Presence and management of the invasive plant Gypsophila paniculata (baby's breath) on sand dunes alters arthropod abundance and community structure

Invasive alien plants represent a global threat to biodiversity at multiple trophic levels, including arthropod communities which represent an important group of organisms in any ecosystem. Because of complex interactions among organisms, it becomes important when managing invasive plant species to consider impacts of both the invasion and management efforts on arthropods. In this study, we examined shifts in arthropod communities relative to invasion and management of Gypsophila paniculata (baby's breath), an invader of sand dune systems in Michigan, USA. We compared arthropod abundance and diversity for multiple trophic levels and functional guilds in invaded, managed, and reference plots from 2007 to 2010. Invaded plots had almost double the total numbers of arthropods and 20% more families than the reference and managed plots in 2008-2009. This was beyond a simple biomass effect due to the invasive plant. G. paniculata presence was also associated with an increase in sap-feeding herbivore abundance and dominance, increased pollinator and predator abundance, and increased family diversity in Hemiptera and Hymenoptera. There was no strong effect of management on arthropod communities, though a canonical analysis of principal coordinates indicated that reference and invaded plots were characterized by different families of arthropods. The consequences of these changes for the native plant community are unknown, and more mechanistic understandings of changes in biodiversity of higher trophic levels due to invasion and management are needed.