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CALIFORNIA STATE UNIVERSITY, NORTHRIDGE HABITAT SUITABILITY ANALYSIS OF THE COAST HORNED LIZARD (PHRYNOSOMA CORONATUM BLAINVILLII) IN THE SANTA MONICA MOUNTAIN NATIONAL RECREATION AREA A thesis submitted in partial fulfillment of the requirements For the degree of Master of Arts in Geography By Eryn Morrigan May 2013 The thesis of Eryn Morrigan is approved: Shawna Dark, Ph.D. Date Yifei Sun, Ph.D. Date James Hayes, Ph.D., Chair Date California State University, Northridge ! ii! DEDICATIONS This thesis is dedicated to: Ryan Morrigan “For small creatures such as we, the vastness is bearable only through love.” - Carl Sagan Exzelia “Zell” Butler “…The grey rain-curtain turned all to silver glass and was rolled back, and [s]he beheld white shores and beyond them a far green country under a swift sunrise." - Gandalf ! iii! ACKNOWLEDGMENTS I would like to first acknowledge my committee chair, Dr. James Hayes, for his guidance and support in this research. I deeply appreciate your patience as my advisor, your feedback on my thesis as well as in the classes I was privileged enough to have with you, and your advice for the future. To my committee members, Dr. Shawna Dark and Dr. Yifei Sun, thank you for reading my drafts and providing feedback. I am very fortunate to have had your advice and support in this process. To Dr. Soheil Boroushaki, thank you for helping me transform my data into an interactive web-based map as part of my portfolio. Personally, I would like to thank Christopher Schultz for reading my thesis, but most importantly his indomitable sense of optimism even in the darkest and longest of days. And finally, the Coast Horned Lizard for being such an irresistible and fascinating organism to study. May your species inspire others to respect and protect all the wonders of life on our fragile planet. ! iv! TABLE OF CONTENTS Signature Page ii Dedications iii Acknowledgment iv List of Figures vii List of Tables viii Abstract ix 1.0 INTRODUCTION 1 1.1 Purpose 2 1.2 Objectives and Research Questions 4 2.0 STUDY AREA 8 2.1 Flora 9 2.2 Fauna 11 2.3 Climate 14 3.0 COAST HORNED LIZARD ECOLOGY AND CONSERVATION 15 3.1 Coast Horned Lizard Distribution and Ecological Suitability 15 3.2 Modern Conservation Concerns for Coast Horned Lizards 18 3.3 Horned Lizards and Prey 20 3.4 Horned Lizard Habitat Issues 23 4.0 METHODOLOGY 27 4.1 Data Sources and Limitations 27 4.2 Mapping Techniques 31 4.3 Classification of Suitability 33 4.3.1 Vegetation Classification 34 4.3.2 Soil Classification 36 4.3.3 Slope and Border Classification 39 4.4 Reclassification 41 4.4.1 Vegetation 41 4.4.2 Soil 46 4.4.3 Slope 51 4.4.4 Border 55 4.5 Landscape Metrics 57 5.0 RESULTS 64 5.1 Expectations 64 5.2 Suitability Models 65 5.2.1 Suitability Model 1 67 5.2.2 Suitability Model 2 71 5.2.3 Suitability Model 3 75 5.3 Metrics 79 5.3.1 Suitability Model 1 Metrics 79 ! v! 5.3.2 Suitability Model 2 Metrics 80 5.3.3 Suitability Model 3 Metrics 81 6.0 DISCUSSION 83 6.1 Metrics and Patterns 83 6.2 Research Question 1 86 6.3 Research Question 2 87 6.4 Research Question 3 89 7.0 CONCLUSION 92 7.1 Limitations 92 7.2 Impact on Future Research 94 REFERENCES 96 APPENDIX A 109 APPENDIX B 111 APPENDIX C 112 ! vi! LIST OF FIGURES Figure 1 - Official Map of SMMNRA 8 Figure 2 - SMMNRA Border and Coast Horned Lizard Range 9 Figure 3 - Coast Horned Lizard, Los Angeles County 17 Figure 4 - Juvenile Coast Horned Lizard, Los Angeles County 18 Figure 5 - CHL Habitat Example, San Gabriel Mountains 25 Figure 6 – CHL Habitat Example, San Bernardino Mountains 25 Figure 7 - Original Vegetation Map 44 Figure 8 - Reclassified Vegetation Map 45 Figure 9 - Original Soil Series Map 49 Figure 10 - Reclassified Soil Series Map 50 Figure 11 - Original Slope Percent Map 53 Figure 12 - Reclassified Slope Percent Map 54 Figure 13 - Original SMMNRA Buffer Map 56 Figure 14 - Reclassified SMMNRA Buffer Map 56 Figure 15 - Map of the Four Major Identified HSAs in SMMNRA 66 Figure 16 – Suitability Model 1 70 Figure 17 – Suitability Model 2 74 Figure 18 – Suitability Model 3 78 ! vii! LIST OF TABLES Table 1 - Vegetation Type Classification Table 36 Table 2 - Soil Type Classification Table 37 Table 3 - Slope and Border Type Classification Table 40 Table 4 - Approximate Landmark Boundaries of the Four Identified HSAs 65 Table 5 – Suitability Model 1 Total Area Type Percent 69 Table 6 – Suitability Model 2 Total Area Type Percent 73 Table 7 – Suitability Model 3 Total Area Type Percent 77 Table 8 – Model 1 Metrics 80 Table 9 – Model 2 Metrics 81 Table 10 – Model 3 Metrics 82 Table 11 – Weighting and HSA/HMSA Results Comparison 85 ! viii! ABSTRACT HABITAT SUITABILITY ANALYSIS OF THE COAST HORNED LIZARD (PHRYNOSOMA CORONATUM BLAINVILLII) IN THE SANTA MONICA MOUNTAIN NATIONAL RECREATION AREA by Eryn Morrigan Master of Arts in Geography The Coast Horned Lizard (Phrynosoma coronatum