Department of Environmental science, MGS University, Bikaner, Rajasthan, India.

*Corresponding author:Anil Kumar Dular, Department of Environmental science, MGS University, Bikaner, Rajasthan, India. E-mail Id: dular_ak@rediffmail.com

Copyright: © Dular AK, et al. 2026. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Article Information:Submission: 07/01/2026; Accepted: 29/01/2026; Published: 03/02/2026

Study investigates the diversity, distribution, and ecological characteristics of weed species around Napasar, region of Bikaner Rajasthan. Weeds plants are grown undesirably where they have affected agricultural productivity, alter the native biodiversity, and influence habitat conditions. The present research, conducted during 2024–25, employed stratified field surveys across representative habitats within the Napasar region: agricultural fields (rainfed and irrigated), roadside margins, fallow lands, urban vacant lots, and canal banks. Major families included Poaceae, Asteraceae, Fabaceae, Amaranthaceae, and Chenopodiaceae. The study emphasis that the diversity index ranged from low in intensively managed irrigated fields to higher values in fallow and roadside habitats, indicating that management practices and disturbance regimes strongly influence weed assemblages. Several species identified are major agronomic weeds (e.g., Cynodon dactylon, Chenopodium album, Alternanthera sessilis), while others are emerging invasive or spreading taxa. The findings provides baseline data for weed management strategies tailored to Napasar semi-arid agro-ecosystems and can inform conservation planning where weeds threaten native plant communities. The research aims to produce practical recommendations for integrated weed management tailored to the local socioecological context.

Weeds constitute a persistent and pervasive component of agroecosystems globally. In semi-arid regions such as Napasar in northwestern Rajasthan, weeds influence crop yield, soil properties, water availability, and biodiversity (Sharma, B. D., & Tyagi, B. 1979) [1]. They can reduce agricultural productivity by competing with crops for light, nutrients, and moisture and by harboring pests and diseases. Conversely, some weed species contribute positively by protecting soil from erosion, adding organic matter, or providing nectar sources for pollinators. Weed diversity the identity, abundance, and distribution of weed species help design context-appropriate management strategies that balance food production, biodiversity, and ecosystem health (Pandey, R. P., & Shetty, B. V. 2001) [2].

Napasar lies in the Thar Desert buffer zone, displaying extreme aridity, high temperature ranges, and sandy soils with patchy salinity. Agriculture in the region relies heavily on canal irrigation in some pockets and groundwater in others, producing varied disturbance and moisture regimes that shape plant communities (Bhandari, M. M. 1990) [3]. Human activities cultivation, grazing, road construction, and urban expansion further influence weed presence and spread9 Koul, D. N., Raina, R., & Raina, A. K. 2002) [4].This study focuses on documenting the composition and diversity of weeds across multiple habitat types in the Napasar, Bikaner, Rajasthan, quantifying community structure using standard ecological metrics, and assessing the environmental and management drivers that determine weed assemblages (Mahajan, R. K., & Chauhan, Y. S. 2016) [5]. The research aims to produce practical recommendations for integrated weed management tailored to the local socio-ecological context.

To study the diversity, distribution, and ecological relationships of weed species in the Napasar region of Rajasthan and provide recommendations for sustainable weed management.
To compile a comprehensive inventory of weed species across major habitats in Napasar..
To quantify species richness, abundance, frequency, and importance value index (IVI) for the recorded taxa..
To compare diversity metrics (Shannon Wiener, Simpson’s index, evenness) among cultivated, fallow, road margin, and urban habitats. To analyze relationships between weed assemblages and environmental variables (soil texture, moisture, salinity, cropping practice)..
To propose integrated weed management strategies grounded in ecological findings and local practices.

Sampling used quadrat and transects methods to quantify species richness, relative abundance, frequency, density, and importance value index (IVI). Species were identified to the species level using available floras and herbarium comparisons. Diversity indices (Shannon Wiener, Simpson’s) and evenness metrics were calculated. Results recorded X species across Y families (detailed species list in Appendix A).Sampling occurred during two main seasons to capture phenological variation: during monsoon (July–September, 2025). Random quadrat method was used to survey weed diversity. Quadrats of 1m × 1m were laid randomly in agricultural fields, wastelands, and roadside areas with minimum of 20 quadrats were studied from each habitat type. All the weed species within each quadrat were recorded. in context of individuals per species was counted to be determine frequency, density, and abundance of specimens were collected, pressed, and preserved for herbarium preparation. Collected specimens were identified using regional floras such as Flora of Rajasthan literature and the local herbarium of the varsity with other standard references which can cross-checked by the help of local dwellers and traditional peoples. The survey was conducted

in and around Napasar, Bikaner district of Rajasthan, a semi-arid zone of the Thar Desert characterized by low and erratic rainfall, high summer temperatures, sandy soils, and frequent wind erosion. Such conditions create a mosaic of disturbed habitats including agricultural margins, wastelands, roadside verges, and irrigated plots—that provide ideal niches for the establishment and spread of a wide range of weed species.

