Anthropogenic changes influence bee populations, floral resource, and land cover change in Mount Rungwe Nature Forest Reserve

Abstract Background: Globally, anthropogenic activities are known to influence land and vegetation cover, bee populations, and floral resources, particularly in tropical rainforests. This study investigates the impact of anthropogenic disturbances on land and forest cover changes, wild bee populations (i.e., diversity and abundance), and floral resources in the Mount Rungwe Nature Forest Reserve (MRNFR). Methods: We employed Geographic Information Systems (GIS) and Remote Sensing (RS) techniques to analyze forest cover changes in MRNFR from 2010 to 2025. Wild bee diversity and abundance were assessed using a combination of pan traps and sweep nets, while flowering plants were visually counted to estimate the average floral abundance in each plot. Only flowering shoots with open and non-wilted flowers were included in the counts. Results: The results revealed that in 2010, dense forest was the dominant land cover class. Transitions of dense forest, open forest, and grassland into bare land between 2010 and 2025 indicate the presence of human activities. Also, the study revealed the significant differences in wild bee diversity and abundance across habitats experiencing varying levels of anthropogenic disturbance namely, that is, highly disturbed, moderately disturbed, and less disturbed areas. Wild bee abundance in less disturbed habitats was approximately twice that of highly disturbed areas. Moreover, both moderately and less disturbed habitats supported greater species diversity compared to the highly disturbed sites. Similarly, floral abundance was the lowest in highly disturbed habitats, suggesting that the availability of floral resources directly influences wild bee populations. Conclusion: These findings indicate that anthropogenic activities significantly reduce the abundance of flowering plants that provide essential foraging and nesting resources for wild bees. Overall, our results underscore the importance of conserving and managing forest habitats, as habitat degradation and the loss of floral resources are closely linked to declines in wild bee populations.