Definition of Maritime Chaparral What is Maritime Chaparral? (Focus: Northern and Central Maritime Chaparral) in the Manual of California Vegetation
John O. Sawyer, Humboldt State University Professor Emeritus
Julie M. Evens, California Native Plant Society Vegetation Ecologist
Shrublands whose plants have sclerophyllous leaves and grow in Many habitats contain distinctive nutrient-poor soils on windward uplands plant species and characteristic and coastal lowlands of northern and vegetation types that make habitats central California (from Mendocino to easy to distinguish from Santa Barbara Cos.). other habitats.
“The kind of site or region with Northern/Central Maritime Chaparral respect to physical features (as soil, weather, elevation) naturally or exists on California’s coast normally preferred by a biological between southern Mendocino and species” – Merriam-Webster Dictionary Santa Barbara Cos.
Alkali sinks, fens, freshwater marshes, salt marshes, vernal pools
1 Maritime chaparral Maritime chaparral contains plants adapted to areas has nutrient-poor soils and occurs with cool, foggy summers, unlike on windward uplands and coastal interior chaparral types (where lowlands summers are not moderated by fog)
In maritime chaparral – Maritime chaparral Periodic burning is necessary for includes Arctostaphylos or renewal of plant populations that Ceanothus species, including any characterize the habitat. narrow endemics considered rare and endangered. Recent fire suppression practices have reduced the size and They characterize the habitat. frequency of wildfires in the habitat.
In maritime chaparral – In maritime chaparral – Recent conditions favor longer- lived Agricultural conversion, residential shrubs and trees over shorter-lived, development, and fire suppression crown-sprouting or obligate-seeding have fragmented and degraded shrubs characteristic of the habitat. the habitat.
Obligate-seeders tend to occur in Preservation and management are less fire-prone areas that generally high priorities. burn more intensely when fires occur.
2 A vegetation type is a collection of stands that have similar structure and floristic composition.
Habitats are made up of one or more vegetation types.
The same vegetation type can occur in more that one habitat.
Coast live oak forests differ in structure and in floristic composition from the Maritime chaparral is shrublands of the maritime chaparral. characterized at different levels Coast live forests and woodlands are associated with maritime chaparral, but At the vegetation level are not strictly part of the habitat. At the stand level Adjacent oak stands may reflect rare associations with maritime chaparral At the individual plant level indicator species.
Arctostaphylos montana ssp. The vegetation of maritime chaparral involves montana association several alliances, associations, and individuals.
Arctostaphylos montana shrubland alliance Arctostaphylos montana ssp. montana association [1, 2] Arctostaphylos montana - Adenostoma fasciculatum association [1] Associations restricted to Mount Tamalpais on rocky, serpentinite soils below 600 m
Arctostaphylos montana ssp. ravenii A single individual (clone) in San Francisco at the Presidio above Arctostaphylos montana - Bakers Beach (other 5 occurrences were extirpated) Adenostoma fasciculatum association [1] Evens et al. 2006b, [2] Keeler-Wolf et al. 2003a
3 Some alliances are more widely distributed, The vegetation of maritime chaparral occurring on unproductive sandstone and involves special stands and individual granitic outcrops with sandy soils. species (examples below). Arctostaphylos crustacea shrubland Less than 10 Arctostaphylos bakeri stands Occurs from Marin and Napa Cos., south to Restricted to Sonoma Co. on rocky, serpentinite soils below Santa Barbara Co. 800 m
Arctostaphylos hookeri shrubland The 5 Arctostaphylos imbricata stands Occurs in Santa Cruz Mountains, Prunedale Hills, Restricted to San Bruno Mountain (San Mateo Co.) on Fort Ord, Monterey Peninsula exposed, rocky areas with a lack of soil development below 400 m
Proposed Maritime Chaparral Types The vegetation of maritime chaparral may involve rare species found as individual at the Alliance/Stand Level Arctostaphylos crustacea shrubland* plants. Arctostaphylos hookeri shrubland Arctostaphylos hooveri shrubland* Arctostaphylos hookeri ssp. hearstiorium Arctostaphylos montana shrubland* plants mix in shrubland and grassland types in Arctostaphylos morroensis shrubland* San Luis Obispo Co. Arctostaphylos nummularia shrubland* Arctostaphylos pajaroensis shrubland Arctostaphylos pacifica Arctostaphylos pumila shrubland few plants on San Bruno Mountain in Arctostaphylos (rudis, purissima) shrubland Arctostaphylos silvicola shrubland San Mateo Co. Arctostaphylos tomentosa shrubland Arctostaphylos andersonii Alliances Partially within or Related to Maritime Chaparral individual plants that mix with tree Arctostaphylos canescens shrubland* Adenostoma fasciculatum shrubland and chaparral stands in Santa Arctostaphylos manzanita shrubland Closed cone conifer woodlands Arctostaphylos glandulosa shrubland* Quercus agrifolia woodlands Cruz Co. Arctostaphylos myrtifolia shrubland* *formally defined with recent survey data and analysis
We need to describe and to classify vegetation that makes up maritime chaparral and work to understand its dynamics, so that we can better manage and preserve this important aspect of California’s biodiversity.
