Quantifying the Soil Arthropod Diversity in Urban Forest in Dera Ghazi Khan

Arthropods can be either large or too small to be seen from the microscope. Their legs are jointed and perform a specific function in the soil. Several arthropods have been identified to date. Therefore, it is essential to identify them in a different type of soil. An experiment to quantify the soil arthropods in the urban forests of D.G. Khan was conducted at the Zoology lab of Ghazi University on four tree plants, i.e., neem (Azadirachta indica), mango (Mangifera indica), guava (Psidium guajava), and phalsa (Grewia asiatica). Soil samples were taken from different areas and on different months. The diversity of arthropods was analyzed through the Shannon index. The results were all significant. The total number of arthropods found in the experiment was 5151, with the following distributions: millipedes were 132 in neem, 133 in guava, 113 in mango, and 121 in phalsa; centipedes were 136 in neem, 142 in guava, 118 in mango, and 132 in phalsa; springtails were 138 in neem, 130 in guava, 120 in mango, and 134 in phalsa. There were a total of 12 different species of arthropods found. Neem (Azadirachta indica) have mites, centipede, and ants; guava (Psidium guajava) have centipedes and ants. Mango (Mangifera indica) have millipedes, centipedes, mites, springtail, and ants, and phalsa (Grewia asiatica) have mites, ants, and centipedes. The study reveals that millipedes, centipedes, springtails, and ants were found abundantly in the urban forest area of D.G. Khan, resulting in increased organic matter decomposition and appropriate distribution of nutrients through the soil having beneficial effects on the terrestrial ecosystem.

Migration and Deposition Law of Pollutants in Urban Sewage Confluence Pipe Network from the Perspective of Ecology

Aiming at the problem of pollutant migration and deposition in urban sewage confluence pipe, an experimental simulation system of sewage confluence pipe was established. The confluence conditions of three flow patterns (velocity ratio Vaccess/Vtrunk = 0.1/0.2, Vaccess/Vtrunk = 0.1/0.3, and Vaccess/Vtrunk = 0.2/0.3) were simulated. The changes of sediment thickness, carbon pollutants, nitrogen pollutants, and phosphorus pollutants in different confluence areas were analyzed, and the migration and deposition laws of various pollutants in urban sewage confluence pipe network under different flow patterns were revealed. The results show that when the flow velocity of trunk and branch roads changes, the deposition of various pollutants and the carrying capacity of water flow in the pipeline change, resulting in the change of sediment layer thickness and pollutant content. With the increase of trunk velocity, the sediment thickness in the area before and after confluence decreases, while the increase of branch velocity only reduces the sediment thickness in the area at the back of confluence. Under any flow pattern, the sediment thickness in the retention area (G3 and G4) shows an increasing trend, which is the key area of pollution removal. Under the three flow patterns, the content of carbon pollutants reaches the peak at the TCOD and SCOD values of G4 monitoring point. Increasing the trunk velocity can effectively reduce the content of carbon pollutants. The content of nitrogen pollutants in each flow pattern also reaches the maximum at G4 point, which are 213.6 mg/g, 205.2 mg/g, and 212.8 mg/g, respectively. Increasing the trunk velocity can effectively reduce the nitrogen content at points G1-G4, while increasing the flow velocity of the branch road can reduce the nitrogen content at points G5-G7. The distribution of phosphorus pollutants is complex, and the flow pattern needs to be adjusted according to different monitoring points.