Assam, the bio-geographical gateway to North-east India, has Bhutan and Arunachal Pradesh to its north, Manipur and Nagaland to its east, Tripura, Mizoram, Meghalaya and Bangladesh to the south and West Bengal to the west. The ethnobotanical study was conducted in the Panikhaiti region, located in Kamrup (Metro) district of Assam, India. This area is characterised by semi-urban settlements, surrounding hillocks, and patches of undisturbed vegetation. The geographic location falls approximately between 26.1609° to 26.1634° N latitude and 91.8385° to 91.8455° E longitude, under the WGS 84 coordinate reference system (EPSG:4326).

Three field sites were selected based on preliminary surveys and local knowledge of plant availability and usage ( Table 1 , Figure 2 ).

This study was primarily based on extensive field inventories carried out to evaluate the ecological status of A. philoxeroides, commonly known as Alligator weed. The quadrat method was employed to assess phyto-sociological parameters such as Relative Density (RD), Relative Frequency (RF), Basal Area (BA), Relative Dominance (RDom), and Importance Value Index (IVI). These parameters were calculated for A. philoxeroides as well as associated plant species across three different sites in the study area.

Vegetation sampling was conducted using standard quadrat sampling methods. A total of 45 quadrats (15 per site) were sampled across the three selected locations. At each of the three study sites, quadrats measuring 1.5 m × 1.5 m were randomly placed within ecologically representative zones to capture the diversity and abundance of plant species. Quadrats were spaced at intervals of 4 to 8 meters, strategically covering both terrestrial and semi-aquatic microhabitats in and around Panikhaiti Gaon, Kamrup Metropolitan district, Assam. This sampling was conducted during the months between April, 2022 to December, 2023 without temporal replication. Plant species associated with Alternanthera philoxeroides were identified using standard regional floras, online botanical databases, and local ethnobotanical knowledge contributed by community members familiar with the vegetation of the area.

Ethnobotanical information was gathered through semi-structured interviews and informal discussions with local residents, including traditional herbal healers and knowledgeable elders. Repeated visits were made to reliable informants to validate the information. A total of 45 participants were surveyed in person using a structured physical questionnaire. This questionnaire included sections on the local, vernacular, and scientific names of the plant, parts used, methods of preparation, and the ailments treated with A. philoxeroides (Cunningham, 2001; Tardío and Pardo-de-Santayana, 2008).

In addition to the physical surveys, an online Google Form was used to collect supplementary data. The digital questionnaire comprised sixteen questions, divided into sections covering personal information of the respondent, plant identity, ethnomedicinal uses of A. philoxeroides, and perceived medicinal efficacy. Of these, twelve were required questions, and four were optional explanatory responses. While demographic profiling was not possible for this group, the responses yielded novel ethnomedicinal uses and aligned well with in-person accounts. Voluntary sampling is common in exploratory ethnobotanical studies, and the number of responses is considered acceptable given the specific, use-focused scope of the form (Tongco, 2007).

The overall data collection strategy is illustrated in Figure 3 .

The following standard ecological formulae were used to compute the phytosociological and biodiversity parameters:

E) Basal area (BA)

(Simpson, 1949)

n = total no of organisms of a particular species.

N = total number of organisms of all species.

I) Species richness index (Dmg) (Margalef, 1951)

S = Number of species.

N = Total number of individuals in the community

J) Shannon and Weiner diversity index (H) (Shannon, 1948; Shannon and Weaver, 1949)

Pi = Proportion of Individuals of the community

LN = Natural logarithm

K) Pielou’s evenness index (I) (Pielou, 1966)

H = Number derived from Shannon’s diversity index

S = Total number of species

Map-based visualisation of ethnobotanical collection sites was conducted using QGIS (v3.x). The geographical coordinates for three field sites, Site1, 2 and 3 were used to plot sampling locations. The Coordinate Reference System (CRS) was set to EPSG:4326 (WGS 84) to match the latitude-longitude data format. An OpenStreetMap XYZ basemap was added to provide geographical context.

Further, polygonal phytographs were constructed, using MS Excel, to visually compare phytosociological metrics, such as Importance Value Index (IVI), Relative Density (RD), Relative Frequency (RF), and Relative Dominance (RDom), across multiple plant species and sites.

Data visualisations were performed using RStudio (Posit Software, version 2024.12.1 Build 563, “Kousa Dogwood” Release). The demographic Sankey plot was generated using the networkD3 package in R. These visualisations were used to illustrate demographic distributions, ethnomedicinal data summaries, and ecological parameters computed during the study. Data derived from ethnobotanical questionnaires were summarised and plotted using the ggplot2 package. All codes used for data visualisation in this study is archived and accessible via Zenodo at https://doi.org/10.5281/zenodo.16080681.

The field surveys conducted during 2022–2023 across three distinct sites in Panikhaiti Gaon revealed seasonal trends in the life cycle and growth patterns of A. philoxeroides. The shoots of this species were observed to undergo senescence during the colder months, from the end of December to early February, followed by gradual regeneration beginning in March. The plant showed prominent and active growth during the pre-monsoon and monsoon periods, thriving especially in semi-aquatic and moist terrestrial patches.

A total of 31 plant species, including A. philoxeroides, was recorded across the three sites, belonging to 17 different families and comprising a mix of herbs, shrubs, climbers, and trees. Site-wise species count revealed 11 species in Site 1, and 10 species each in Sites 2 and 3. The phyto-sociological parameters, Relative Density (RD), Relative Frequency (RF), Basal Area (BA), Relative Dominance (R Dom), and Importance Value Index (IVI), were calculated for A. philoxeroides and its associated species across all three sites and are presented in Tables 2 – 4 respectively. Site 1 ( Figure 4a ) recorded the highest Importance Value Index (IVI) for A. philoxeroides (125.5), suggesting greater ecological dominance compared to Site 2 ( Figure 4b ) and Site 3 ( Figure 4c ). These phytographs visually convey the relative abundance and distribution of the species across different plant families in the surveyed habitats.