4 Releve sampling with Example Data Collection and Description Arctostaphylos silvicola from the Santa Cruz Sandhills dominant in stands
Arctostaphylos silvicola chaparral stands, conifer stands, and open sandy vegetation A version of northern maritime chaparral on nutrient-poor sandstone and marine sediments Associated rare plants and animals: Ben Lomond spineflower, Ben Lomond buckwheat, Santa Cruz kangaroo rat, Mount Hermon June Beetle Only small isolated patches exist (threatened by development and quarrying) Associated species include rare endemics such as Chorizanthe pungens var. hartwegiana
Photo per J. McGraw
Example Data Collection & Analysis Results of Constancy/Average Midpoint Cover for from the Gabilan Range Species with Significant Indicator Values 23 releves collected at Reeves Ranch per Group 1 Arctostaphylos crustacea - Adenostoma fasciculatum Susan Bainbrige & The Nature Conservancy - Ceanothus (cuneatus, papillosus) Group 2 Arctostaphylos crustacea Distance (Objective Function) Group 5 Arctostaphylos crustacea - Arctostaphylos gabilensis 2.5E+00 1.2E+02 2.3E+02 3.5E+02 4.6E+02 Information Remaining (%) 100 75 50 25 0 Group Adfa Adfa SaSo CePaP CeCuC RhCaC ArCr ArCr ArGa ArGa QuWiF QuWiF - -l -m -l -m -m -m -l -m -l -m -l -t RR1 RR9 group3 RR15 1 67 / 1 100 / 37.5 100 / 5 67 / 1 100 / 13.5 33 / 0.8 33 / 0.2 100 / 13.5 33 / 0.2 0 / 0 0 / 0 0 / 0 RR5 1 2 5 RR11 RR23 2 44 / 0.4 100 / 10 89 / 0.9 33 / 0.4 33 / 0.2 0 / 0 89 / 3.4 100 / 43.6 0 / 0 33 / 0.8 33 / 4.3 22 / 4.4 RR6 RR12 RR16 RR19 5 100 / 9.7 100 / 23.7 82 / 3.9 36 / 0.4 36 / 0.4 0 / 0 91 / 2.4 91 / 9.8 55 / 1.1 100 / 14.1 0 / 0 0 / 0 RR13 RR18 RR14 RR25 Species highlighted in bright blue had Indicator Values >30 RR2 RR4 RR7 RR8 RR20 RR22 RR21 RR3 RR10
Ordination Diagrams Basis for Definition of Maritime
group3 group3 1 1 Chaparral Vegetation Types 2 2 Chaparral Vegetation Types 5 5 Presence of indicator species (including rare and
gravel endemic taxa) c0-25cm Localized manzanita or ceanothus species (may or bedrock, total-exotic Localized manzanita or ceanothus species (may or livestem c5-10m livestem total-tall fines c0-25cm c5-10m may not be dominant or co-dominant) total-tall fines bedrock, total-exotic Axis 3 Axis 2 Structurally similar stands that repeat in the landscape c50-100cm fire2 fire1 Environmental site conditions (harsh soils, fog- moderated summers, varied fire return intervals)
Data and analysis are needed to provide the definitions of the different types and levels of rarity Axis 1 Axis 1 R-squared R-squared Axis Increment Cumulative Axis Increment Cumulative 1 .378 .378 1 .378 .378 2 .126 .504 3 .197 .575
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