Laguna Canyon Biological Resources Inventory
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LAGUNA CANYON BIOLOGICAL- RESOURCES INVENTORY Prepared for the City of Laguna Beach, California By Karlin G. Marsh, Biological Consultant With Contributions by James Pike, Consulting Ornithologist May 28, 1993 Karlin C. Marsh Biological Consultant ~~~amtmre;-Pre.X-464;SitWra~fatifmia926-76 7W9.3829 Rural Route 1, Box 958, Meadville, Pennsylvania 16335 (814) 333-2016 LAGUNA CANYON BIOLOGICAL RESOURCES INVENTORY Prepared for the City of Laguna Beach, California By Karlin G. Marsh, Biological Consultant Rural Route 1, Box 958 Meadville, Pennsylvania 16335 (814) 333-2016 Contributions by James Pike, Consulting Ornithologist 18744 Beach Blvd., Dpx. E Huntington Beach, California 92648 (714) 968-7977 May 28, 1993 TABLE OF CONTENTS PAGE INTRODUCTION ...................................... 1 PURPOSE OF STUDY ..................................... 1 1.1.1 History of City Resource Inventory Work ...... 1.1.2 What Lies Ahead .............................. 2 1.1.3 Objectives ......................... .......... 4 PHYSICAL SETTING .................................... 4 1.2.1 Area of Survey ............................... 4 1.2.2 Topography and Hydrology..................... 5 1. Hydrology................................ 5 2 . Topography............................... 7 1.2.3 Geology ...................................... 7 1.2.4 Soils ........................................ 8 PRIOR INVENTORIES ................................... 9 1.3.1 Laguna Canyon ................................ 9 1.3.2 Laguna Heights............................... 11 1.3.3 General ...................................... 13 METHODS ............................................. 14 BIOLOGICAL SETTING ................................ 16 BIOTIC COMMUNITIES .................................. 18 Venturan-Diegan Transitional Coastal Sage Scrub ..... 18 Southern Cactus Scrub ............................... 20 Cha arral ....................................... 21 hrass ands .......................................... 23 lernal Pools. Seeps and Wet Meadows ................. 26 Riparian Habitats ................................. 28 Coast Live Oak Woodland ............................. 33 Cliff and Rock Habitats............................. 36 Watercourses ........................................ 40 A riculture......................................... 41 I+---eve oped Areas. Disturbed.......................... 41 TABLE OF CONTENTS (Cont'd) -PAGE 2.2 SITE DESCRIPTION................................... 2.2.1 Laguna Canyon From Big Bend to City Dump. ... 1. Big Bend................................ 2. Ravine Two.............................. 3. Ravine Three............................ 4. Castlerock Ravine....................... 5. Hillside Between Castlerock Drive and Old City Dump......................... Stan Oaks Ravine Raquel Ravine G.T.E, Facility 2.2.2 DeWitt Parcel and Adjacent Portions of Laguna Canyon-. and Aliso and Wood Canyons Regional -Park......................................... 1. Laguna Canyon Floor...................... Sun Valley..... ...................... DeWitt Panhandle..................... Stoneridge Riding Club............... Annelieses's Preschool............... Upstream Reach of Lower Laguna Creek Wildlife of Laguna Creek............. 2. Laguna Canyon Slope...................... Water Tank Ravine.................... South Ravines........,............... Stans Lane Ravine.................. Dump Ravine........................ 3. DeWitt Ridge............................. of Wood Canyon..................... 4. Wood Canyon...........................*.. West Headwater Branch................ Main Stem of Wood Canyon............. 2.2.3 Laguna Heights....................*.......... 1. Ridgeline................................ Main Ridge................*.......... Mathis Grade......................... TABLE OF CONTENTS (Cont'd) PAGE 2. South Branch. Mathis Canyon ............. 94 3. North Branch. Mathis Canyon ............. 102 2.3 WILDLIFE ......................................... 107 2.3.1 -Fish....................................... 107 2.3.2 Amphibians .............................. 107 2.3.3 Reptiles ................................... 107 2.3.4 Birds ....................................... 108 2.3.5 Mammals ................................. 113 1. Marsupials.............................. 113 2. Insectivores............................ 113 3. Bats .................................... 113 4. Lagomorphs .............................. 114 5. Rodents ................................. 114 6. Carnivores .............................. 115 7 . Hoofed Animals .......................... 116 2.4 SENSITIVE BIOTA AND HABITATS ....................... 117 3.0 RESOURCE MANAGEMENT RECOMMENDATIONS ................ 