The present investigation attempted to assess the impact of seed pre-treatments on the germination of Crotalaria persica (Burm. f.) Merr and Tephrosia apollinea (L) Pers. Equally important was our investigation to quantitatively compare different germination parameters used for seed germination studies. The results showed that the final germination was highest for both species under chipping (CHIP), sand paper (SP) and 20 to 90 minutes in concentrated sulfuric acid (SA20 to SA90). Rubbing in sand (SAND) and water-soaking (SOAK) showed lower germination percentages. Mean germination time (MGT) was highest after 50 minutes in sulfuric acid (SA50) for both C. persica and T. apollinea. The coefficient of velocity of germination (CVG) was highest when seeds were treated with sulfuric acid during 30 minutes (SA30) for C. persica (56.1%) and during 60 minutes (SA60) for T. apollinea (66.8%). For the germination index (GI), chipping and all SA exposures (except 90 minutes) revealed high means for both C. persica and T. apollinea, while SP also resulted in high germination index for C. persica. The mean rate of seed germination was highest under sand rubbing and distilled water (0.9 and 0.8, respectively) for C. persica and under SA20 (1.3), for T. apollinea. The germination rate index (GRI) for C. persica was highest under CHIP, SP, and SA20 to SA60. Timson Germination Index (TGI) showed high values for most pre-treatments. The highest TGI recorded was 45.6% for SA30. As for the correlation between the germination parameters, it is recommended that final germination percent coupled with germination index are used as germination parameters. They do not require complex calculations, while they complement each other in giving a representative evaluation of seed germination.

Geo-spatial technologies (i.e., remote sensing (RS) and Geographic Information Systems (GIS)) offer the means to enable a rapid assessment of terrestrial carbon stock (CS) over large areas. The utilization of an integrated RS-GIS approach for above ground biomass (AGB) estimation and precision carbon management is a timely and cost-effective solution for implementing appropriate management strategies at a localized and regional scale. The current study reviews various RS-related techniques used in the CS assessment, with emphasis on arid lands, and provides insight into the associated challenges, opportunities and future trends. The study examines the traditional methods and highlights their limitations. It explores recent and developing techniques, and identifies the most significant RS variables in depicting biophysical predictors. It further demonstrates the usefulness of geo-spatial technologies for assessing terrestrial CS, especially in arid lands. RS of vegetation in these ecosystems is constrained by unique challenges specific to their environmental conditions, leading to high inaccuracies when applying biomass estimation techniques developed for other ecosystems. This study reviews and highlights advantages and limitations of the various techniques and sensors, including optical, RADAR and LiDAR, that have been extensively used to estimate AGB and assess CS with RS data. Other new methods are introduced and discussed as well. Finally, the study highpoints the need for further work to fill the gaps and overcome limitations in using these emerging techniques for precision carbon management. Geo-spatial technologies are shown to be a valuable tool for estimating carbon sequestered especially in difficult and remote areas such as arid land.

The United Arab Emirates (UAE) has a unique experience in greening the desert. Huge efforts have been done to create green spaces across the country including afforestation and urban landscaping. Most of the landscaping designs were inspired from western landscapes comprises mostly of exotic species, which do not reconcile with the environmental conditions of the UAE. The intensive use of exotic species in artificial vegetation, high water requirements for the UAE greenery, coupled with water shortages and salinity, are causing major environmental and ecological challenges. Fortunately, the UAE hosts a unique flora and fauna that show remarkable adjustment to harsh weather conditions. Here we emphasize the use of native plants due to their potential to develop landscapes in saline and water shortage conditions, leading to reduced water usage for landscaping. The preservation of native biodiversity of the UAE will be an added benefit. In this article the main aspects of the UAE landscaping efforts, with the associated water resources using native plants in landscaping, problems in promoting native plants in landscaping and possible solutions are discussed.

Prosopis juliflora is one of the most problematic invasive trees in tropical and subtropical regions. Understanding driving forces affecting the potential global distribution would help in managing its current and future spread. The role of climate on the global spatial distribution of P. juliflora has been well studied, but little is known about the role of soil and human impacts as potential drivers. Here, we used maximum entropy (MaxEnt) for species distribution modelling to understand the role of climate (C), soil (S) and human impacts (H), C+S, and C+S+H in controlling the potential invasion range of P. juliflora, and to project its global potential invasive risk. We defined the top threatened global biomes, as predicted by the best-selected model. The incorporation of the edaphic factors improved the model performance and enhanced the accuracy of the outcome. Our findings revealed that the potential invasion risk increases with increases in mean temperature of the driest quarter (Bio9), soil alkalinity and clay fractions. Arid and semi-arid lands are at the highest risk of invasion than other moist biomes.