Balancing agriculture and conservation in the Ramsar-listed Kole paddy wetlands: The bee diversity and role of non- crop vegetation amid pesticide use

This study investigates the impact of pesticide use on bee diversity and the potential role of non-crop habitats in mitigating these effects in the Kole paddy wetlands, a Ramsar site in Kerala, South-West India. Bee populations were sampled over two years, in six pesticide treated and six non-treated control fields, along with adjacent bunds as non-crop habitats. A total of 173 bees representing 10 species across two families—Halictidae and Apidae—were collected. Species richness and Shannon diversity, were consistently lower in pesticide-treated fields compared to control fields. Non-Metric Multidimensional Scaling (NMDS) showed a distinct clustering of treated sites, indicating homogenized bee communities dominated by species such as Tetragonula sp. and Apis florea . In contrast, species like Halictus sp. were less common in treated fields. The bunds with dense vegetation, adjacent to treated fields showed a positive correlation with bee diversity, suggesting these areas act as refugia against pesticide exposure. Pearson correlation analysis revealed a significant positive relationship (r = 0.8389, p = 0.0369) between the diversity of treated fields and their adjacent non-crop habitats. Our findings signify the need for integrated pest management strategies that reduce pesticide use and promote the conservation of non-crop habitats, such as bunds to support pollinator populations, thereby ensuring the overall health and functioning of Kole paddy wetlands.