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Predictive models were generated to evaluate the degree to which nine metals (Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb, and Zn) were absorbed by the leaves, stems and roots of forage sorghum in growing media comprising soil admixed with poultry manure concentrations of 0, 10, 20, 30 and 40 g/kg. The data revealed that the greatest contents of the majority of the metals were evident in the roots rather than in the stems and leaves. A bioaccumulation factor (BAF) < 1 was calculated for Cr, Fe, Ni, Pb and Zn; BAF values for Co, Cu, Mn and Cd were 3.99, 2.33, 1.44 and 1.40, respectively, i.e., > 1. Translocation factor values were < 1 for all metals with the exception of Co, Cr and Ni, which displayed values of 1.20, 1.67 and 1.35 for the leaves, and 1.12, 1.23 and 1.24, respectively, for the stems. The soil pH had a negative association with metal tissues in plant parts. A positive relationship was observed with respect to plant metal contents, electrical conductivity and organic matter quantity. The designed models exhibited a high standard of data precision; any variations between the predicted and experimentally observed contents for the nine metals in the three plant tissue components were nonsignificant. Thus, it was concluded that the presented predictive models constitute a pragmatic tool to establish the safety from risk to human well-being with respect to growing forage sorghum when cultivating media fortified with poultry manure.

Healthy coastal sabkhas (sabkha is an Arabic term for a salt flat) offer plenty of ecosystem services including climate change mitigation. However, fewer research studies were conducted at coastal sabkhas compared to other coastal marshes. This study was conducted in a total of ten coastal sabkha sites with different vegetation covers along the southern Red Sea coast of Saudi Arabia. The main objectives were to model and predict the distribution of volumetric soil organic carbon (SOC) density (kg C/m3) and cumulative SOC stocks (kg C/m2) using three different mathematic functions (allometric, exponential, and sigmoid) based on sampled and observed soil carbon (C) data (total of 125 soil cores = 1250 soil samples). Sigmoid function showed the greatest fit for predicting the distribution of volumetric SOC density over soil profile depth with mean Adj. R2 = 0.9978, 0.9611, and 0.9623 for vegetation cover of >25–50, >50–75, and >75–100%, respectively. For modeling the cumulative SOC stocks, both validation indices and p of the t-test confirmed that using the exponential function is the most appropriate to be used for predicting the SOC stock among different vegetation covers. Moreover, assessing the topsoil concentration factors (TCFs) showed that the distribution of the SOC content is impacted to a great extent by the vegetation cover at coastal sabkhas. Sampling the soil parameter of interest to estimate the SOC stocks is constrained by time and cost. Therefore, using the exponential function for predicting the distribution of cumulative SOC stocks at coastal sabkhas over soil profile depth is appropriate and promising for mapping SOC stocks at both regional and global spatial scales.

Lake Burullus is the second largest lake at the northern edge of the Nile Delta, Egypt, and has been recognized as an internationally significant wetland that provides a habitat for migrating birds, fish, herpetofauna, and mammals. However, the lake is experiencing severe human impacts including drainage and conversion to agricultural lands and fish farms. The primary goal of this study was to use multispectral, moderate-spatial-resolution (30 m2) Landsat satellite imagery to assess marsh loss in Lake Burullus, Egypt, in the last 35 years (1985–2020). Iterative Self-Organizing Data Analyses (ISODATA) unsupervised techniques were applied to the Landsat 5 Thematic Mapper (TM) and Landsat 8 Operational Land Imager–Thermal Infrared Sensor (OLI–TIRS) satellite images for classification of the Lake Burullus area into four main land-use classes: water, marsh, unvegetated land surfaces (roads, paths, sand sheets and dunes), and agricultural lands and fish farms. The overall classification accuracy was estimated to be 96% and the Kappa index was 0.95. Our results indicated that there is a substantial loss (44.8% loss) in the marsh aerial coverage between 1985 and 2020. The drainage and conversion of wetlands into agricultural lands and/or fish farms is concentrated primarily in the western and southern part of the lake where the surface area of the agricultural lands and/or fish farms doubled (103.2% increase) between 2000 and 2020. We recommend that land-use-policy makers and environmental government agencies raise public awareness among the local communities of Lake Burullus of the economic and environmental consequences of the alarming loss of marshland, which will likely have adverse effects on water quality and cause a reduction in the invaluable wetland-ecosystem services.

