ABSTRACT DEVELOPMENT AND APPLICATION OF A GEOSPATIAL DATABASE OF SIERRA NEVADA LAKES AND RESERVOIRS by Molly Gail Mehling High-elevation, mountain regions, such as the Sierra Nevada, are characterized as extremely heterogeneous and ecologically fragile. The Sierra Nevada has been recognized for its high conservation value, but historical and predicted tourism and development threaten the ecological resources of the region. Assessment and monitoring of the Sierra Nevada’s aquatic resources and their catchments is crucial to their balanced management. Using a digital geospatial database, landscape-scale variables of morphometry, land cover and human activities were quantified for 20 assessment sites and their catchments in the most rapidly developing area of the ecoregion, the central Sierra Nevada. Landscape-scale variables revealed ecological and anthropogenic heterogeneity among the sites. These measurements were incorporated into a multi-level index of ecological integrity and were analyzed with multivariate statistical methods to objectively assess similarity among sites. It is expected that these metrics will be incorporated into a multi-level assessment protocol. DEVELOPMENT AND APPLICATION OF A GEOSPATIAL DATABASE OF SIERRA NEVADA LAKES AND RESERVOIRS A Practicum Report Submitted to the Faculty of Miami University In partial fulfillment of the Requirements for the degree of Master of Environmental Science Institute of Environmental Sciences By Molly Gail Mehling Miami University Oxford, Ohio 2006 Advisor: ____________________ Dr. James Oris Reader: ___________________ Dr. Gene Willeke Reader: ______________________ Dr. William Renwick TABLE OF CONTENTS Table of Contents ...............................................................................................................ii List of Figures .....................................................................................................................iii List of Tables ......................................................................................................................iv List of Plates.........................................................................................................................v Acknowledgments..............................................................................................................vi Chapter 1: Introduction.....................................................................................................1 Chapter 2: Assessment Site Descriptions......................................................................6 Chapter 3: Development of a Geospatial Database..................................................21 Chapter 4: Quantification of Landscape-scale Characteristics................................25 Chapter 5: Application of Landscape-scale Characteristics.....................................45 Chapter 6: Conclusions ...................................................................................................52 Literature Cited .................................................................................................................54 ii LIST OF FIGURES Figure Page 1. Locations of assessment sites ......................................................................7 2. Examples of varying degrees of shoreline development..........................29 3. Index of ecological integrity ......................................................................47 ii i LIST OF TABLES Table Page 1. General descriptive characteristics of assessment sites................................8 2. GIS layers and their respective sources .....................................................24 3. Ecological characteristics of assessment sites.............................................33 4. Relative percentages of USGS NLCD 1992 land cover classes ...............36 5. Human activity within assessment site catchments....................................39 6. Variable groups and variables for multi-level index of ecological integrity .....................................................................................................46 7. Rescaled PCA eigenvectors for morphological, land cover, and human activity comparison ......................................................................49 iv LIST OF PLATES Plate Page 1. Upper Angora Lake .....................................................................................9 2. Donner Lake ..............................................................................................12 3. Eagle Lake ..................................................................................................13 4. Sand Harbor, Lake Tahoe.........................................................................15 5. Marlette Lake..............................................................................................17 6. Spaulding Reservoir....................................................................................18 7. Stampede Reservoir ...................................................................................19 8. Tahoe Keys, Lake Tahoe: Shoreline Development.................................42 v ACKNOWLEDGMENTS It is a pleasure to thank the many people who inspired, supported and assisted me on the path to my practicum’s completion. It is difficult to overstate my gratitude to my adviser, Dr. James Oris, for this opportunity. With his patience and guidance I was able to refine many skills and develop novel ones while contributing to a valuable research project. I must also extend sincere gratitude to Dr. Avram Primack who provided me with GIS shortcuts and suggestions throughout the project. I am indebted to my many student colleagues for providing a stimulating and fun environment in which to learn and grow. Collaboration with Carrie Smith and Scott McClain enhanced this research significantly. I am especially grateful to Tom Arbour, Dana Thomas, and Nathan Moyer for many hours of intellectually stimulating discussions. Lastly, I’d like to thank my husband, Los, for his selfless contributions to this practicum. I am not only eternally grateful for his support of my career, but for the many mind-bending conversations about tourism and the environment. I look forward to our collaborations, both personal and professional. I am extremely grateful to be a part of the Miami University Institute of Environmental Sciences (IES) family. Drs. Gene Willeke, Sandy Woy-Hazelton, and Vincent Hand have always been intrigued and supportive of my research endeavors providing valuable constructive criticism along every step of the way. IES has provided me with the strongest of foundations on which to build my environmental career. I will always be grateful for the interdisciplinary, collaborative, problem- solving framework in which I was trained. I dedicate this practicum to my IES mentors. vi Chapter 1 INTRODUCTION SIERRA NEVADA ECOREGION The Sierra Nevada, located in the western United States, is the longest, unbroken chain of mountains in North America, spanning 400 miles north to south. Recreational opportunities and breath-taking scenery attract tourists year round as well as an ever-increasing population of permanent residents. Between 1970 and 1990, the human population in the Sierra Nevada doubled from 300,000 to 650,000, most of which was concentrated in three counties (Nevada, Placer, and El Dorado) (Davis, 1996). The population is expected to reach nearly 2 million by 2040. The growing population has not come without taking an ecological toll on the region. One of the most publicized of these impacts is the eutrophication of Lake Tahoe. Lake Tahoe, one the nation’s largest, clearest, and deepest lakes, is the most popular natural attraction of the Sierra Nevada. However, over the last 50 years a measured loss of water clarity has sparked concern among stakeholders, those parties interested in the condition and fate of Lake Tahoe (Goldman, 1988; Tarnay et al., 2001). The Sierra Nevada ecoregion, once thought to be pristine, is now recognized for its fragility. A thorough environmental assessment of the ecoregion, the Sierra Nevada Ecosystem Project (SNEP), was conducted in the mid 1990s, and a comprehensive report was submitted to Congress in 1996 (Davis, 1996). In 1997, the Lake Tahoe Presidential Forum was held in Incline Village, NV. At the forum, President Clinton pledged $50 million to protect and restore Lake Tahoe and its basin. The region is also recognized by the World Wildlife Fund as a “globally outstanding ecoregion requiring immediate protection or restoration” (Ricketts et al., 1999). More recently, the United Nations designated 2002 as the International Year of Mountains to celebrate and bring recognition to the world’s ecologically and culturally diverse 1 regions. A result of this recognition prompted the completion of the first Mountain Watch report, completed by the United Nations Environment Programme (UNEP) and many partners (2002). The report identifies three mountainous areas of particular concern for global conservation based on high biodiversity and severe environmental pressures. One of those areas was the montane ecoregions of California (UNEP et al., 2002: 8) and the other two regions identified were the North-Western Andean moist forest and Magdeleña Valley of South America and the Caucasus mixed forests ecoregion. High-elevation, mountainous regions, such as the Sierra Nevada, are characterized as extremely spatially heterogeneous, high in biodiversity, relatively low in productivity, and particularly