Invasive plants are a severe threat to biodiversity around the world. In North American tallgrass prairie grasslands, one of most invasive species is Chinese bushclover (Lespedeza cuneata). Lespedeza cuneata can reduce native plant diversity and biomass, interfere with pollination, and reduce seed germination in other species. How the presence of L. cuneata indirectly affects consumers is less well-studied. We investigated the effects of L. cuneata presence on the arthropod communities in an Oklahoma tallgrass prairie by sampling arthropods in plots with considerable L. cuneata invasion, plots without L. cuneata, and plots with L. cuneata manually removed. The arthropod community was examined at multiple trophic levels and feeding guilds.
Results/Conclusions
There was much seasonal variation in the response of the different arthropod groups. In the early portion of the season, herbivores tended to be more abundant in plots with L. cuneata, while later in the season, this difference largely disappeared. This trend was strongest for those herbivores that are phloem feeders. Carnivores, in particular specialists such as parasitoid hymenoptera, were generally lower in plots with L. cuneata, although this effect disappeared by the end of the season. There was no effect of L. cuneata on detritivore abundance. Our results show that an invasive plant can cause complex and seasonally variable effects on other consumers. This invasive species is therefore likely to cause a variety of changes in the tallgrass prairie food web.