A Study on the Selection and Application of Bee- and Butterfly-Friendly Nectar Plants in Guangzhou’s Urban Parks

Urban parks serve as important conservation habitats for flower-visiting bees and butterflies in urban areas. However, systematic evaluation and screening of bee- and butterfly-friendly nectar plants adapted to the subtropical climate of South China remain limited. In this study, an evaluation framework was developed to assess the landscape application potential of nectar plants. The framework incorporated four dimensions: ornamental value, bee and butterfly attractiveness, ecological adaptability, and flowering period. Utilizing the Analytic Hierarchy Process (AHP), common nectar plants in Guangzhou’s urban parks were evaluated based on 14 specific indicators: leaf shape, leaf color, flower color, flower size, fragrance, visitation frequency, visitor diversity, waterlogging tolerance, heat tolerance, shade tolerance, barren tolerance, nativeness, flowering duration, and flowering phenology. The results indicated that among the 14 indicators, visitation frequency (0.2252), heat tolerance (0.2044), barren tolerance (0.1473), waterlogging tolerance (0.1400), and flowering duration (0.0543) ranked as the top five weights, significantly influencing the comprehensive quality of the nectar plants. The weight ranking of the criteria layer was ecological adaptability (0.5824) > bee and butterfly attractiveness (0.2815) > ornamental value (0.0709) > flowering period (0.0652). The comprehensive scoring revealed that herbaceous plants scored slightly higher overall than shrubs. The top-ranking species included Duranta erecta L. (4.8409), Mecardonia procumbens (Mill.) Small (4.7377), Heptapleurum heptaphyllum (L.) Y. F. Deng (4.6579), Farfugium japonicum (L.) Kitam. (4.6579), Ixora chinensis Lam. (4.5763), Salvia farinacea Benth. (4.2001), and Asclepias curassavica L. (4.2475), with native and herbaceous plants demonstrating outstanding performance. The application of the AHP effectively facilitated the comprehensive evaluation of nectar plants, and the evaluation outcomes aligned closely with the field observations of bee and butterfly visitations.