HOLLOWS, PEEPERS, AND HIGHLANDERS: AN APPALACHIAN MOUNTAIN ECOLOGY

1. Prologue

1 1 Prologue I am an unabashed partisan of the Appalachian Mountains. It is not that there are rocky, majestic peaks here; quite the contrary: Eons of erosion have delivered rounded highlands that are approachable and gentle on the eye. But beneath Appalachia’s soft exterior run myriad short-lived scenes, each being played out by an individual organism competing for its part in the evolutionary play. No play runs in a vacuum, though. As G. Evelyn Hutchinson, the intellectual grandfather of many contemporary ecologists, put it, the long-term evolutionary drama can only be appreciated within the context of its environmental theater. The play is complex, showcasing a tremendous diversity of actors . Appalachia hosts more species of deciduous trees, salamanders, darters, and shrews than any other region of North America. Mosses, ferns, sedges, and heaths also abound. This huge variety of living things is due in large part to the highlands’ antiquity and convoluted topography. Appalachia’s beauty is dynamic, though, and every walk unique. Autumn colors, wing prints in snow, spring wildflowers, and a stream of tiger swallowtails punctuate my year. If you are open to it, every day will reveal a new sight, sound, or smell. Even in the dead of winter I can detect change in the tufted titmouse’s call, a shifting to the serious song of spring. I have written this book for three reasons. First, I want to share my excitement for viewing Appalachian plants and animals from an evolutionary perspective. Contemplating a leaf or laughing at a squirrel, friends often ask me, “What good is it?” or “Why does it 2 do that?” Such prodding questions provide this book’s thread: Most traits of a living thing exist because they have contributed to the reproductive success of that individual’s ancestors; therefore, the ultimate function of most traits we see in contemporary organisms is to promote the reproduction of the individual. According to this view, survival of the species is merely an incidental, statistical by-product of the behavior of many individuals, each selfishly pursuing its own reproduction. The essay “Autumn Leaves” registers my caveat on why “most” is underlined. I interpret the existence of an organism’s traits in terms of “why” questions in addition to “what” or how” questions. That is, I try to maintain an explicit distinction between what historical, evolutionary causes may account for the traits of an organism compared to how that trait develops and functions in an individual. The foundation for many of the following chapters, then, is the critical application of the theory of natural selection. This theory embraces some of the most basic concepts of evolutionary biology, such as adaptation , tradeoffs, and sexual selection. Grappling with such questions is called “selection thinking,” a type of logic introduced by Charles Darwin and reinforced more recently by George C. Williams, a contemporary synthesizer of evolutionary biology. Over the last twenty years, I have been applying the theory of natural selection to interpret the lives of organisms in my local environment. Viewed through this neo-Darwinian paradigm, I see individuals as life-long reproductive competitors and thereby have come to appreciate the role of conflict in shaping the daily routines of plants and animals. One of my priorities is to expose the conflicts that underlie the beauty and mystery of Appalachian life: violence among fireflies, sexual parasitism within frog choruses, deception by flowers. The bottom line is that natural selection has led to traits that best contribute to individual reproductive success, not necessarily to characteristics we would judge as generous or ethical. The second reason for writing this book stems from my experience as a teacher: I want to see people do more “backyard biology.” Even though the processes of photosynthesis and meiosis are cruHollows , Peepers, and Highlanders 3 cial to living systems, we cannot readily experience these concepts firsthand. We can, however, peer out a frosted window, identify a northern junco, and based on its size and color, predict whether it will drive off another flock-mate to steal its food or whether it is subordinate and will be displaced. Most of Appalachia’s living wealth is within a day’s drive of half the people in North America, an association that brings both advantages and disadvantages. On the positive side, our hills are close to long-standing centers of scientific research, so we have been able to...