blainvillii) is a native species of special concern in California. One of the major threats to Coast Horned Lizards, particularly in southern California, is habitat loss and fragmentation. Studies have suggested that the Coast Horned Lizard selects habitats in chaparral and coastal sage scrub vegetation with friable sandy soils and low to moderate slope percent rise. The Santa Monica Mountains National Recreation Area (SMMNRA), located in Los Angeles and Ventura counties, is within the known range of Coast Horned Lizard inhabitation. Due to ecologically disruptive human activity in and around the SMMNRA, potential Coast Horned Lizard highly suitable habitat may be at risk of fragmentation, decrease in suitability and/or complete loss of habitat. This study identifies areas of high Coast Horned Lizard suitability so that these areas may be further studied in regards to actual species presence and human impact. Habitat suitability models and landscape pattern were analyzed to investigate the extent to which the SMMNRA is suitable for Coast ! ix! Horned Lizard inhabitation. First, three habitat suitability models were used to classify the habitat suitability of areas in the SMMNRA depending on designated habitat needs such as slope, soil type, and vegetation cover. Then landscape metrics were used to measure habitat fragmentation, particularly for highly suitable areas. In the SMMNRA, 70% of the total land area was found to meet the majority of the habitat suitability criteria (high suitability, HSA) or some of these requirements (high-medium suitability, HMSA) for the Coast Horned Lizard. HMSAs covered from 59% to 66% of the SMMNRA, depending on the model’s weighting. Similarities in percent areas were observed between the results for model 1 and model 3. Model 2 showed significantly higher HSA percent (11%) than other models (3%) due to increased vegetation weighting. The landscape patterns and metrics of the SMMNRA showed that most of the area is at least HMSA for Coast Horned Lizards. Fragmentation occurred in areas of human impact but did not prevent the connection of suitable habitats within the interior mountain range. Other factors of suitability should be explored in respect to the SMMNRA to gain a more accurate assessment of Coast Horned Lizard habitat. In addition, field surveys would be needed to confirm actual Coast Horned Lizard presence ! x! 1.0 - INTRODUCTION Mediterranean ecosystems have been highly favored and impacted by humans for habitation, agriculture and recreation. These rare and very biodiverse ecosystems compose roughly two percent of the Earth’s land area, are highly altered by human activities, often contain major cities, and have little undisturbed area (Swenson and Franklin 2000). Southern California has been identified as a Mediterranean ecosystem and a biodiversity hotspot due to the unique flora and fauna present, even though it is highly impacted by humans for development, housing and transportation. The high degree of urbanization along the southern California coastline has resulted in the loss of significant wildlife habitat and the fragmentation of naturally occurring biological corridors (National Park Service 2012 “Climate”). Habitat fragmentation is the leading factor in species loss both locally and globally (Wilcox and Murphy 1985). It can be caused by increasing the number of habitat patches, decreasing interior habitat area, and increasing the extent of landscape edges or increasing isolation of habitat patches (Li et al. 1993). Birds and mammals are often the first to be affected by habitat fragmentation due to their large ranges, resulting in a decrease in population viability from limited mate selection ranges (Beier 1993). Reptiles and small mammals with limited mobility may be separated into distinct populations due to narrow geographic barriers such as intervening roads and borders that smaller species cannot bypass (Quinn 1990). Urban development is an important environmental factor because it creates highly modified landscapes that show higher rates of invasive, non-native, and disturbed ! 1! vegetation (Swenson and Franklin 2000; Endriss et al 2007). Urban modified landscapes often contain small, isolated patches of native vegetation also inhabited by greatly altered flora and fauna. Urbanization affects the physical structure and species composition of native vegetation in many ways, including replacement of native vegetation with invasive or non-native species, soil compaction, changes in microclimates, and isolation of undeveloped native habitat remnants (Endriss et al 2007). Urban development also often involves the increasing encroachment of roads and structures into non-developed land. One inhabitant of the California Mediterranean ecosystem zone is the Coast Horned Lizard, Phrynosoma coronatum blainvillii. The Coast Horned Lizard (CHL) is a specialist species in regards to both habitat and prey.