Ecology of floral visitors in Cumberland Plain Woodland undergoing restoration

Abstract

Restoration is key to retaining and improving the structure and function of ecosystems after disturbance. However, it is important to ensure that restoration actions result in the intended outcome. Pollination, a vital function within terrestrial ecosystems, is needed for the reproduction of flowering plants, and the long-term self-sustainability of restored areas. Insects are one group capable of performing pollination. Assessing the impact restoration has on insect floral visitors is the first step in understanding if pollination is supported. To do this, 17 sites in the Cumberland Plain Woodland (CPW), a critically endangered ecological community undergoing restoration (weeding, natural regeneration, and revegetation) were surveyed. Multiple methods were used to investigate how restoration actions are impacting floral visitors, and the possibility to support them through artificial nesting supplementation.

A seasonal one-year survey of floral visitor and flower interactions revealed that weeds and the introduced honey bee (Apis mellifera), play a prominent role in the floral visitor network. Pollard walks conducted for two years in summer, detected a higher abundance of butterflies within weeded areas than naturally regenerated areas. Deployed bee hotels, acting as artificial nesting, were primarily occupied by wasps. While bee hotels target native bees, wasps still provide important function in the CPW in the form of predation. However, the high level of parasitoid emergence, indicates that long-term deployment risks this artificial nesting supplementation becoming a population sink. These results highlight the importance of monitoring and assessment, to determine if the action taken is benefitting the functions of the restored areas. More restoration work is needed in the CPW, as the dominance by generalists and weeds indicate that this community is still impacted by disturbance.