Western Mediterranean Desert Research Articles

Threats affecting the distribution of Lygeum spartum Loefl. ex L. and its associated species in the Western Mediterranean desert of Egypt: Perspectives of conservation

The current study intends to evaluate the many hazards affecting the spread of the significant fodder grass Lygeum spartum Loefl. ex. L. and its associated species in Egypt's Western Mediterranean Desert over the past 60 years (from 1958 to 2020); depending on the data of the previous literature and the current situation evaluation by recent field trips. It also aims to assess its ecosystem services. Sixty-nine stands were collected from previous studies and unpublished data, in addition to 30 stands (10 m2) were added including 5 field trips during the period from spring 2019 to spring 2020. Measurements were taken to create a classification of this vegetation and to determine the main threats that affect its distribution composition. There are 142 species associated with the distribution of the studied plant in 6 habitats. While only 107 species were recorded in the recent stands in 7 habitats. Vegetation groups (G1- G8) obtained from TWINSPAN classification indicating that G1 (wadis) is the most diverse group with a species richness 34.7 species per stand, while G6 (dune) has the highest species turnover (4.57) during the period of 1958 to 2014. But in recent stands; G5 (saline and non-saline depression) is the most diverse group (30.875), while G2 (dunes) has the highest species turnover (4.819). Medicinal plants are the most represented (79.86%), followed by grazing plants (72.9%). The most common service is sand stabilization (92% of total services), followed by windbreak (natural) (40%). Threatened species represent 92.4%; habitat loss is the most affected threat (95 species), followed by over-collecting and over-cutting (82 species). Twenty out of 99 stands (20.2% of the total stands) have been destroyed due to human activity. Continuous monitoring of remaining patches of Egypt’s northwestern Mediterranean coast was required to save its natural flora from extinction.

Ecosystem Services of the Flora of Southern Mediterranean Desert of Egypt

The present study aims at characterizing the economic The present study aims to evaluate the economic plant species in the Western Mediterranean Desert of Egypt according to the goods and services that they offer and identifying the threat types that govern their gradual change in the study area. Of the 969 species recognized in this region, 548 have at least 1 potential or actual good (56.6% of the total species). Medicinal plants were the most commonly identified, while timber plants were the least. In addition, 338 species (34.9% of the total species) have at least 1 environmental service. Sand accumulators were the most common services, while water purifiers were the least. 411 species (75.0% of the total economic species) suffer from at least 1 type of threat. 267 species suffer from the over-collecting and over-cutting (65.0% of the total threatened species), while 36 species suffer from disturbance by cars or trampling (8.8% of the total threatened species). Physical defenses against threats were noted and sorted into 6 groups of species. Among those, species with hairy leathery leaves and hairy stems were the most represented, while the hidden species were the least common.

Phytomass and nutrient status of Kochia indica, a promising fodder plant in Egypt

The present study evaluated the above-ground phytomass and nutrient composition of the different organs of Kochia indica Wight, a summer annual weed, in relation to its phenological sequence in the Nile Delta region of Egypt. This plant attained its maximum phytomass, i.e. production, (1182 g dw/m2) and maximum contents of most the estimated nutrients during the vegetative stage. Its production is much higher than many of the vegetation types in the Mediterranean deserts which was partially related to differences in soil moisture and fertility. The nutrient content of this plant is as much or more than some of the forage species currently used for pasture, and many of the range species in the western Mediterranean desert of Egypt.

Mineral nutrient content and turnover rate of Mesembryanthemum crystallinum in the north-western desert of Egypt

A knowledge of the nutrient content of different plant organs is a necessary basis for the evaluation of the role of different nutrient elements in functioning of the ecosystem. The annual species Mesembryanthemum crystallinum concentrates excess Na, K and Ca in the vegetative organs at the standing dead stage. The total content of the different elements exhibited two distinct peaks. The first was during the late vegetative stage and included the elements Na, K, Ca and Mg while the second, during the standing dead stage, was made up of Ca and Mg. The turnover rate and time calculated in the present study indicate that M. crystallinum is well adapted to the environment of the western Mediterranean desert of Egypt. The accumulation of Ca and Na in the litter alters the habitat, inhibiting the growth of some of the associated annuals and permitting increased invasion by M. crystallinum year after year.

Sex expression in EgyptianThymelaea hirsuta (Thymelaeaceae) populations

The sex expression inThymelaea hirsuta was assessed in five habitats in the western Mediterranean desert of Egypt. The survey over two main flowering periods indicated that the sexual expression of this plant is complex and labile. Beside the dioecious male and female states, five monoecious states were detected. The dioecious states are more abundant and less labile. There is a clear shift from monoecious towards dioecious states and in general favour of males from the first (late autumn) to the second (late winter) flowering period. These results are discussed in view of the adaptive theories and evolution.

