Astragalus Pycnostachyus Var. Lanosissimus)
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ASSESSMENT OF EXPERIMENTAL OUTPLANTINGS OF THE ENDANGERED VENTURA MARSH MILKVETCH (ASTRAGALUS PYCNOSTACHYUS VAR. LANOSISSIMUS) Prepared by: Mary E. Meyer South Coast Region California Department of Fish and Game 4949 Viewridge Avenue San Diego, California 92123 November 30, 2007 For the California Department of Fish and Game and United States Fish and Wildlife Service Section 6 Contract E-2-P-22 ii Table of Contents Page I Executive Summary 1 II Project Overview and Current Status 3 Current Population Status 6 III Biology of Ventura Marsh Milkvetch 8 IV Approach and Methodology 19 2004 Plantings 20 Propagation 20 Site Selection 22 Installation 23 Maintenance 31 Monitoring the 2002 and 2004 Plantings 33 V Habitat Characteristics 33 General Habitat at the Wild Site 37 General Habitat at the Outplanting Sites 37 South Ormond Beach 37 Mandalay State Beach 39 McGrath State Beach 40 Carpinteria Salt Marsh Reserve 42 Coal Oil Point Reserve 44 VI Climate, Hydrology and Soils 50 Climate and Rainfall Patterns 50 Hydrology 56 Flooding and Inundation 56 Perched Water Tables 58 South Ormond Beach 59 Wild Site 60 Mandalay State Beach 61 McGrath State Beach 61 Carpinteria Salt Marsh Reserve 63 Coal Oil Point Reserve 63 Coal Oil Point Reserve - Lagoon 63 Coal Oil Point Reserve - Pond 64 Soils 64 VII Monitoring Results and Discussion 67 iii Original 2002 Outplants 67 Survivorship 67 Growth and Flowering 70 Flower and Fruit Production 75 Seed Production at Key Sites 78 2004 Supplemental Plantings 80 Survivorship 80 Growth and Flowering 84 Wild Site in 2006 89 Natural Recruitment 92 2003 Observations 99 2004 Observations 100 2005 Observations 101 2006 Observations 103 Comparison of First Year Natural Recruits 105 Seed Dormancy Observations 116 Seed Dispersal Observations 109 VIII Milkvetch Health and Diseases 113 Sudden Onset Decline in Full Flower on Whole Milkvetch Patch 113 Sudden Onset Decline in Full Flower on Single Individuals 115 Miniaturization 117 Spots and Weak Chlorophyll 117 Tissue Senescence and Blackening 118 IX Herbivory 119 Gastropod Herbivory 119 Snails 120 Snail Management 120 Slugs 121 Small Mammal Herbivory 121 Gophers 122 Rabbits 123 Herbivory Symptoms Attributed to Rabbits 124 Rabbit Herbivory Effects on Vegetation at Planting Sites 125 Vegetative Structure Favoring Rabbit Herbivory 126 Seasonal Variations in Rabbit Herbivory and Milkvetch Response 127 Rabbit Herbivory at the Wild Site 128 iv Meadow Voles 129 Ground Squirrels 130 Milkvetch Palatability and Selenium 130 Small Mammal Herbivory- Management Strategies 133 Chemical Herbivory Deterrents 133 Individual Caging of Milkvetch 133 Large Exclosures 134 Overgrowth of Vegetation in Cages and Exclosures 134 Duration of Caging and Exclosures 135 Disruption of Vole Runways 135 Arthropod Herbivory 135 Moth and Butterfly Caterpillars 135 Damage to Milkvetch 136 Seed Beetles 137 Aphids, Argentine Ants and Milkvetch 138 Other Argentine Ant Effects on Milkvetch 139 Management Recommendations for Argentine Ant Control 140 Isopod Herbivory 141 Management Response 141 Other Organisms Found under Isopod Traps 142 Other Animal Direct and Indirect Effects on Milkvetch 143 Moles 143 Skunks 143 X Associated Vegetation 144 Native and Naturalized Species 144 Non-Native Weeds 150 General Vegetation Trends across the Study Period 153 Seasonal Variation in Vegetative Cover 154 General Trends in Milkvetch and Vegetative Cover at Key Sites 155 Juvenile Establishment 157 Associated Vegetation at Poorly Performing Dry Sites 157 XI Recommendations for Future Modifications 160 Suggested Revisions to Methods and Protocols 160 Seed germination 160 Outplanting dates 160 Direct Seeding Trials 160 v Herbivory Exclosures 160 Planting Configuration 160 Ongoing Management is Critical 161 Site Selection Criteria 161 Other Potential Outplanting Situations 165 XII Conclusion 167 Acknowledgements 170 XIII Literature Cited 171 Photographs Page 1 Ventura marsh milkvetch in full flower at MSB-4 in the summer of 2004 2 2 Ventura marsh milkvetch fruits in various stages of maturity 9 3 Exposed root crown on planted individual in early winter, prior to reshooting 10 4a Infructescences retained on previous year’s stem, April 4, 2004, MSB-4 11 4b Ground littered with pods and infructescences 12 5 a) Bumble bee visiting Ventura Marsh milkvetch inflorescence b)Leptotes marina 13,14 6 MSB-4 original plot area in summer of 2005 following flooding 15 7a Ventura marsh milkvetch fruits in various stages of maturity 16 7b Grey and orange woolly bear caterpillar on milkvetch plant 16 8 MAND-1 plot in June 2003. 