To better assess the relationship between excess nutrient runoff and plant species diversity in the Egyptian northern coastal lakes, the relationships between aboveground biomass, species diversity, and both micro and macronutrient concentrations in sediment, water, and plant materials were investigated. A total of 38 sampling sites were established for the five Egyptian northern lakes (8 for Bardawil, 10 for Manzala, 8 for Burullus, and 6 for each of Edku and Mariut). Sediment, water, and plant materials were collected and analyzed for both micro and macronutrients including nitrogen (N), phosphorus (P), sulfur (S), magnesium (Mg), calcium (Ca), potassium (K), iron (Fe), boron (B), sodium (Na), and aluminum (Al). Based on the Sørensen similarity index, Burullus and Mariut lakes were very similar (0.70) in their vegetation composition, while Bardawil Lake had no similarity with the rest of the lakes. In sediment, Mariut Lake had the highest total P concentrations (1.3 g kg−1), while Bardawil Lake had the lowest (0.3 g kg−1). Bardawil, a hypersaline lake, had the highest concentrations for both Na and B (9.6 and 0.1 g kg−1, respectively). Among the deltaic lakes, Mariut Lake water bodies had the lowest plant species richness. The current study indicated that the excessive agricultural and industrial nutrient runoff had a greater impact on the nutrient distribution pattern and negatively impacted plant species diversity at the Egyptian coastal lakes. An integrated management plan, including establishing more pretreatment facilities for runoff and wastewater, should be implemented to reduce the nutrient loads from the main industrial and agricultural runoff sources. Moreover, periodic monitoring and assessment for nutrient runoff reaching the lakes are necessary to help reduce eutrophication levels.

The Mediterranean Basin is the world’s second richest hotspot, and one of the most important locations on the planet for endemic taxa. However, there is no available up-to-date list of Mediterranean endemics. Available data are frequently insufficient or outdated. Therefore, this study aimed at delimiting the Mediterranean floristic region in Egypt, screening its Mediterranean endemics, and determining their habitats, life forms, flowering periods, dispersal types and phyto-geographical distribution. From a list of 275 Mediterranean endemic taxa in Egypt compiled from literature, this study reduced it to 57 taxa (including species, subspecies and varieties; 20.7%) belonging to 46 genera and 22 families. Fifteen major habitats harbored Mediterranean endemics in Egypt, with coastal dunes (17 taxa = 29.8%) and non-saline depressions (16 taxa = 28.1%) being the most represented. Moreover, the Mareotis (west) subsector was the richest (46 taxa = 80.7%). The largest number of taxa was recorded in North African sub-region (52 taxa = 91.2%), followed by Eastern (levant) sub-region (36 taxa = 63.2%). Therophytes were the most recorded life form, while ballochory was the most represented dispersal type. In conclusion, it is crucial to shed the light on Mediterranean endemics and provide an up-to-date documented database to help future management plan that support their conservation and sustainable use., La cuenca Mediterránea es el segundo hotspot más rico del mun-do y uno de los lugares más importantes del planeta en taxones endémicos. Sin embargo, no existe una lista actualizada de taxones endémicos medi-terráneos. Los datos disponibles son frecuentemente insuficientes o están desactualizados. Por tanto, nuestro objetivo fue delimitar la región florística mediterránea en Egipto, seleccionar sus plantas endémicas mediterráneas y determinar sus hábitats, formas de vida, periodos de floración, tipos de dispersión y distribución fitogeográfica. Partiendo de una lista preliminar de 275 taxones endémicos del Mediterráneo presentes en Egipto recopilada de la bibliografía, este estudio redujo ese número a 57 taxones (incluyendo especies, subespecies y variedades; 20.7%) pertenecientes a 46 géneros y 22 familias. Las plantas endémicas mediterráneas de Egipto viven en quin-ce hábitats principales, siendo los más representativos las dunas costeras (17 taxones = 29.8%) y las depresiones no salinas (16 taxones = 28.1%). El subsector Mareotis (al oeste) fue el más rico (46 taxones = 80.7%), mien-tras que el mayor número de taxones se registró en la subregión del norte de África (52 taxones = 91.2%), seguida de la subregión del este (levante) (36 taxones = 63.2%). Los terófitos fueron la forma vital más registrada y la balocoria el tipo de dispersión más común. En conclusión, es crucial arrojar luz sobre las plantas endémicas del Mediterráneo y proporcionar una base de datos documentada y actualizada que ayude a planificar una gestión futura que promueva su conservación y uso sostenible.

