Abstract

The collective impact of urban air pollution on endemic plant species in urbanising landscapes relative to other ecological stressors is still poorly comprehended despite its importance as a major ecological stressor. The paper examines the effects of urban air pollution gradients on pollinator activity, the rates of insect herbivory, and the level of reproductive performance of endemic shrubs. Our hypothesis was that as the level of pollution rose, the abundance of pollinators would decline, the level of herbivory pressure would rise, and this would lead to a decline in the level of reproductive success of plants. Field surveys were performed within a clearly defined urban air pollution gradient (i.e., low, medium impression of air pollution, and high) and pollinator visitation, herbivory damage, and reproductive measures (fruit and seed set) were measured in an orderly manner. The relationships between air pollution indicators and biological responses and considering site-level variable differences were analysed with the use of Generalised Linear Models and Generalised Linear Mixed Models. These findings indicated that there was a very strong negative relationship among air pollution, pollinator abundance, and high levels of herbivory and significant reductions in reproductive success in the high pollution locations. These results not only indicate the interactive nature of atmospheric pollution into the ecological interaction of multi-trophic systems but also show how endemic shrub species are vulnerable to the atmosphere. The paper presents powerful, model-supported findings of the necessity to have a combined approach to air quality monitoring and biodiversity protection in cities.