RAPID: Decline and Resilience of White Ash Populations during an Emerald Ash Borer Invasion

University Of Kansas Center For Research Inc, Lawrence KS

Investigators

Abstract

This research represents a time dependent opportunity to better understand how white ash trees decline and potentially resist the invasive emerald ash borer beetle that threatens to eliminate ash trees from North America. The emerald ash borer was recently detected at a field station at the University of Kansas where 44 different populations of white ash from throughout the species range are all planted in one field site. The research will focus on understanding the effects of emerald ash borer on white ash populations that exhibit variations in physiology as a result of being adapted to different environments from which they originated. This variation may be key for understanding tree decline and potential resistance in response to emerald ash borer. The research will identify white ash populations that show rapid decline, slow decline, and no decline in response to emerald ash borer infestation, and identify mechanism(s) of ash mortality and potential resistance to emerald ash borers. Middle school students will be introduced to scientific research on important local tree species through active-learning sessions on invasive species and their effects on native vegetation. The results will inform public audiences on the effects of invasive species on conservation of native trees, and disruption of important ecosystem services provided by native plants. This research will determine mechanisms of intraspecific ash decline and potential resistance to the emerald ash borer that threatens to functionally extirpate the ash genus from North America. Emerald ash borer was recently detected at a white ash (Fraxinus americana) common garden site at the University of Kansas Field Station where 44 provenances from throughout the species range have been growing for several decades. Intraspecific variation in ash resistance to emerald ash borer is poorly understood and may be the key to maintaining the functional presence of ash in North America. This research will (1) identify potential white ash provenances with resistance to emerald ash borer and delineate critical compounds that contribute to this resistance; (2) determine the importance of physiological stress, emerald ash borer population density, and physical resistance capacity in ash response to emerald ash borer infestation; and (3) identify the physiological mechanism(s) of emerald ash borer-caused ash mortality. Measurements will be made of putative resistance compounds in phloem and the rate of wound-healing in mechanically-damaged phloem, as well as hydraulic status and potential for carbon starvation in dying (and resistant) trees as the emerging emerald ash borer infestation proceeds. The principle investigator will serve as a mentor for middle school students and will host active-learning sessions on invasive species and their effects on ecosystems. Undergraduate students will gain valuable hands-on research experience through assisting the principle investigator and postdoctoral fellow in data collection, writing of manuscripts, and outreach activities.