CHAPTER TWO A CONTEXTUAL OVERVIEW OF HUMAN LAND USE AND ENVIRONMENTAL C ONDITIONS Susan Lindström with contributions from Penny Rucks and Peter Wigand ©1999 J.T. Ravizé. All rights reserved. CHAPTER TWO A CONTEXTUAL OVERVIEW OF HUMAN LAND USE AND ENVIRONMENTAL CONDITIONS Susan Lindström with contributions from Penny Rucks and Peter Wigand Introduction the public’s perception of one. With this latest shift The Lake Tahoe basin embodies the in land use paradigms, the direction of progress for consequences of a long legacy of human and 21st century users of the Tahoe basin is less clear. In environmental history. Here, human land this fragile context, the Lake Tahoe environment is disturbances were initiated by millennia of low- becoming intensively managed, partly based on intensity land management by the Washoe Indians scientific research findings, such as those contained and their prehistoric predecessors. Within a century’s in this assessment of the Lake Tahoe watershed. time, indigenous practices were replaced by Human beings have been a component of profound resource exploitation by incoming Euro- the Lake Tahoe ecosystem for at least 8,000 to 9,000 American populations. During the last few decades, years. Contemporary land management efforts to agency regulation has struggled to control explosive restore the Lake Tahoe ecosystem benefit from an community growth induced by millions of tourists understanding of the long-term ecological role of who visit the Lake Tahoe basin each year. aboriginal people and Euro-American settlers in the Changing attitudes and assumptions about dynamics of wild plant and animal populations and Tahoe’s environment have both enshrined and their physical environments. Past land management desecrated its landscape. Native Americans practices engendered environmental impacts that considered themselves stewards of the land and vary in space, time, scale, intensity, and consequence. sustained a balanced relationship between human Human disturbances range widely in scale, from society and the environment. Nineteenth century pruning a patch of native shrubs to clear-cutting arrivals viewed the Tahoe basin as a natural setting thousands of acres of timberland. Some resources for Comstock-era capital investment and profit. were targeted in a single brief event, while others Devastating practices, such as clear-cutting forests, were affected for decades or generations. were acclaimed by a society that celebrated human Furthermore, prehistoric and historic impacts may conquest of nature as progress. During the 20th not have extended basin-wide, and some areas may century, the emerging dominance of the tourism have been relatively unaffected. industry was accompanied by a growing awareness In order to shape an approach to ecosystem of resource protection rather than resource planning and resource management in the Tahoe extraction. However, the environmental pressure of basin, we ask a number of key questions regarding large numbers of tourists and the growing residential the physical and cultural conditions that existed in population that serves them has transformed the the past and the scope and scale of anthropogenic, Tahoe basin into a landscape that is, paradoxically, or human-induced, disturbances that have altered increasingly imperiled by its own attractiveness these conditions: (Elliott-Fisk et al. 1997; Raymond 1992). Tahoe’s • How have climate changes affected changes future well-being depends directly on a healthy in Tahoe’s overall physical and cultural physical and socioeconomic environment, not only environment? Under varying climatic Lake Tahoe Watershed Assessment 23 Chapter 2 regimes, what sustainable environmental single source of information by itself. conditions are possible in the future and To document human disturbances and what type and scale of management environmental conditions of the Lake Tahoe treatments would be required to achieve landscape and to register the changing human them? perceptions surrounding them through time, this • What did pre-Euro-American terrestrial and contextual discussion draws on the existing aquatic ecosystems look like, and how have literature, supplemented by personal notes and prehistoric and historic anthropogenic experience. The overview is far from exhaustive and disturbances affected changes in plant and data are uneven. Assembled at an earlier time and for animal communities? a different purpose, data are adapted to fit into the • What were the prehistoric and historic fire current watershed assessment context; yet, the regimes in the Lake Tahoe basin? context is intended to be interpretive and • What are the past and present sources of comparative, beyond merely descriptive. Integral sediment and nutrients in Tahoe’s historic