Plant ecotype affects interacting organisms across multiple trophic levels

Abstract

In plant conservation and ecosystem restoration, plants are often translocated to ensure or enhance plant survival and performance. While the effects of ecotype origin on the performance of translocated plants are increasingly acknowledged among researchers and practitioners, ecotype effects on associated communities and ecosystems have hardly been studied. This is critical because plants also constitute the habitat for a large number of interacting organisms, and many of them might be influenced by plant ecotype characteristics. Here, we studied different ecotypes of Centaurea jacea L., a plant species commonly used in grassland restoration, and their effects on seed herbivores and their parasitoids. We grew eight C. jacea ecotypes originating from different regions in Germany in a common garden and found that the ecotypes differed up to three-fold in the frequencies of seed herbivores. These differences appeared to be mainly driven by ecotype differences in flowering phenology. We also found that there were up to four-fold differences in the frequencies of parasitoids, and even up to nine-fold differences in the abundances of parasitoids among ecotypes. In summary, plants from different origins substantially differed in their effects on interacting organisms, potentially reflecting coevolutionary relationships across trophic levels. The introduction of foreign ecotypes in restoration projects may thus not only affect the plants themselves, but it may also disrupt the balance of their biotic interactions.