Classification of Vegetation Associations from the Mount Tamalpais Watershed, Nicasio Reservoir, and Soulajule Reservoir in Marin County, California Julie Evens, Vegetation Ecologist In cooperation with With the assistance of Ed Kentner, Vegetation Staff Janet Klein, Vegetation Ecologist California Native Plant Society Marin Municipal Water District 2707 K Street, Suite 1 220 Nellen Avenue Sacramento, CA 95816 Corte Madera, CA 94925 Final Report 2006 TABLE OF CONTENTS Introduction...................................................................................................................................... 1 Background and Standards ............................................................................................................. 1 Methods ........................................................................................................................................... 2 Study Area................................................................................................................................... 2 Field Sampling............................................................................................................................. 3 Figure 1. Study area map of the Marin Municipal Water District lands (in dark green) for the 2005-2006 vegetation project. ................................................................................................ 4 Figure 2. Sample locations in the Marin Municipal Water District from 2005 in the study area with general geologic types.Vegetation Classification and Key.............................................. 5 Vegetation Classification and Key...............................................................................................6 Description Writing ...................................................................................................................... 8 Results........................................................................................................................................... 11 Basic Species and Vegetation Data.......................................................................................... 11 Classification Analyses ............................................................................................................. 11 Invasive Broom Species............................................................................................................ 11 Figure 3. Example of the cluster analysis output for the Relevé dataset with 7 group levels showing (from right to left) the arrangement and relationship of plots in the cluster dendrogram and the derived alliance classification.............................................................. 12 Figure 4. Example of the cluster analysis output for the Relevé dataset with 10 group levels showing (from right to left) the arrangement and relationship of plots in the cluster dendrogram and the derived association classification ........................................................ 13 Table 1. Significant indicator species (with p-values <0.05) from the Indicator Species Analyses for the Relevé dendrograms at the cluster group levels of 7 and 10 .................... 14 Table 2. Final vegetation classification from the Marin Municipal Water District, California, with alliances and associations nested within a higher-level hierarchy of divisions per the International Vegetation Classification System (IVCS)......................................................... 15 Table 3. Plant communities containing invasive broom species (Cytisus scoparius or Genista monspessulana), with average cover and frequency of the broom species provided. .............................................................................................................................................. 20 Key to Vegetation .......................................................................................................................... 21 Table 4. Field key to the main groups and vegetation associations of Mount Tamalpais, Nicasio Reservoir, and Soulajule Reservoir........................................................................................... 22 Tree Overstory Vegetation ............................................................................................................ 37 Aesculus californica Alliance or Habitat .................................................................................... 37 Aesculus californica-Umbellularia californica/Mimulus aurantiacus Association.................. 37 Alnus rubra Alliance or Habitat.................................................................................................. 39 Arbutus menziesii Alliance or Habitat........................................................................................ 41 Arbutus menziesii-Quercus agrifolia Association ................................................................. 41 Arbutus menziesii-Umbellularia californica (-Lithocarpus densiflorus) Association.............. 44 Arbutus menziesii-Umbellularia californica-Quercus kelloggii Association .......................... 46 Chrysolepis chrysophylla Alliance or Habitat ............................................................................ 48 Chrysolepis chrysophylla-Arctostaphylos glandulosa Association ....................................... 48 i Chrysolepis chrysophylla/Vaccinium ovatum Association .................................................... 51 Cupressus macrocarpa Alliance or Habitat............................................................................... 53 Cupressus sargentii Alliance or Habitat .................................................................................... 55 Cupressus sargentii (Pure) Association................................................................................ 55 Cupressus sargentii (Riparian) Association.......................................................................... 58 Cupressus sargentii/Arctostaphylos hookeri subsp. montana Association .......................... 60 Lithocarpus densiflorus Alliance or Habitat............................................................................... 62 Lithocarpus densiflorus-Arbutus menziesii Association........................................................ 62 Lithocarpus densiflorus-Umbellularia californica Association............................................... 64 Pinus muricata Alliance or Habitat ............................................................................................ 66 Pinus muricata/Arctostaphylos glandulosa Association ....................................................... 66 Pinus muricata/Vaccinium ovatum Association .................................................................... 68 Pseudotsuga menziesii Alliance or Habitat............................................................................... 70 Pseudotsuga menziesii (Pure) Association .......................................................................... 70 Pseudotsuga menziesii-Chrysolepis chrysophylla-Lithocarpus densiflorus Association...... 73 Pseudotsuga menziesii-Quercus agrifolia Association......................................................... 75 Pseudotsuga menziesii-Quercus chrysolepis Association ................................................... 77 Pseudotsuga menziesii-Umbellularia californica/Polystichum munitum Association ........... 80 Pseudotsuga menziesii-Umbellularia californica/Toxicodendron diversilobum Association 83 Pseudotsuga menziesii-Lithocarpus densiflorus Alliance or Habitat ........................................ 85 Quercus agrifolia Alliance or Habitat......................................................................................... 88 Quercus agrifolia/Grass (Annual) Association...................................................................... 88 Quercus agrifolia/Grass (Perennial Native) Association....................................................... 90 Quercus agrifolia/Toxicodendron diversilobum/Grass Association ...................................... 93 Quercus agrifolia-Arbutus menziesii-Umbellularia californica Association........................... 96 Quercus chrysolepis Alliance or Habitat ................................................................................... 98 Quercus chrysolepis-Arbutus menziesii-Lithocarpus densiflora Association ....................... 98 Quercus garryana Alliance or Habitat ..................................................................................... 100 Quercus kelloggii Alliance or Habitat ...................................................................................... 102 Quercus kelloggii-Arbutus menziesii-Quercus agrifolia Association .................................. 102 Quercus lobata Alliance or Habitat.......................................................................................... 104 Quercus lobata/Grass Association ..................................................................................... 104 Quercus wislizeni Alliance or Habitat...................................................................................... 106 Quercus wislizeni/Arctostaphylos glandulosa (Woodland) Association ............................. 106 Quercus wislizeni/Heteromeles arbutifolia Association ...................................................... 109 Quercus wislizeni-Quercus chrysolepis Alliance or Habitat.................................................... 111 Salix laevigata Alliance or Habitat..........................................................................................