descriptions are dispatched to the summary watershed that affect water quality? time lines at the end of this chapter. Important environmental issues and questions involving biotic • How has air quality and atmospheric health, air and water quality, and socioeconomic visibility changed from prehistoric to well-being, topics that are fully explored in present times? • subsequent chapters, are introduced here to provide What are the historic underpinnings of historical perspective. The deliberate incorporation causal relationships among the many of paleoenvironmental, archaeological, ethnographic, socioeconomic and environmental factors and historical data into truly multidisciplinary in the Tahoe basin? environmental planning efforts treads untested • What are the culturally important locales ground. Yet, in the context of ecosystem and biotic species in the basin and what are management, these lines of inquiry reveal the the threats to these resources? considerable extent to which cultural and To answer these and other questions and to environmental history can effectively guide future establish standards by which environmental health management. and socioeconomic health can be measured, historical data sources that are uniquely tied to the Paleoclimate and Environmental History human dimension of the ecosystem are explored, together with input from the biological, hydrological, Environmental Change in the Tahoe Sierra and atmospheric sciences. History directs future decision-making by setting a baseline of reference The resolution of fundamental issues conditions to determine how present conditions concerning the nature and timing of cultural- differ from past conditions, the reasons for that environmental associations has been influenced by difference, and what sustainable conditions may be the three-part model of climatic change for the possible in the future. With knowledge of how past 10,000-year Holocene period (Antevs 1925; Davis peoples interacted with their landscape, scientists 1982). Antevs (1925) subdivided this period into the and land managers can link this information to cool-moist Early Holocene, the hot-dry Middle restoration and maintenance of current ecosystems. Holocene, and the cool-moist Late Holocene. Paleoenvironmental, archaeological, ethnographic, Internal details of these periods are not without and historic documentation offer great time depth controversy, especially as they apply to the timing, and are used as independent and corroborative tools magnitude, and course of paleoenvironmental to achieve a nexus between historic conditions and change in western North America, in general, and contemporary research, monitoring, and adaptive the Tahoe Sierra, in particular. Although details of management. Thus, using multiple sources of Middle through Late Holocene climatic and information, it may be possible to achieve an ecosystem history are becoming much clearer in the understanding that would not be possible using a Great Basin to the east, within the Tahoe Sierra, 24 Lake Tahoe Watershed Assessment Chapter 2 current reconstructions lack resolution, and climatic among the few lakes that did not dry up completely. trends are necessarily presented as broad time Fossil pollen taken from Osgood Swamp (Adam brackets. Changing aspects of the natural 1967) and Little Valley in the Carson Range environment, which were of special importance to bordering the east side of Lake Tahoe (Wigand and human populations inhabiting the Tahoe Sierra Rhode 1999) indicates the presence of more during the last 9,000 years, are summarized below drought-tolerant species by the end of this period. and outlined in Table 2-1. Middle Holocene aridity in the Tahoe Sierra is further documented by the remains of submerged Early Holocene (10,000-7,000 Years Before Present) tree stumps, which stand rooted on the floor of Lake By the Early Holocene, warming and drying Tahoe, as deep as 20 feet below its present surface caused glaciers to recede and Lake Lahontan, which (Table 2-2; figures 2-2A and 2-2B). These ancient flooded much of the Great Basin, to shrink. drowned forests date from between 6300 and 4800 Although climates were relatively cool and moist BP (Lindström 1990, 1997). Shallowly submerged compared to those of today, they were considerably prehistoric milling features (bedrock mortars) occur warmer than those of the Late Pleistocene. Heavy lake-wide and may date from this or subsequent winter precipitation, which had characterized the droughts (Figure 2-3). About 5500 BP the harshest Late Pleistocene, continued during the Early period of Middle Holocene drought came to an Holocene. Pollen studies at Osgood Swamp near abrupt end, as manifested by the drowned shoreside Meyers at South Lake Tahoe (Adam 1967) indicate