Objective The canal system is crucial for altering the hydrological processes in agricultural irrigation areas and serves as a vital ecological network within these areas. The canal corridor habitat, an important habitat for various organisms, plays a significant role in maintaining biodiversity in irrigation areas. The Dujiangyan Essence Irrigation Area, located in the southeast of Dujiangyan City in Chengdu, is an important site for biodiversity conservation and a key component of the regional green space ecological network. Studying the composition and diversity characteristics of spontaneous plants in different habitats within the canal corridor of the Dujiangyan Essence Irrigation Area is beneficial for biodiversity conservation and the optimization of canal corridor landscape.

Methods This research conducts a comprehensive survey of spontaneous plants in spring, collecting data from 81 sample points and 167 quadrats. Habitats are categorized into six types: semi-natural revetment, hard revetment, wasteland, artificial green space, hard plot and self-use vegetable plot habitats. Community composition analysis is performed using Two-way indicator species analysis (TWINSPAN), and the diversity of spontaneous plants in different canal corridors and different types of habitats is compared by Kruskal-Wallis test.

Results 1) A total of 257 species of spontaneous plants belonging to 180 genera and 79 families, are recorded in the canal corridor of Dujiangyan Essence Irrigation Area. These species encompass 10 life forms, with perennial herbaceous plants being the most abundant, followed by annual and biennial herbaceous plants. In terms of species origin, native spontaneous plants account for 42.02% of the total, representing the largest proportion. The life forms of the dominant species are mainly annual and biennial herbaceous plants and perennial herbaceous plants, and the species origins of the dominant species are mostly native and domestic species. 2) 15 dominant clusters are identified on revetments and 24 ones on shores. Dominant clusters without invasive species can serve as references for plant community construction in specific habitats. For example, revetment clusters II, III, and XIII are suitable for hard revetment habitats; shore cluster VII can be used for artificial green space and hard plot habitats, while cluster XIX is appropriate for wasteland and self-use vegetable plot habitats. 3) Significant differences are observed in species composition, life form composition, species source and dominant species composition among the six habitat types. The species composition of different habitats is studied, and it is concluded that wastelands have the highest richness in families, genera, and species, while semi-natural revetments have the lowest. Classification and statistics of species life forms in different habitats are carried out, and the results show that, except for the semi-natural revetment habitat, the life forms occupying the highest proportion are annual and biennial herbaceous plants and perennial herbaceous plants. Semi-natural habitats have a higher proportion of perennial herbaceous plants and shrubs. Hard revetments, artificial green spaces, and self-use vegetable plots have the highest proportion of annual and biennial herbaceous plants, while semi-natural revetments, wastelands, and hard plots have the highest proportion of perennial herbaceous plants. The importance value of dominant species is the highest in hard revetments and lowest in artificial green spaces. Semi-natural revetments have more native dominant species, whereas self-use vegetable plots have more invasive dominant species. Diversity indices also show significant differences, particularly between hard revetments and other habitats, with hard revetments consistently having the lowest values.

Conclusion The research reveals significant differences in species composition and diversity among different habitats within the canal corridor of the Dujiangyan Essence Irrigation Area. In hard revetment habitats, ferns are not only dominant but also serve as indicator species and dominant species in the dominant clusters, highlighting their critical role in revetment habitats, especially in hard revetments. The frequent occurrence of Papermulberry (Broussonetia papyrifera) as an indicator species in wasteland and self-use vegetable plot habitats suggests its strong adaptability and potential as a high-quality native tree species, warranting further investigation. Hard revetments exhibit the lowest species richness, diversity, and evenness, likely due to the use of anti-seepage materials to maintain irrigation efficiency and reduce water infiltration. The relationship between revetment materials, construction practices, and biodiversity merits deeper exploration to inform future ecological water conservancy projects. Additionally, protecting dominant spontaneous plant species and communities in different habitats, as well as strengthening dynamic monitoring and timely removal of invasive species, are essential for sustainable ecological management.