The ecological impacts of the emerald ash borer (Agrilus planipennis): Identification of conservation and forest management strategies

The introduction of exotic species is the inevitable consequence of an expanding global society that relies heavily on international trade of goods and services. These introduced species have negative effects on biodiversity and disrupt native communities. In fact, the spread of non-native species is the second greatest threat to the loss of biodiversity next to habitat destruction.;The emerald ash borer (EAB), Agrilus planipennis Fairmaire (Buprestidae), is a recent example of an exotic forest pest species. EAB completes its life cycle on ash trees (Fraxinus spp.) including larvae feeding on cambium tissue which interferes with water and nutrient translocation. Once ash trees become infested with EAB, mortality is >99%. This dissertation was initiated after EAB was discovered and attempts to understand how EAB affects long-term forest community dynamics in order to provide practical applied conservation strategies. These research projects are designed to identify the ecological impacts of EAB and to determine long-term community changes to native deciduous forests. The research objectives are: (1) to identify consequences of EAB eradication efforts, (2) to determine altered community composition under different disturbance intensities (tree removal management recommendations) and (3) to design effective ex situ conservation protocols for future ash tree preservation.;EAB causes a disturbance to native forest by creating large light gaps through ash tree dieback; yet, EAB eradication efforts magnified the scale of disturbance through time and space which facilitated the establishment of invasive plant species. The tracked vehicles used during eradication also caused significant soil compaction. Management efforts applied to EAB-infested forests should prioritize appropriate tree removal techniques to minimize the disturbance to the surrounding community. Ash stands in close proximity to roads or edges, or near established invasive populations may benefit from proactive removal of invasive species. This research contributes to ash conservation efforts by providing a guideline for ex situ collection methods. By understanding diversity and spatial genetic structure of green ash (Fraxinus pennsylvanica ), a seed collection protocol has been constructed that optimizes the likelihood of capturing all alleles in a population while minimizing collection efforts. This cumulative research provides effective forest management recommendations and prioritizes ash conservation.