Introduction

Interesting Times

This is the best of times and the worst of times. Everyday life in the United States is physically easy. Women do not die in their twenties during childbirth or spend most of their waking hours cooking and cleaning. Men do not die in their thirties and forties from physical accidents during work or from exhaustion. On the contrary, we have a great deal of leisure time and we use it to travel and entertain ourselves. As for myself, a woman of modest origins and middle age, I have had the joy of devoting my life to exactly what intrigues me most—the workings of the natural world. Not only can I spend my time following my curiosity where it may lead, I get paid well for doing so. I live close to Rocky Mountain National Park, one of the country’s premier natural areas, which has recently celebrated a century of national park status. This is the best of times.

My curiosity has led me into places I never imagined when I started my scientific journeys. I set out to study remote mountain streams in Rocky Mountain National Park, unaware that the top aquatic predator had been fished nearly to extinction and replaced by introduced species. I mapped dozens of logjams in old-growth forest streams, not suspecting the critical role the jams played in retaining nitrogen in an ecosystem being gradually overwhelmed by atmospheric nitrogen inputs from feedlots and tailpipes. I measured peak snowmelt flows, ignorant of the steadily earlier occurrence of these flows each spring as warming climate and windblown dust rushed the snows from the hills. As I learned more about how people are driving environmental change in the national park, I struggled with the weight and responsibilities of the new knowledge. We like to refer to early signs of change as a canary in the coal mine. As one of my colleagues in the climate science community noted, canaries in the coal mine were brought down to die first. This is the worst of times.

In various ways, we each choose a path that reflects the luxuries and indulgences of the best of times, and the responsibilities and urgencies of the worst of times. This book is a collection of personal reflections on our early twenty-first-century times in the context of Rocky Mountain National Park, and an exploration of what makes our times good and bad. I enter the national park as someone who seeks rejuvenation in the natural world. I cannot go too long without spending time in some natural area or something inside me starts to wither. I also perceive the park as a geologist who studies river processes. When I think of the park, I think of a massive block of hard bedrock. The rock has been thrust up from Earth’s interior, cooled, and cracked. Gouged by glacial ice, chipped at by freezing and thawing, creased by water, the rock nonetheless remains dominant. Water pools in the depressions and plants are sprinkled lightly over the rock, able to maintain only the shallowest roothold. A strong wind, a heavy rain, or a fire, and the plants are instantly stripped away, their successors left to laboriously regrow over succeeding decades. As a bumper sticker popular with geologists proclaims, “It’s all about geology.”

My perceptions of the park reflect what I directly experience, what I learn through my research, and what I read. By all of these pathways, I have come to understand that even a national park is marked by the lingering effects of people using this ecosystem over the past two centuries. This is the most difficult lesson to assimilate, for I always want to look at an alpine lake or a ribbon of white water twisting down a rock face and simply appreciate the beauty. Remembering that the lake is slowly acidifying and the white water will dry up earlier in summer than during the past does not diminish the beauty of what I see, but adds an undertone of responsibility for acting to understand and to limit these human-caused changes.

I also think of the park as a much wetter place than it really is, because I work in the wet parts. The scarcity of water in Rocky Mountain National Park defines the rate at which soils form, the types of plants and animals present, and the pace of landscape change. More abundant water, whether over tens of thousands of years during which glaciers advance, or a few days during which streams flood, drives periods of landscape change.

Varying paces of change in the park led me to structure this book around the theme of rhythms. Like any plant or animal in the park, I live my life in annual rhythms based on the weather of each season, but also, in my case, on the academic calendar. I am a professor on the faculty of Colorado State University, with classes to teach during the academic year. Long, physically strenuous days of summer field research alternate with the desk days of winter, when I try to organize and understand the crowded observations of the field season and communicate some of that understanding to my students. The academic year tracks the seasonal year with fall and spring semesters and summer break.