The associated plant families at each site varied in composition and dominance.

Additionally, ecological diversity across the three sites was assessed using Simpson’s Diversity Index (D), Species Richness Index (Dmg), and Pielou’s Evenness Index (I). Notable variation was observed in species richness and evenness across sites. Site 1 exhibited the highest richness (Dmg = 3.45) but lowest evenness (I = 0.21), suggesting dominance by a few species. In contrast, Site 3 showed lower richness (Dmg = 1.78) but higher evenness (I = 0.63), implying a more balanced species distribution despite fewer taxa. In terms of overall ecological diversity, Shannon’s diversity index (H) and Simpson’s index (D) also showed site-specific variation ( Table 5 , Figure 5 ), though with smaller effect sizes compared to IVI and evenness. Site 1, despite having the highest species richness, exhibited low evenness and diversity, suggesting dominance by A. philoxeroides. In contrast, Site 3 showed a more balanced species distribution, likely influenced by reduced human activity and less soil disturbance near the temple site.

While statistical analysis could not be applied due to single-value summaries, these trends point to meaningful differences in plant community structure across sites. These values are compiled in Table 5 and visualised in Figure 5 . Interestingly, several of the associated species were found to be of ethnobotanical relevance, some being used as leafy vegetables, while others were employed in traditional medicine by the local communities for treating a range of ailments.

One limitation of the present study is the absence of uninvaded control plots to assess directly the ecological impact of A. philoxeroides. Due to the widespread and patchy distribution of the plant across the study area, locating ecologically comparable sites free from its colonisation was not feasible. However, site-to-site comparisons revealed clear gradients in community composition, species richness, and dominance patterns, allowing for a relative assessment of its ecological influence. Future studies may benefit from a Before–After–Control–Impact (BACI) design or long-term monitoring of restored or managed sites where A. philoxeroides has been actively removed or suppressed, to capture its ecological footprint more explicitly.

Ethno-medicinal data were documented through structured questionnaires and in-person discussions with local residents and traditional herbal practitioners of Panikhaiti Gaon. These offline conversations helped to preserve and record valuable indigenous knowledge. The demographic details of the participants involved in this study are presented in Table 6 , and their distribution is illustrated in Figure 6 . The Sankey plot reveals a diverse age and occupational composition among the 45 respondents from Panikhaiti Gaon. Participants spanned multiple age categories, with notable representation from both younger (students) and older (herbal healers and elders) generations. The occupation-based categorisation included housewives, domestic workers, shopkeepers, and traditional healers, indicating that ethnomedicinal knowledge is maintained and transmitted across a broad social spectrum. This diversity implies towards the communal nature of traditional knowledge.

In addition to field interactions, responses were also collected through an online Google form, which helped document details such as which part of the plant is used, the method of preparation, and specific ailments treated. These ethnomedicinal insights, collected via the cloud-based survey from 26 respondents aged 18 to 70, are compiled in Table 7 .

Figures 7a-c represents a set of pie charts summarising the core ethnomedicinal knowledge shared by respondents.

The residents of Panikhaiti Gaon actively use A. philoxeroides in the treatment of a range of ailments. Most commonly, the plant is used to manage gastrointestinal issues such as diarrhoea, jaundice, and appetite loss. It is also applied in cases of anaemia, asthma, and acute cough, with several individuals confirming its effectiveness. Many participants described the herb as highly beneficial and said they would recommend its use to future generations.

Different parts of the plant, leaves, stems, and roots, are used either independently or in combination. These parts are often processed into juice, paste, or decoction form, depending on the condition being treated. The majority of participants indicated the use of the whole plant (50%) in traditional remedies, followed closely by the leaves (46%), and to a lesser extent, the stem (4%). This preference underscores a holistic approach to plant usage in local healing systems. The most common methods of preparation included paste (42%) and juice (31%), with some respondents also reporting the use of decoctions (19%) and powdered forms (8%).

Traditional herbal healers stressed the importance of considering patient-specific factors, such as age, overall health status, and the duration of illness, for safe and effective treatment. Interestingly, the data suggests that adults and older individuals in the community are generally more informed and experienced in traditional medicinal practices.

In addition to its medicinal importance, A. philoxeroides holds a place in the local cuisine of ethnic communities in Assam. The leaves, stems, and sometimes even the roots of this plant are regarded as edible, and are used in various traditional dishes, particularly during periods of food scarcity. Communities in and around Panikhaiti Gaon prepare this wild edible plant by steaming its leaves and stems or consuming it as a spinach-like green alongside staple meals. Owing to its high nutritional and proteinaceous content, the plant is considered a wholesome dietary component. However, informants also noted that frequent or excessive consumption could potentially lead to mild digestive discomfort, suggesting a need for moderation. Traditional dishes include Alligator weed curry prepared with locally available freshwater fish species such as Magur (Clarias batrachus), Sol (Channa striata), and Kawai (Anabas testudineus), all of which are delicacies in Assamese households. In some regions, a variation of pork curry is also prepared using A. philoxeroides, blending indigenous flavors with seasonal availability. These culinary practices reflect the adaptive use of local biodiversity within the community, extending the relevance of A. philoxeroides from ecological concern to a culturally embedded resource.