Search

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.