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<br />vegetation in the Planning Area includes annual emergent species such as cattails, sedges, watercress,
<br />
<br />tules, and curly dock. Other species include rabbit's foot grass and water smartweed. Wetlands
<br />
<br />provide habitat for a number of wild creatures, including waterfowl and amphibians, such as
<br />
<br />salamanders. Figure VII -1, above, identifies lakes and lacustrine areas and also riparian corridors.
<br />
<br />Riparian Corridor. Some, but not all, wetlands are also riparian areas. Riparian vegetation grows
<br />along streams, arroyos, and drainage ditches. Riparian woodlands dominate some watercourses and
<br />include willows, white alders, big-leaf maples, and sycamores, all tolerant of saturated soils. Valley oak,
<br />California bay laurel, black walnut, black cottonwood, and California buckeye trees also grow in
<br />Pleasanton's riparian areas. Below the riparian tree canopy are shrubs such as poison oak, California
<br />blackberry, poison hemlock, wild oats, ryegrass, mulefat, sedges, ferns, bromes, burr clover, stinging
<br />nettles, white sweetclover, wild radish, vetch, and mint. Other native species include California
<br />button-bush, coyote brush, mugwort, elderberry, snowberry, and California rose. Riparian woodland
<br />is one of the most valuable native habitat types in California because it supports a diversity of wildlife
<br />species, many of which are rare or uncommon.
<br />
<br />Arroyo del Valle, Arroyo Mocho, Arroyo de la Laguna, and other riparian corridors in the Planning
<br />Area provide food, water, rnigration and dispersal corridors, breeding sites, and thermal cover for
<br />wildlife. A mixture of native and non-native plants grows in riparian, lacustrine (related to lakes), and
<br />other wetland areas.
<br />
<br />The City of Pleasanton designates trees over 55 inches in circumference or 35 feet in height as
<br />
<br />"Heritage Trees" subject to special regulations governing their removal. 8 Many trees of this size grow
<br />
<br />on Pleasanton Ridge and the Southeast Hills, in the Downtown area, along the western segment of
<br />
<br />Bernal Avenue, along Stanley Boulevard near Reflections Drive, and in the Mohr-Martin
<br />
<br />neighborhood. The most common of these trees include valley oak, Monterey pine, California black
<br />
<br />walnut, eucalyptus, sycamore, black locust, and California box elder. Of all of the tree species growing
<br />
<br />in Pleasanton only the Northern California black walnut is a federal Species of Concern.
<br />
<br />Soil Resources
<br />
<br />Soils are a natural resource contributing to the viability of agriculture and grazing activities,
<br />groundwater recharge, plant and animal habitat productivity, and development suitability. Healthy soil
<br />contributes to productive crops and rangelands, vigorous woodlands, diverse wildlife, and building
<br />integrity. Soil does this by performing five essential functions:9
<br />
<br />.
<br />
<br />Regulating water. Soil helps control the path of rain, snowmelt, and irrigation water including
<br />whether water flows over the land or into and through the soil.
<br />
<br />8 City of Pleasanton. Pkasanton Municipal Code, Section 17.16: Tree Preservation.
<br />
<br />9 United States Department of Agriculture, Natural Resources Conservation Service. htlV:/ /~oils.usda.!?ov/s$L. Apr. 11,
<br />
<br />2006.
<br />
<br />Con os FJt:ment, CC 082~J6, dean
<br />
<br />VII-8
<br />
<br />Ciry Council 8/29/2006
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