Habitat management strategies regulate pest populations in managed landscapes by enhancing abundance of arthropod predators and parasitoids (natural enemies) via the provisioning of additional plant-based resources. To date, most studies of habitat management examine the role of these strategies in regulating natural enemy populations. What remains less well studied is whether habitat management practices lead to other beneficial effects for crops. With an increase in natural enemy abundance, habitat management may reduce rates of herbivory and thus enhance crop health in terms of photosynthetic output and growth. In addition, habitat management strategies may also have beneficial effects for pollinator abundance and diversity due to the presence of additional flowering plants in the managed landscape. Here, we examine whether a particular habitat management strategy, planting mixed gardens of vegetable and ornamental plants, reduces herbivory, enhances pollinator visitation rate, and influences crop growth and photosynthetic output. In an experiment conducted at the Oklahoma State University Botanical Gardens, we grew monocultures and polycultures of two vegetable (Lycopersicon esculentum ‘Mountain Fresh Plus’ and Vigna unguiculata ‘Early Scarlet’) and four ornamental species (Coreopsis grandiflora 'Early Sunrise', Echinacea purpurea, Gaillardia grandiflora ‘Arizona Sun’, Solidago sp. ‘Wichita Mountains’).
Results/Conclusions
Rates of herbivory were significantly lower among vegetable plants growing in polyculture plots than those growing in monocultures. In contrast, herbivore damage did not differ among ornamental plants growing in monoculture or polyculture. Additionally, some aspects of plant physiological status, pollinator visitation rate, and the composition of the pollinator fauna differed with planting regime. In total, our results demonstrate that a habitat management strategy in which vegetable and ornamental plants are grown in polyculture can reduce herbivory and lead to beneficial effects for plant health and pollinator visitation.
