Experimental test of plant defense evolution in four species using long-term rabbit exclosures

Plant defense traits have evolved over macro- and microevolutionary timescales in response to herbivores. Although a number of studies have investigated the evolutionary impacts of herbivores over short timescales, few studies have experimentally examined what defense traits most commonly evolve and whether multiple coexisting species exhibit similar evolutionary responses to herbivores. We addressed these questions using a long-term experiment at Silwood Park, England, United Kingdom, where we excluded rabbits from 38 grassland plots for <1 to 34 years. To assess the evolutionary impacts of rabbits on plant defense traits, we collected seeds from plots containing the following perennial species: Anthoxanthum odoratum L. (Poaceae), Festuca rubra L. spp. rubra (Poaceae), Holcus lanatus L. (Poaceae), and Stellaria graminea L. (Caryophyllaceae). We then grew these plants in a common garden, and measured defensive and morphological traits. We found some evidence for evolutionary change o...