Existing Status of Acacia Woodlands in Central Saudi Arabia: A Case Study in Hawtat Bani Tamim and Al Duwadmi

Acacia woodlands are ecologically important and it is necessary to understand its structures and dynamics to develop sustainable conservation strategies. This study aimed to provide baseline information on the composition and growth of Acacia woodlands in the Hawtat Bani Tamim and Al Duwadmi regions of central Saudi Arabia. Height, diameter at breast height, crown diameter, seedling density, and soil seed bank content of Acacia tree species were characterized for 27 remote, circular, 0.1-ha plots in both study areas. At Hawtat Bani Tamim, Acacia raddiana, A. tortilis, and A. ehrenbergiana accounted for 45.53, 37.5 and 16.96% of all species present there. Most DBH were in the 6–10 cm class. A. raddiana was the main species in most diameter classes. Most trees were 4.1–5.0 m tall and A. raddiana predominated in this height class. Acacia ehrenbergiana had 92.63% damaged seeds. At Al Duwadmi, A. raddiana represented 78.99% of all Acacia trees there. A. gerrardii and A. tortilis accounted for 11.93 and 9.07% of the species there, respectively. Most of the DBH values were in the 6–10 cm and 11–15 cm classes, and A. tortilis and A. raddiana were abundant in both classes. Most trees were in the 4.1–5 m height class, which was dominated by A. raddiana. A. ehrenbergiana had 88.26% damaged seeds. In both areas, there was a gradual decline in the number of trees in DBH classes > 35 cm. The Acacia species in the two areas showed a fair regeneration status. There were more seedlings than saplings and fewer saplings than trees. This baseline study could contribute towards future sustainability planning initiatives after other assessment studies have been conducted to identify changes in the Acacia woodlands of this region. © 2021 Friends Science Publishers

Pollen analysis of animal coprolites recovered from vegetation mounds in El-Ga’ab paleolake: evidence for vegetation history of the desert of northern Sudan

In arid zones vegetation mounds are natural indicators for land degradation. Studying plants and animals remains in different strata of these mounds provide information about the past land use in which parts of the natural environment were modified into arable fields and pastures. They are suitable sites for preserving animal coprolites. In this study, two samples of different animal coprolites were collected from vertical trenches in vegetation mounds of Um Hilal and El-Hamra areas of El-Ga’ab depression in northern Sudan. Pollen grain analysis was conducted and eleven species that belong to eight families were identified. Five species recorded for El Hamra area and nine species were identified for Um Hilal area. Most of the pollen grains were identified as Suaeda monoica and Salsola imbricata which are halophytes indicates habitats of high soil salinity in El-Ga’ab depression. These species are still dominant in other law elevated areas of less dry sand dunes. Polygonum sp. Pollens were recorded in Um Hilal area indicating a moist habitat. Record of the comparatively large number of tree pollen grain of Acacia ehrenbergiana indicates no change in the dominant tree species. Presence of the pollen grains of Triticum sp. (wheat) and Heliotropium parciflorum is an evidence for past agricultural activities. This study recommended further intensive investigations of the old dry vegetation mounds distributed in the desert of northern Sudan to reconstruct its palaeoenvironment.

Phytochemical, antimicrobial and cytotoxicity screening of ethanol extract of Acacia ehrenbergiana Hayne grown in Jazan Region of Saudi Arabia

Purpose: To explore the phytoconstituents of Acacia ehrenbergiana Hayne as well as its biological effects. Methods: Determination of phytoconstituents of ethanol extract of the plant was performed by gas chromatography-mass spectrometry (GC-MS) technique. Antibacterial screening was conducted against the isolates of Gram-positive and Gram-negative microbes while the anti-carcinogenic properties of the ethanol extract on cancerous cells were investigated by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) cytotoxicity assay against breast MCF7, ovary cancer A2780 and colon cancer HT29 cells, respectively, in addition to normal MRC5 fibroblast cells. Results: GC-MS analysis identified 15 different phytochemicals in the ethanol extract. The extract exerted significant antimicrobial activity with the minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) in the range 1.56 - 6.25 and 3.12 – 12.5 mg/L, respectively, against all test bacterial strains. Cytotoxic activity, obtained by MTT assay, was 28.81 ± 0.99, 12.50 ± 2.50, 23.90 ± 0.74 and 50.58 ± 3.24 μg/mL, against the three cancer cell lines and normal fibroblast, respectively. MTT cytotoxicity results was further confirmed by clonogenic survival assay on MCF7 cells. Conclusion: This study highlights the potential interesting ethnopharmacological applications of Acacia ehrenbergiana Hayne to treat drug-resistant pathogens as standardized extract. Keywords: Acacia ehrenbergiana, Phytochemistry, Antimicrobial, Cytotoxicity

Woodcutting Activities in Tabuk Region (Saudi Arabia): Assessment of Conservation Knowledge

The present study aims to investigate the effect of different social factors on the woodcutting frequency in Tabuk Region. A total of 100 people participated in this study by answering the questionnaire questions. The conservation knowledge of the participants was also assessed through 4 questions (Yes or No). The final score of the conservation knowledge assessment is 4. The present study findings showed that most of people like to cut the wood for heating during winter and fall seasons. The frequency of woodcutting in Tabuk Region was once a month. Among the social factors involved in this study, education showed negative and significant relationship with the number of logging times. However, age had positive relationship with the number of logging times. The most favourbale species to be cut and used for heating and cooking in Tabuk are; <em>Acacia tortilis</em>, <em>Acacia ehrenbergiana, <em>Retama</em></em> <em>reaetam</em> and <em>Calligonum comosum</em>. For the assessment of the public conservation knowledge, it was found that most of participants had moderate to good conservation knowledge as most of them answered 3 questions correctly out of 4. The conservation knowledge showed to be affected positively by education level and negatively by the number of family members. In conclusion, it was found that there is remarkable woodcutting stress on wild plants in Tabuk Region and immediate and effective actions should be performed