The influence of native plants on arthropod population dynamics: can native plants enhance conservation biological control

Abstract

Conservation biological control aims to maintain sustainable natural enemy populations. Through increased urbanization, alien vegetation is being planted; these plants may be unacceptable hosts for herbivores. We tested the prediction that urban landscapes composed of native plants host a diverse herbivore population and attract and sustain a diverse community of natural enemies relative to landscapes composed of alien plants. Native and alien landscapes were created to test this prediction. I compared the colonizing arthropod communities, herbivore survival and the aesthetic injury of trees and shrubs in native and alien landscapes. In this two year project, I found only weak evidence to support my predictions. Native landscapes did not host an arthropod community significantly different than alien landscapes. There was a trend for several natural enemy families to have a greater abundance in native landscapes. This did not have an impact on herbivore survival or aesthetic injury of the plants.