A phytosociological study on the inland desert plateau of the Western Mediterranean Desert of Egypt at El-Hammam

Phytosociological analysis of the inland plateau, one of the main habitats of the Western Desert of Egypt, indicates that Thymelaea hirsuta, Plantago albicans and Anabasis articulata generally predominate but, due to the remarkable local variations, five vegetational groups are recognized. Group I is dominated by Plantago albicans, group II by Anabasis articulata, group III by Thymelaea hirsuta, group IV by Anabasis articulata, Thymelaea hirsuta, Plantago albicans and Asphodelus microcarpus and group V by Scorzonera alexandrina, Helianthemum lippii and Echiochilon fruticosum. Among the soil variables analysed in the present study, texture, CaCO3, organic matter, phosphorus and the relative quantities of Na+, Ca++ and Mg++ are important in delimiting the vegetation groups.

Structure and standing crop of EgyptianThymelaea hirsuta populations

The population structure and standing crop of the desert shrubThymelaea hirsuta (L.) Endl. were evaluated in six different habitats in the western Mediterranean desert of Egypt. Under favourable conditions, populations ofT. hirsuta are denser and the size structure has a strong bias towards small, juvenile individuals, whereas the reverse tendency is found under adverse conditions with size structure biased towards big individuals. These results are discussed in the light of hypothesis of intraspecific competition. The standing crop is strongly affected by soil salinity and nature of soil surface (amount of exposed rocks).

Environmental gradients and species distribution in a transect at Omayed (Egypt)

An analysis of species distribution was made along a transect in the western Mediterranean desert of Egypt. About 20 per cent of species exhibit wide amplitudes of tolerance and exert local dominance. The largest number of species is found in marshes and dunes. Species abundance is lower on south- than on north-facing slopes where there is more moisture, silt, organic matter, phosphorus and potassium. Annuals and chamaephytes are the most frequent: a typical desert life-form spectrum. Subshrubs occur mainly in the transition between ridges and depressions (low moisture availability), and perennial herbs in depressions (high moisture availability). This indicates that subshrubs are drought enduring, while herbs are drought evaders. Soil properties control the distribution of species restricted to specific habitats more than that of widely distributed species.

Some aspects of land transformation in the western mediterranean desert of egypt

The western Mediterranean desert of Egypt has a long history of land-use. With recent development activities, land transformation is progressing at a high rate. Monitoring of changes to allow for predictions of long-term effects of these activities is viewed at three levels: (a) quantities of ecosystem components; (b) detailed distribution of patterns of land-use, vegetation and physiography; and (c) general distribution of the salient features of land. This study provides estimates at the first (a) and second (b) levels of changes in this region due to the main land-use types: grazing rain-fed farming, and irrigated farming.Grazing had little effects on soil characters, but it resulted in lower soil stability and abundance of plants and above-soil invertebrates. Irrigation resulted in water-logging and salinization, formation of calcic horizons, decrease in soil organic matter and soluble nitrogen, and in increase of above-and below-soil biota.A comparison of the distribution of vegetation and land-use in one of the sectors in 1964 and 1981, using maps based on aerial photographs and ground-truth data, indicated remarkable changes in areas of rain-fed farming, and in vegetation composition due to over-grazing.

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.

Systems Analysis of Mediterranean Desert Ecosystems of Northern Egypt (SAMDENE)

Natural and semi-natural ecosystems in many parts of the world are in the most serious danger of being degraded or lost through Man's mistaking short-term economic gains under temporarily favourable conditions for long-term stability. This is particularly obvious in arid and semi-arid regions where ill-advised land-use methods have led to profound and often irreversible changes. Under the austere conditions prevailing in such regions, the dynamic ecological equilibrium is fragile: minor changes in the physical environment entail dramatic changes in plant and animal life. These circumstances lead easily to desertification. Due to overexploitation of natural resources by Man (especially overgrazing, and overcutting of shrubs) in North Africa, desertification has proceeded at a rate of more than 100 square kilometres per year. There is a great need to establish scientific bases for the conservation and rational use of the resources of natural and semi-natural ecosystems, especially in regions fringing the deserts where these resources continue to disappear regularly and all too rapidly.The western Mediterranean desert of Egypt provides clear examples of such losses. As a result of the misuse of its resources, the region is producing at a rate that is probably far below its real potential. Agriculture (mainly barley cultivation) provides the livelihood for 74% of the population between Alexandria and Daba'a; this agriculture is either rain-fed (along most of the coastal strip), supplied by Nile and drainage-water mixed (Mariut Project, 500,000 feddan = 210,000 ha), or fed by irrigation and rainfall where Nile water is used as a supplementary source (Mariut Extension Project, 18,000 feddan). The most important land-use in terms of area, however, is animal husbandry (very largely sheep and goats, whose herding becomes more important and farming less important passing from the sea towards the interior). Actually there is overstocking, so that range vegetation is seriously depleted due to overgrazing and poor management.Various land-use policies have been tried in the past decades with varying degrees of success, though fig and olive cultivations, which act within the framework of the natural ecosystem and with minimum human intervention, have a remarkable record of viability.The Samdene Project (Systems Analysis of Mediterranean Desert Ecosystems of Northern Egypt) was conceived to bring together information on the Mediterranean desert ecosystems of northern Egypt. The Project involves the construction of predictive models simulating the major ecosystems of the region interms of energy flow and circulation of matter, and of spatial and temporal changes in plants and animals aswell as in soil features in relation to environmental variations.So he preliminary results are already offered on soil moisture, vegetation, effects of fencing, phenology, litter production, and soil fauna.