39 9 Scientific aid Anne McLeod examines a single VMMV surviving at CSMR-2, in 18 summer 2003 10 Naturally recruited juvenile in May 2003 19 11 Inverted planting tube showing young roots which have formed on nursery-raised 29 juvenile 12 Severe herbivory of new annual growth shoots forming on the near-surface root 30 crown of a naturally-recruited milkvetch 13a Wild site at North Shore, a group of juveniles in Colony “A” in June 2003 36 13b Several adult plants in full flower in “Colony B” area, in 2003 36 14a South Ormond planting site, wetland transition zone 38 14b South Ormond planting site, upper salt marsh zone 38 15 Dense masses of naturally recruited juveniles in early summer at MSB-5, following 42 flooding of the plot earlier that winter in 2005 16 Center of the CSMR-5 plot in May 2003, looking south 43 17 Center of CSMR-Plot 5, in summer of 2004, looking north 44 18 COPR Lagoon, August 9, 2004. Looking south 46 vi 19 COPR-Pond in August 2004 47 20 COPR-Pond in August 2005 49 21 COPR-Pond. August, 2005 49 22 August 2006 natural recruits at COPR-Pond 50 23 MSB-3 in January, 2005 53 24 MSB-3E (north plot extension) in August 2006 54 25 MSB-4, August 2004, looking northeast 55 26 Sudden loss of soil moisture or water table at COPR-Pond, August 2004 114 27 Moisture stress showing stages of color loss as vigor declines 118 28 Miniaturization on right, normal growth on left, CMSR-5, 2003 116 29 Miniaturization on reshooting CSMR-5 plant, 2004 117 30 Severely herbivorized area at CSMR 5C 83 31 Sudden decline of mature individual in full flower, CSMR-5, 2003 115 32 Young juvenile milkvetch in twiggy litter 92 33 Milkvetch and arroyo willow juveniles are protected amongst stems emerging from 93 below ground rhizomes of Mexican or Baltic rush 34 Juvenile at MSB-3 is being overtopped by goldenrod and western ragweed 93 35 COPR-Lagoon in May 2007 98 36 Masses of naturally recruited juveniles at CSMR-5C in mid-June, 2006 99 37 Abundant milkvetch juveniles amongst competitors in March 2005 on previously 102 inundated ground in the central MSB-3 plot 38 Milkvetch seed magnified 30 times, viewed through digital camera and eyepiece of 108 compound microscope Aerial Photographs Page 1 Mandalay State Beach and North Shore wild site, October 23, 1979. 34 2 South Ormond Beach planting site. Plot behind cypress trees. 37 3 Coal Oil Point Reserve-Pond introduction site 45 Maps Page 1 Vicinity 24 2 Ventura/Oxnard Area 25 3 Carpinteria Salt Marsh Reserve 26 vii 4 Coal Oil Point Reserve 27 Figures Page 1 Annual rainfall by water year at various sites 51,52 2 Depth to water table at various sites in centimeters 59 3 Survivorship of 2002 outplants at Carpinteria Salt Marsh Reserve 67 4 Survivorship of 2002 outplants at the McGrath State Beach sites 68 5 Mean height of longest shoot in original 2002 outplants 74 6 Mean number of flowering shoots in the original 2002 outplants 74 7 Mean number of inflorescences on randomly selected stem 74 8 Percent survival of 2004 outplants at more favorable planting sites 80 9 Number of milkvetch surviving at more favorable planting sites 81 10 2004 outplants- mean height of tallest shoot 87 11 2004 outplants- mean number of flowering shoots 87 12 2004 outplants- mean number of inflorescences on randomly selected stem 88 13 Mean number of shoots produced on first year plants, 10-11 months old, at key 89 sites; comparing sunny and shady locations with milkvetch planted in tree shelters 14 Number of naturally recruited juveniles documented at various sites during the 97 August monitoring sessions 15 Height of juveniles in early May 2003 at the McGrath State Beach and Carpinteria 100 Salt Marsh Reserve sites 16 Mean height of naturally recruited first year flowering and non-flowering cohorts at 106 key sites 17 Total vegetation cover at key sites 156 18 Total milkvetch cover at key sites 156 Tables Page 1 Overall status of Ventura marsh milkvetch at all sites in August 2006 7 2a Seed production at key sites in 2003 78 2b Seed production at key sites in 2004 78 3 2004 Outplants- Planting dates, number planted and percent survival through 23 summer 2006 4 Trees and Shrubs Closely Associated with Ventura Marsh Milkvetch Growing Sites 146 viii 5 Herbaceous Plants Closely Associated with Ventura Marsh Milkvetch Growing 147 Sites 6 Invasive Weeds Associated with Ventura Marsh Milkvetch Growing Sites 151 7 Plant Species Associated with Poorly Performing Dry Sites 159 8 2002 Outplants- Survivorship at experimental introduction sites through August 68 2006 9 2002 Outplants- Growth and flowering in their second growing season, August 72 2003 10 2002 Outplants- Growth and Flowering 2004-2006 73 11a Flower and fruit production at key sites in 2003 76 11b Flower and fruit production at key sites in 2004 76 12 Theoretical estimate of seed production in selected plants. 2002 estimate based 79 on data from Soza et al. 2003 13 2004 Outplants- Survivorship, growth and flowering in 2004 85 14 2004 Outplants- Survivorship, growth and flowering in 2005 and 2006 86 15 Monitoring status of wild population of Ventura marsh milkvetch in August 2006 91 16 Naturally Recruited Cohorts- Survivorship and flowering of 2003, 2004 cohorts 95 17 Naturally Recruited Cohorts- Survivorship and flowering in 2005 cohorts 96 18 Naturally Recruited Cohorts- Survivorship and flowering in 2005 cohorts 97 19 Status and flowering in naturally recruited cohorts- 2006 104 20 Distance of 2003 juveniles from the closest parent in centimeters 110 Appendix Appendix A.