The aim of this study is to design de novo prediction models in order to gauge the likely uptake of eight heavy metals (Al, Cr, Cu, Fe, Mn, Ni, Pb and Zn) by Lycopersicon esculentum, the tomato plant. Uptake was assessed within the plant’s root, stem, leaf and fruit tissues, respectively. The plant was cultivated in soil amended by different application rates of sewage sludge, i.e. 0, 10, 20, 30 and 40 g/kg. The roots exhibited markedly elevated heavy metal concentrations compared to the above-ground plant components, with the exception of the quantity of Ni in the leaves. Apart from Al, Fe and Mn, a bioconcentration factor >1 was identified for all heavy metals. Excluding Ni in the leaves, all tested heavy metals exhibited a translocation factor < 1. The regression models were deployed to predict the accretion of the heavy metals under investigation within the various parts of L. esculentum. These were founded on the parameters of the equivalent eight heavy metals within the soil, pH and organic matter content. Student’s unpaired t-tests revealed no differences between the actual and predicted heavy metal concentrations in the roots, stems, leaves or fruits of the tomato plant. These data suggest an excellent model goodness of fit in terms of its accuracy to forecast the degree of heavy metal uptake. The constructed models may therefore facilitate the safe propagation of L. esculentum in growing media amended with sewage sludge, and concurrently provide a risk assessment with respect to human well-being.

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The ability of the native emergent macrophytes Typha domingensis for monitoring pollution with trace metals in Egyptian Lake Burullus was investigated through developing regression models for predicting their concentrations in the plant tissues. Plant samples (above-ground shoot and below-ground root and rhizome) as well as sediment samples were collected monthly during one growing season and analyzed. The association of trace metals concentration with several sediment characteristics (pH, organic matter, clay and silt) was also studied using the simple linear correlation coefficient (r). The concentration of some trace metals was significantly proportional to its values in the sediment such as Cd in the shoot, rhizome and root, Fe in the rhizome, and Ag in the root. There was positive relationship between the bioaccumulation factor (BAF) of Ag, Cd, Fe, Pb and Zn and sediment pH, organic matter and clay content. The developed regression models were significantly valid with high model efficiency and coefficient of determination, and low mean normalized average error. Trace metals were accumulated in the below-ground root and rhizome rather than in the shoot. Only Ag, Co and Ni provided bioaccumulation factor (BAF) < 1, while Ag was the only trace metal that could be transferred to some extend from the root to the rhizome and from there to the shoot [translocation factor (TF) 2.55 and 1.15, respectively]. Typha domingensis in Lake Burullus could be regarded as a bioindicator of trace metals pollution, and a good candidate as phytoremediator for Ag. The information on the phytoremediation capacity of T. domingensis certainly helps to solve contamination problems at Egyptian Lake Burullus region using this native plant.

The conservation of coastal ecosystems and specially mangroves ‘‘blue carbon’’ is receiving more attention as consequence of their recognition as high ecosystem carbon stocks and for the fact that these areas are undergoing land conversion. The aim of the present study is to evaluate the impact of land use changes due to conversion of mangroves to shrimp farms on the bulk density (SBD), organic carbon (SOC) concentration, and SOC stock in the sediments along the southern Saudi Arabian Red Sea coast. Shrimp farms and mangrove locations showed significant (P < 0.001) differences in SBD with high mean values in the sediments of shrimp farms. Shrimp farms and mangrove locations showed significant (P < 0.001) SOC concentration differences with high mean values in the sediments of mangroves. Considering the whole depth of sediment interval (0-100 cm), the highest value of SOC stock was recorded at mangroves (29.2 kg C m−2) and the lowest was identified at the locations of shrimp farms (19.9 kg C m−2). The results show that SOC stock of mangroves is 147% higher than that of shrimp farms confirming the fact that anthropogenic factors contributed significantly to SOC stock decrease. The mean cumulative potential carbon dioxide (CO2) emission due to loss soil carbon stock from mangrove conversion to the shrimp ponds was 34.9 kg CO2 m−2. In conclusion, the conversion of mangroves into shrimp farms contributed to the loss of SOC stock, therefore, the preservation of mangrove areas has an important value especially in arid areas such as Saudi Arabia. © 2019 Elsevier Inc.