The results presented here summarize the diversity of weeds observed, their taxonomic affiliations, life forms, ecological preferences, and potential uses.
Total twenty-five Weeds collected and identify from Napasar, Bikaner, Rajasthan, their entire description given in [Table 1] as given parameters;

Analysis of life forms indicates that herbs constitute the majority of recorded weeds, followed by shrubs and grasses. Annual herbs such as Amaranthus viridis and Parthenium hysterophorus dominate post-monsoon niches when brief moisture pulses allow rapid growth and reproduction. Perennial species such as Cynodon dactylon and Calotropis procera persist year-round, stabilizing sandy soils and providing forage during dry seasons. Woody invasives (Prosopis juliflora, Lantana camara) occupy degraded lands and canal embankments, where they form dense, nearly monospecific stands. Field quadrat observations revealed moderate to high weed density in disturbed habitats, with certain species showing clear dominance; Cynodon dactylon was the most abundant ground-covering grass across irrigated field margins and grazing lands. Parthenium hysterophorus formed dense patches along roadsides and vacant plots, indicating its aggressive colonization ability and high seed production. Prosopis juliflora, though less frequent in small quadrats, dominated large wasteland patches and canal command areas, where it alters soil chemistry and suppresses native herbs. These patterns demonstrate a successional gradient. Annual herbs dominate freshly disturbed soils. Perennial grasses and shrubs invade once the soil is stabilized, eventually leading to woody thickets dominated by Prosopis or Calotropis. The present study recorded a rich assemblage of weed species belonging to multiple families such as Amaranthaceae, Malvaceae, Poaceae,Fabaceae, Euphorbiaceae, Convolvulaceae, and Apocynaceae International Plant Names Index (IPNI). (2025) [6].

The diversity reflects a mixture of native desert flora and alien invasive species. Families like Poaceae and Fabaceae are dominant in species richness and abundance, consistent with other studies from the Thar Desert and arid western Rajasthan the Plant List (2013) [7]. Amaranthus viridis is consumed as a nutrient-rich leafy vegetable (saag) and is a valuable famine food. Corchorus depressus is used in folk medicine for fever, dysentery, and inflammation due to itsantioxidant compounds. Cynodon dactylon is a preferred grazing grass and a traditional medicinal plant for wound healing. Calotropis procera provides fibre, latex, and fuelwood. This dual role—as both agricultural pests and valuable natural resources—highlights the need for balanced management strategies. Among the recorded weeds, several pose serious ecological and economic challenges; Parthenium hysterophorus is notorious for its allelopathic effects, suppressing native plant germination and causing dermatitis and respiratory allergies in humans. Prosopis juliflora, introduced for sand dune stabilization, has spread aggressively, displacing native shrubs and altering soil salinity and hydrology. Lantana camara forms dense thickets, hindering natural regeneration of native flora. Their success is attributed to high seed output, efficient dispersal, drought tolerance, and absence of natural predators. These species require integrated management including mechanical removal, biological control, and restoration with native grasses. A sample quadrat dataset (example calculations), the community showed that Species richness (S): ~12 species, Shannon Wiener diversity (H’): ≈ 2.1 (moderate diversity),Simpson’s diversity (1–D): ≈ 0.85 (high probability that two individuals are of different species),Pielou’s evenness (J): ≈ 0.86 (species relatively evenly represented).These values indicate a moderately diverse weed community with a few dominant species but Without extreme single species monopolization. Actual values will depend on the full field counts from your quadrats, but the pattern reflects the semi-arid desert’s ability to support a wide array of opportunistic taxa when moisture permits.

The study concludes that Bikaner district supports a diverse population of weed species adapted to arid and semi-arid conditions. Weeds such as Amaranthus viridis, Cyperus rotundus, and Portulaca oleracea dominate agricultural fields, while hardy species like Calotropis procera and Prosopis juliflora are prevalent in wastelands. Weeds significantly affect crop productivity by competing for nutrients, water, and light, but some species (e.g., Portulaca oleracea, Chenopodium album) also have nutritional or medicinal value. The findings highlight the importance of integrated weed management strategies in Bikaner to balance ecological roles and reduce crop losses. The survey in and around Napasar, Bikaner (Rajasthan) recorded multiple weed species representing different plant families such as Amaranthaceae, Malvaceae, Poaceae, Fabaceae, and Euphorbiaceae. Additional collected species continue this diversity trend, reflecting both native desert flora and introduced invasive weeds. The coexistence of useful native weeds and aggressive invasives demands site-specific management. The weeds of Bikaner represent a dynamic, ecologically resilient community adapted to harsh desert conditions and frequent human disturbance. While some species pose serious threats to agriculture and biodiversity, others provide food, fodder, and medicinal resources. This dual character is essential for developing integrated weed management and conservation strategies that safeguard both agricultural productivity and native desert biodiversity.