Multiple Disturbances and the Turbulent Forest

Abstract

I have always been drawn to change, whether I liked it or not. As a kid, I was obsessed with dinosaurs and their extinction, all while having to move constantly as a Navy brat. As an adult, I am devoted to understanding how and why systems change, likely inspired by the unending change of my childhood. However, as I matured, I realized that change is almost never spurred by a single event, but rather a multitude of shocks to the system. This dissertation focuses on the complexity of multiple ecological disturbances and highlights their importance in the world. Using several multi-disturbance experiments, I explore a wide variety of disturbance interactions in the temperate deciduous forest. The first chapter of this dissertation focuses on how deer and canopy gaps influence invasive earthworms, shedding new light on how aboveground events can change belowground communities. The second chapter builds upon the first and tests how combined deer and canopy gaps influence understory regeneration over 15 years, with some reference to invasive earthworms. Lastly, the third chapter explores how combined fire, deer, and canopy gaps change the seed bank over 13 years. Each of the aforementioned disturbances are common and influential in eastern forests, although they are not often studied together. In each chapter we find that community responses vary depending on the disturbances in question. This dissertation is meant to highlight how little we know about the many ways in which multiple disturbances change ecosystems and how critical it is that we start to study these complex drivers of change, particularly as the climate warms and disturbances become more frequent on the landscape.