138 3.1 DEVELOPMENT GUIDELINES IN LAGUNA CANYON ............. 138 3.2 LAGUNA CREEK FLOOD CONTROL AND WATER QUALITY IMPROVEMENT ......................................... 142 3.2.1 Flood Control ................................ 142 3.3 UTILITY AND PATROL ACCESS ........................... 144 3.4 REVEGETATION AND WEED CONTROL ....................... 145 3.5 LAGUNA CANYON ROAD .................................. 147 3.6 RECREATIONAL USE .................................... 150 3.6.1 Avoiding Impact to Raptors and Mule Deer ..... 150 3.6.2 Avoiding Impact to Rare Plant Populations and Sensitive Avifauna and Reptiles.......... 153 3.6.3 Monitoring................................... 154 TABLE OF CONTENTS (Cont'd) PAGE 4.0 APPENDIX ............................................ 156 4.1 SPECIES LIST ........................................ 156 4.1.1 Native and Naturalized Plants................ 156 4.1.2 Selected Ornamentals ......................... 178 4.1.3 Vertebrate Fauna ............................. 187 4.2 REFERENCES .......................................... 198 4.2.1 Persons and Organizations Consulted.......... 198 4.2.2 Bibliography................................. 199 1.0 INTRODUCTION This is a biological resource inventory of open space between Laguna Canyon Road from El Toro Road south to Big Bend, and Aliso and Wood Canyon Regional Park. It encompasses Laguna Canyon prop- erties and the DeWitt and Laguna Heights land blocks. 1.1 PURPOSE AND SCOPE OF STUDY 1.1.1 History of City Resource Inventory Work This biological study of the east Laguna Canyon area has been prepared at the request of the City of Laguna Beach to complete the inventory process on all open spaces of substantive size within its corporate boundaries. This is probably the final report of a series begun in 1983 encom- passing open spaces within the following land blocks: "Old City" (1983) Sycamore Hills (1983) South Laguna (1992) Laguna Canyon (1993) Two other regions of the City containing open space are the beachfront, including the marine, littoral and some undeveloped uplands beyond tidal reach, and the long, narrow strip of incorporated land on the Irvine Ranch immediately west of Laguna Canyon Road. The author con- ducted a beachfront field survey of upland parcels only in 1983 but did not complete an assessment report because funding had been exhausted on the "Old City" and Sycamore Hills inventories. Significant findings of the beachfront survey were: m Discovery of a range extension-population of Dudleya caespitosa, so called "sea lettuce", on the cliffs at Irvine Cove. Location of a single vacant seafront land parcel south of Main Beach containing the regionally depleted coastal bluff scrub plant community. 0 Conclusion that indigenous seacliff rupicoles had been largely replaced by exotic succulents widely introduced as the oceanfront was developed. The community of Emerald Bay refused access to conduct inventories within its inholding. The lands on the west side of Laguna Canyon Road have not been surveyed by the author. Until recently, the Irvine Co. was reluctant to allow access by city consultant per- sonnel for this purpose. The author accompanied CALTRANS personnel during a brief focused survey for rare plant species between Laurel Canyon and Big Bend. A number of stands of many-stemmed dudleya (Dudleya multicaulis) were mapped within the area of potential effect of a widened Laguna Canyon Road, Nearby, near the mouth of Laurel Canyon, the author and others accompanied Dudleya expert Reid tioran (formerly curator of the San Diego Natural His- tory Museum Herbarium and describer of many dudleya spec- ies, including D. stolonifera) in an inspection of the Laurel Canyon ~aguna Beach dudleya (L stolonifera) colony. Later, she took CA Fish and Game Natural Diversity Data Base/Natural Heritage botanist Susan Cochrane to the site. State endangered species funds subsequently helped protect this beautiful area. Some of the tributary canyons on the west side of Laguna Canyon Road in addition to Laurel were subject to an older survey for Orange County Flood Control which was quite com- prehensive in scope (Marsh, G.A. and P.Y. OIBrien, 1974; see Section 1.3). Feldmuth and Associates and the Chambers Group have surveyed lands within the Laguna Laurel project area. A study of the Laguna Lakes is in progress at this time by Wetlands Research Associates. The Nature Conser- vancy is to conduct studies throughout open space setasides of The Irvine Co., presumably including those which bound Laguna Canyon. Finally, a comprehensive General Development Plan for the entire Laguna Coast Wilderness Park, to be commenced in 1993 will presumably include biological re- source inventories and a Resource Management Plan focused on protecting key habitats and wildlife dispersion corri- dors in an outdoor recreational