Rhythms in Rocky Mountain National Park over longer time spans are less regular and predictable. Fires spread out from a lightning strike and alter the forest in which I work in ways that will persist for more than a century. Torrential summer rains strip soil and trees from the hillslopes and send streams flooding across the valley bottoms, creating alluvial fans that persist for many centuries. Glaciers advance and retreat over tens of thousands of years. Tectonic energy raises mountains and erosion wears them down over millions of years. These rhythms are punctuated with large changes in a short period of time. Punctuated rhythms create unpredictability. Are we on the cusp of big changes? It’s hard to know. Our understanding of climate warming, for example, is a moving target that keeps changing, partly in response to the greenhouse gases we continue to put into the atmosphere and partly because of our limited understanding of exactly how those gases will influence the complicated feedbacks that interact to create climate. People pin their hopes on environmental resilience—the ability of natural systems to absorb change and keep functioning. We also need resilience of people and institutions to help environments remain resilient.

The hundredth anniversary of Rocky Mountain National Park presented an opportunity to contemplate how the natural and human history of the park has shaped present ecosystems and how the varying rhythms of geology, climate, plants and animals, and people have shaped the national park. This book is structured around the seasonal rhythm of a calendar year, but in the chapter for each month I explore some aspect of other longer and shorter rhythms of natural and human history, focusing on a particular place within the park that somehow exemplifies such history.

At least two themes emerge repeatedly in these explorations. The first is the fundamental unevenness of change. Whether considered under the detailed focus of a single year or the grand sweep of millennia, many of the changes in topography and plant and animal communities in the national park take place during a relatively small portion of the time being considered. The rainfall spread over two to three days in September 2013 brought thousands of cubic yards of sediment from steep hillslopes down into valley bottoms. No such large and widespread debris flows had occurred in the park for decades before 2013. Analogously, subsequent geologic processes have barely modified the topography left by glaciers that carved steep-sided troughs into the spine of the continental divide more than 10,000 years ago. Some of the high-elevation forests in which I work have just begun to grow trees as tall as I am more than thirty years after a wildfire. Recognizing the unevenness of changes in natural landscapes and ecosystems through time and across space is critical to understanding how the natural world of Rocky Mountain National Park operates and to managing the national park toward desired conditions. In this book, I explore the causes and consequences of unevenness of change.

The second theme that emerges in exploring the natural communities of the national park is the importance of the unseen. The diverted water that flows far beneath the park in a tunnel, and the invisible dust particles that bring nitrogen to the soil and water of the park, create important and persistent changes, of which most park visitors remain unaware. Introduction of exotic species of trout has resulted in changes among the microscopic aquatic insects of subalpine lakes and streams, a historic shift completely unknown to nearly all park visitors, yet a change with potentially important consequences for freshwater ecosystems. With awareness comes insight about the effects of our own choices, and responsibility to choose wisely to best preserve the park that we care about, so I also explore the causes and consequences of unseen changes within the national park.

An iconic Rocky Mountain National Park view: Hallett Peak and the continental divide from Sprague Lake.

There is an old curse, “May you live in interesting times.” We do. That is our burden, and our opportunity. We can respond effectively to burden and opportunity only if our actions grow from understanding of how natural forces and human actions have shaped the topography and plant and animal communities of the national park. In this book I systematically examine how the natural forces of geology, climate, fire, and interactions among plants and animals have shaped and continue to shape Rocky Mountain National Park. Although the majority of the national park is designated as wilderness, every portion of the park also reflects the influence of human activities, even if this imprint is largely invisible. Consequently, I also systematically explore how historical mining, logging, ranching, tourism, and removal of predators, along with contemporary warming climate, air pollution, fire management, and encroachment of urban areas have shaped and continue to shape the national park. Each of the succeeding chapters focuses on a particular type of natural or human influence on the park and the time and space scales—the rhythms—over which that influence is exerted, but each chapter also reflects the complex interactions among natural and human influences.