Some invasive plants threaten native species, limit plant variety, and frequently result in the extinction of several native species with commercial value. The current study was conducted in Jeddah, Saudi Arabia, a semi-arid region where droughts are becoming more severe because of climate change. The purpose of the current study was to study the effects of Prosopis juliflora on native species as well as soil parameters. The current results showed that aridity of the study area increased from the period between 1970 and 2021, as shown by a decline in the Lange, Emberger, and De Martonne aridity indices by 36%, 33.5%, and 0.5%, respectively. P. juliflora has been observed in a wide variety of habitats, including sand dunes, marshy wetlands, and inland wadis. P. juliflora enhanced phenolic content, salinity, salt, potassium, nitrogen, phosphorus, and organic matter while decreasing soil acidity. More than 63% of the species in North and South Jeddah associated with the P. juliflora tree disappeared, and the density of the remaining species decreased by 54% to 97%. Annual species had the largest percentage of the vanished plants, with 82% in South Jeddah and 66% in North Jeddah. The current study shows the extent of the P. juliflora threat to local plants, especially that the region is exposed to greater drought because of climate change, which requires taking the necessary precautions and good management to limit the spread of this invasive plant. The current study is considered an important step that can provide important information on the effects of P. juliflora on Asia’s biodiversity.