Vol:.(1234567890) Environmental Science and Pollution Research (2024) 31:38128–38141 https://doi.org/10.1007/s11356-024-33763-3 RESEARCH ARTICLE Impact of Parthenium hysterophorus L. on floristic diversity in Dhauladhar foothills of Himachal Pradesh Aashima Raina 1  · Pratima Vaidya 1  · Jai Pal Sharma 2  · Hukam Chand Sharma 1  · Satish Kumar Bhardwaj 1 Received: 7 December 2022 / Accepted: 17 May 2024 / Published online: 25 May 2024 © The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature 2024, corrected publication 2024 Abstract Parthenium hysterophorus L. has become a weed of global concern owing to its fast expansion and invasive character. In order to study the status of this noxious weed and its impact on floristic diversity in Dhauladhar foothills, the study was conducted during the year 2021–2022 in culturable wastelands of Dhauladhar ranges in Kangra district of Himachal Pradesh, India. The impact of Parthenium hysterophorus L. on associated species at different altitudes and aspects was observed. Our observa- tions depicted that Parthenium hysterophorus L. has been growing more vigorously in the northern aspect than the southern aspect with the density of 37.78 m −2 and 21.62 m −2 , respectively. The highest density of this noxious weed was recorded in the altitudinal range of 600–1200 m (34.32 m −2 ) while it was not observed beyond 1805 m above sea level. The invasion of Parthenium hysterophorus L. significantly affected the plant density of other species. The descending order of the species as per dominance was observed as Cynodon dactylon, Trifolium repens, Oxalis latifolia, Parthenium hysterophorus L., and Ageratum houstonianum. The average number of species and species density were observed more in non-invaded sites (9.35 and 27.67 m −2 ) than in invaded sites (7.10 and 20.60 m −2 ). Species abundance and plant cover were observed more in non- invaded sites (28.73 and 657.90 m 2  ha −1 ) than in invaded sites (22.70 and 322.30 m 2  ha −1 ). Species diversity, richness, and evenness were reported to decline in invaded sites (1.56, 0.95, and 0.81, respectively) with respect to the non-invaded sites (1.94, 1.16, and 0.88, respectively). The study highlights the significant concerns associated with the invasive weed within the plant communities. Understanding its invasive status holds considerable implications for local afforestation initiatives, forest management strategies, and conservation policies. Furthermore, this investigation lays a foundational groundwork for implementing effective measures to get rid of this alien weed. Keywords Biodiversity conservation · Dominant species · Invasive weed · Species abundance · Species richness Introduction Parthenium hysterophorus L. is an annual, early maturing, upright herbaceous plant belonging to the family Asteraceae. The plant species is a result of natural hybridization between P. confertum and P. bipinnatifidum (Nath 1988). It is native to Mexico, Central America, and the Caribbean. The plant is considered one of the 100 most invasive species in the world by IUCN (GISD 2018; Weyl et al. 2019). This noxious herb has invaded 46 countries in the past two centuries. Evidences suggest the presence of this exotic invasive species in all Indian states. It invaded India as a contaminant in PL 480 wheat imported from the USA in the 1950s (Patel 2011). In India, this weed was first observed in Pune by Professor Pranjape in 1951, as a stray plant on rubbish heaps and later was reported by Rao (1956) as a new species in India. The earliest record of this species in India goes back to 1841 by Roxburgh in his book Hortus Bengalensis (Kaur et al. 2014). Parthenium hysterophorus L. is locally known as carrot grass, gajar ghas, white topi, chatak chandani, and con- gress grass. It has a deep tap root system with an erect stem which becomes woody on maturity. The plant can grow up to 0.5–1.5 m tall (Batish et al. 2012). The leaves Responsible Editor: Philippe Garrigues * Aashima Raina aashimaraina123@gmail.com 1 Department of Environmental Science, Dr. YS Parmar University of Horticulture and Forestry, Nauni – Solan, Himachal Pradesh 173230, India 2 Department of Tree Improvement and Genetic Resources, Dr. YS Parmar University of Horticulture and Forestry, Nauni – Solan, Himachal Pradesh 173230, India