Al-Jabal Al-Akhdar is an upland region which lies at the northeast part of Libya, in Cyrenaic. The study area is an N-S transect of about 30 km between El-Hamamah (near the sea level: 33º 53´ N and 21º 39´ E) to El-Bydda in the south (600 m above the sea level: 33º 17´ N and 21º 50´ E). This area is characterized by a wide physiographic variation that leads to distinguish of many habitats such as coastal saline sand flats, sand dunes, sand flats and hills, and inland plateau with terraces and wadis. 165 stands were sampled to analyze the vegetation of this area. 119 plant species were recorded (43 annuals and 76 perennials) including six endemic species. The composites have the highest contribution to the total flora, followed by the grasses and legumes. The application of two-way indicator species analysis (TWINSPAN) resulted in agglomerating of 30 vegetation groups at the level seven and six major ones at the levels three and two of this classification: Juniperus phoenicea -- Sarcopoterium spinosum that occupies a wide elevation gradient, Crucianella maritima -- Suaeda vermiculata along the seaward direction of the coastal hills, Retama raetam in the coastal sand flats, Pancratium maritimum -- Ammophila arenaria in the coastal sand dunes, Cichorium spinosum and Limoniastrum monopetalum in the saline sand flats of the coastal plain. The application of the detrended correspondence analysis (DECORANA) indicates reasonable segregation between these vegetation groups. Juniperus phoenicea -- Sarcopoterium spinosum group is the most prominent vegetation type in the study area (i.e. Mediterranean matorrals) where its diversity and cover increases with elevation reaching the Mediterranean forests at the highest elevated sub-humid zones., Le jbel Al-Akhdar représente une région de montagne située au nord-est de la Libye, en Cyrénaïque. Le secteur d'étude s'étend selon un transect nord-sud d'environ 30 kilomètres, entre El-Hamamah (près du niveau de la mer : 33º 53'N et 21º 39'E) et El-Bydda au sud (600 m audessus du niveau de la mer : 33º 17'N et 21º 50'E). Ce secteur se caractèrise par une variation physiographique importante qui conduit à distinguer beaucoup d'habitats tels que les étendues sablonneuses et salées de la côte, les dunes de sable, les escarpements et les collines de sable, et le plateau interne comportant des terrasses et des oueds. 165 relevés ont été effectués pour analyser l'organisation de la végétation de ce secteur. 119 espèces végétales ont été recensées (43 annuelles et 76 pérennes) dont six espèces endémiques. Les composées ont la contribution la plus élevée vis à vis de toute la flore, suivies par les graminées et les légumineuses. L'application de l'analyse bi-directionnelle d'espèces indicatrices (TWINSPAN) aboutit à l'agglomération de 30 groupes de végétation au niveau sept et six : la communauté à Juniperus phoenicea -- Sarcopoterium spinosum qui occupe un gradient altitudinal important, la communauté à Crucianella maritima - Suaeda vermiculata des collines côtières soumises aux influences marines, la communauté à Retama raetam des étendues sablonneuses côtières, la communauté à Pancratium maritimum -- Ammophila arenaria des dunes de sable, et la communauté à Cichorium spinosum et Limoniastrum monopetalum des étendues sablonneuses et salées de la plaine côtière. L'application de l'analyse de correspondance de type DECORANA indique une ségrégation correcte entre ces divers groupes de communautés. La communauté à Juniperus phoenicea -- Sarcopoterium spinosum (i.e. les matorrals méditerranéens) constitue le type de végétation le plus fréquent dans la zone d'étude ; ces matorrals se caractérisent par une augmentation de la diversité et du recouvrement parallèlement avec l'al