Mitigating pesticide risk on bee pollinators and angiosperm biodiversity in the Ndop wetlands: A conservation approach

Abstract

This study aimed to assess the risk of pesticides on bee pollinators and propose strategies to conserve entomophilous angiosperm species in the Ndop wetlands. Results showed that the applied pesticide doses were often excessive, increasing the exposure toxicity ratios (ETR). Among the pesticides, insecticides posed the highest risk to bee pollinators, with Emamectin benzoate (ETR=591.4) presenting the highest risk, followed by imidacloprid (ETR=517.5), fipronil (ETR=496.4), chlorpyrifos (ETR=240.7), and cypermethrin (ETR=131). Lambda-cyhalothrin (ETR=50.53) posed a possible risk. The study found that imidacloprid, fipronil, and chlorpyrifos posed definite risks through dietary exposure, while Emamectin benzoate, fipronil, and cypermethrin posed risks through direct contact. Approximately 46.03 % of angiosperms are anemophilous while 53 % are entomophilous with bee pollinators facilitating the pollination of nearly 90 % of the entomophilous species. To mitigate pesticide risks and for conservation purposes, farmers should refrain from applying pesticides during blooming and peak pollinator activity times, particularly midday.