Occurrence and Ecological Impacts of Invasive Aquatic Weeds in Lahore, Pakistan

Abstract

The present study was conducted to establish baseline information on the diversity, distribution, and ecological implications of aquatic weeds in Lahore and surrounding habitats. Field surveys were carried out between 2021 and 2023 at randomly selected sites including Kasur Road, Raiwind Road, Thokar Niaz Baig, Gajjumatta, and Shahdara, where drains and ponds were sampled and aquatic flora identified using standard floras and expert consultation. Water quality parameters indicated generally eutrophic conditions, with dissolved oxygen ranging from 4.5 to 9.2 mg/L (mean 6.8 ± 1.1 mg/L), electrical conductivity from 300 to 750 µS/cm (mean 520 ± 95 µS/cm), and turbidity between 7 and 36 NTU (mean 21.3 ± 6.7 NTU). A total of six dominant taxa were documented, with Eichhornia crassipes showing the highest frequency (86 ± 4.1%), density (63 ± 5.3 ind./m²), and cover (65 ± 3.8%), followed by Lemna minor (74 ± 6.2% frequency; 88 ± 7.4 ind./m² density; 53 ± 2.9% cover). Emergent species such as Typha angustifolia and Phragmites australis exhibited moderate distribution (57–60% frequency), while Pistia stratiotes (33 ± 3.6%) and Microcystis aeruginosa (25 ± 4.2%) were less abundant. The predominance of free-floating weeds, particularly E. crassipes and L. minor, highlights their adaptability to nutrient-rich and stagnant waters and underscores their role in altering aquatic ecology by reducing light penetration and oxygen availability. This first systematic report from Lahore emphasizes the urgent need for continuous monitoring and integrated management strategies, while also pointing to the potential utilization of invasive weed biomass in sustainable practices such as composting and biochar production.