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City of Pleasanton—Hidden Canyon Residences and Preserve
<br />Draft EIR Biological Resources
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<br />FirstCarbon Solutions 3.3-5
<br />https://adecinnovations.sharepoint.com/sites/PublicationsSite/Shared Documents/Publications/Client (PN-JN)/2148/21480016/EIR/3 - Draft EIR/21480016 Sec03-03 Bio Resources.docx
<br />California Annual Grassland–89.35 acres
<br />The project site primarily supports California annual grassland habitat dominated by annual grasses
<br />and forbs of European origin. Vegetation identified within the annual grassland habitat of the project
<br />site during site surveys included, but was not limited to, yarrow (Achillea millefolium), common
<br />fiddleneck (Amsinkia intermedia), chamomile (Matricaria chamomilla), mugwort (Artemisia
<br />douglasiana), wild oats (Avena fatua), black mustard (Brassica nigra), ripgut brome (Bromus
<br />diandrus), red brome (Bromus madritensis ssp. rubens), Italian thistle (Carduus pycnocephalus),
<br />bindweed (Convolvulus arvensis), annual fireweed (Epilobium brachycarpum), California poppy
<br />(Eschscholzia californica), bedstraw (Galium spp.), Great Valley gum plant (Grindelia camporum),
<br />barley (Hordeum murinum), vetch (Vicia spp.), Congdon’s tarplant (Hemizonia parryi spp. congdonii),
<br />tree of heaven (Ailanthus altissima), coast live oak (Quercus agrifolia), blue oak (Quercus douglasii),
<br />and black locust (Robinia pseudoacacia).
<br />An unidentified tarweed (Holocarpha spp.) species was detected in a small area within the
<br />southeastern section of the project site. The Lester Property, Parcel C, has been grazed by cattle for
<br />several decades and supports vegetation consistent with grazed areas.
<br />Mixed Riparian Woodland–23.4 acres
<br />Devaney Creek, an intermittent stream fed by springs and runoff water, contains riparian habitat
<br />with a relatively dense, closed canopy. This creek system begins as two main channels with a few
<br />other drainages feeding the creek. During the May 2023 delineation survey, Devaney Creek conveyed
<br />water in sections within the property boundary. In previous surveys, Devaney Creek conveyed water
<br />intermittently, with some areas supporting flowing water while other areas were dry; feeder
<br />channels were also dry during the site visit. California bay (Umbellularia californica) is the dominate
<br />species of the riparian overstory. Other trees observed included California buckeye (Aesculus
<br />californica), madrone (Arbutus menziesii), fig (Ficus carica), walnut (Juglans sp.), sycamore (Platanus
<br />acemose), and elderberry (Sambucus nigra ssp. caerulea). Understory vegetation included, but was
<br />not limited to, coyote brush (Baccharis pilularis), Italian thistle, bull thistle (Cirsium vulgare), miner’s
<br />lettuce (Claytonia perfoliata), wild cucumber (Marah fabaceous), sticky monkey flower
<br />(Diplacusaurantiacus), California blackberry (Rubus ursinus), Hedge parsley (Torilis nodosa), poison-
<br />oak (Toxicodendron diversilobum). stinging nettle (Urtica dioica), and periwinkle (Vinca major).
<br />Channel beds were largely devoid of vegetation, with one of the culverted drainages supporting
<br />overstory similar to the riparian habitat and understory similar to the non-native annual grassland
<br />habitat. Additional vegetation includes poison hemlock (Conium maculatum), rabbit’s foot grass
<br />(Polypogon monspeliensis), and stinging nettle.
<br />Oak Woodland–10.4 acres
<br />Relatively small areas of oak woodland are associated with the project’s southeastern and
<br />southwestern edges and a small area along Dublin Canyon Road. Coast live oak dominates the
<br />overstory, which also includes the following species: tree of heaven, elderberry, and California bay.
<br />Species observed in the oak woodland understory included ripgut brome, gooseberry (Ribes sp.),
<br />California blackberry, bedstraw, hedge parsley, poison-oak, snowberry (Symphoricarpos albus var.
<br />laevigatus), and California wood ferns (Dryopteris arguta).
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