate statistical analysis of morpho-physiological traits to compare genotypes and groups of genotypes showed significant differences between the genotypes, although no single character could be used to discriminate between the genotype groups. On the contrary discriminant functions, based on 13 morpho-physiological traits, were effective for the full discrimination of all of the groups, with a 100% success rate. Four traits was the minimum needed to fully discriminate the “adapted” genotypes. Together with the water status parameter, the rheological properties and the affinity for bound water are new promising leaf traits, to distinguish between the plants coming from these different groups.
Hegazy, A. K. (2000): Intra-population variation in reproductive ecology and resource allocation of the rare biennial species Verbascum sinaiticum in Egypt. Journal of AridEnvironments , 44, 185-196.
Authors:Andrea Huisz, Tamás Kismányoky, Sándor Hoffmann, Tibor Tóth and Tamás Németh
): Aggregate Stability and Size Distribution in: Methods of Soil Analysis (Klute, A. ed.) Agronomy 9/1
Emerson, W. W. (1977): Physical properties and structure. in Soil factors and crop production in semi-aridenvironment. (ed: Russel