Name: Areas with local barriers that are important for regional connectivity
Display Field: ID
Type: Feature Layer
Geometry Type: esriGeometryPolygon
Description: Critical Linkages were modified by local permeability to only show areas with limited local permeability that are important in a regional connectivity context (0.7 threshold). Local permeability shows the proportion of a 3km neighborhood that is accessible based on resistance from transportation and energy infrastructure, housing density and land cover
Copyright Text: TNC California, Bay Area Critical Linkages
Description: Permeability is a measure of the percentage of the area within a 3km radius of a point which can be moved through. The measure assumes that areas with more human influence and infrastructure are more difficult to move through than intact natural landscapes. Please see 2015 report "Conserving Nature's Stage: Identifying Resilient Terrestrial landscape in the Pacific Northwest" for more on methodology.
https://www.conservationgateway.org/ConservationByGeography/NorthAmerica/UnitedStates/oregon/science/Pages/Resilient-Landscapes.aspx
High values indicate high permeability, low values indicate low permeability
Description: This dataset represents a reconstruction of the historical landscape patterns (including channel and habitat distribution) of the Santa Clara Valley and adjacent baylands prior to extensive Euro-American modification. It integrates many sources of data describing the historical features of the study area. Extensive supporting information, including bibliographic references and research methods, can be found in these project reports:-Beller, EE, MN Salomon Grossinger, RM, 2010. Historical Vegetation and Drainage Patterns of Western Santa Clara Valley: A technical memorandum describing landscape ecology in Lower Peninsula, West Valley, and Guadalupe Watershed Management Areas. Prepared for the Santa Clara Valley Water District and The Silicon Valley Pollution Prevention Center. A Report of SFEI’s Historical Ecology Program, SFEI Publication #622, San Francisco Estuary Institute, Oakland, CA. http://www.sfei.org/scvheproject-Grossinger, RM, EE Beller, MN Salomon, AA Whipple, RA Askevold, CJ Striplen, E Brewster, and RA Leidy, 2008. South Santa Clara Valley Historical Ecology Study, including Soap Lake, the Upper Pajaro River, and Llagas, Uvas-Carnadero, and Pacheco Creeks. Prepared for the Santa Clara Valley Water District and The Nature Conservancy. A Report of SFEI’s Historical Ecology Program, SFEI Publication #558, San Francisco Estuary Institute, Oakland, CA. http://www.sfei.org/SouthStaClaraValleyHEStudy-Grossinger, RM, RA Askevold, CJ Striplen, E Brewster, S Pearce, KN Larned, LJ McKee, and JN Collins, 2006. Coyote Creek Watershed Historical Ecology Study: Historical Condition, Landscape Change, and Restoration Potential in the Eastern Santa Clara Valley, California. Prepared for the Santa Clara Valley Water District. A Report of SFEI’s Historical Ecology, Watersheds, and Wetlands Science Pro¬grams, SFEI Publication #426, San Francisco Estuary Institute, Oakland, CA. http://www.sfei.org/coyotecreek . See also http://www.sfei.org/UpperPen_HE-Grossinger, RM, RA Askevold, and JN Collins, 2005. T-sheet User Guide. A Report of SFEI’s Historical Ecology, Watersheds, and Wetlands Science Programs, SFEI Publication #427, San Francisco Estuary Institute, Oakland, CA. http://www.sfei.org/TSheetUserGuide***Paired with the reports, this dataset provides detailed information about early geomorphic and ecological characteristics of this region. A geographic information system (GIS) was used to collect, catalog, and analyze the spatial components of the study area. Historical maps and aerial photography were georeferenced, allowing us to compare historical layers to each other and to contemporary aerial photography and maps. Additionally, the georeferenced maps were used as means to geographically locate information gathered from surveyor notes, early explorers' journals, travelers' accounts, and newspaper articles. The GIS was used to capture a synthesis of the historical landscape. By integrating hundreds of georeferenced maps and photographs combined with narrative sources, we constructed a synthesis layer representing the historical landscape. Polygon and line layers were developed to depict features in the historical landscape. These layers include Historical Habitats, Historical Channels, and Historical Distributaries. Our classification system is described in further detail below. Historical Habitats mapped as polygons include: Alkali Meadow (high concentration)Alkali Meadow (low concentration)Box Elder GroveChaparralCoyote Riparian: Bar with Riparian WoodlandCoyote Riparian: Island with Riparian WoodlandCoyote Riparian: Low Flow ChannelDeep BayFloodplain SloughOak Savanna / Grassland Oak WoodlandPerennial Freshwater PondSalt Flat / SalinaSeasonal Lake / PondShallow BayShallow Tidal ChannelSycamore GroveTidal Flat / ChannelSeasonally Tidal MarshTidal Flat / ChannelTidal MarshTidal Marsh Panne Valley Freshwater Marsh Wet MeadowWild Rose Thicket Willow GroveHistorical Channels and Distributaries were mapped as polyline features. River and creek names were included in the attribute table. Channels were coded as follows: CreekMinor Tidal Channel / FlatSide ChannelSloughSwaleHistorical Distributary points were mapped to mark the endpoints of historically discontinuous channels.***Because this GIS dataset integrates four separate GIS datasets, there are some idiosyncracies in the way certain types of features were mapped:Channels are typically mapped as lines, but are mapped as polygons in a few cases: Coyote Creek mainstem (also mapped as lines in Historical Channel dataset)wide floodplain sloughs adjacent to San Felipe Lake in south Santa Clara Valley (also mapped as lines in Historical Channel dataset)wide tidal channels depicted on the T-sheets (NOT mapped as lines in Historical Channel dataset)Riparian habitats were mapped as polygons along the Coyote Creek mainstem. While many other streams had adjacent riparian habitats, only Coyote Creek's is mapped explicitly. Two small thickets of Wild Roses were ampped in West Santa Clara Valley onlyIn the Historical Channels dataset, swales were only mapped in south Santa Clara Valley.Modifications to earlier datasets have been integrated into this synthesis. Major examples of these modifications include: the remapping and reclassification of the few anthropogenic features depicted on the earlyT-sheetsremapping of Penitencia Creek and nearby wetlandsremapping of sloughs near the mouth of Calabazasreclassification of Grassland, Oak Savanna, and Oak Woodland habitatsclassification (splitting) of Alkali Meadows into high/low alkali concentrationsremapping of Historical Distributaries in the Coyote Creek study to conform with current historical ecology GIS methods***This geodatabase provides direct information about historical data sources, certainty levels, and notes pertaining to different areas and features. These allow the user to intelligently assess the applicability of the data for the chosen technical question. Refer to Grossinger et al. 2007 for detailed descriptions of these attributes.Primary and Secondary Source (Primary_Source, Secondary_Source):The major source materials used to map the feature are listed using, to the extent possible, standard textual citation form. Full bibliographic information can be obtained from the corresponding record in the Endnote bibliographic database and/or report bibliography. When a source directly contributed to the location of a feature, it was listed as a Primary Source; when it indirectly helped locate a feature, it was listed as a Secondary Source. Not all features have secondary sources.Certainty Attributes(InterpCert, Shape_Cert, Loc_Cert): Three distinct kinds of certainty are recorded: the certainty of our interpretation of the feature, its size/shape, and its location. Certainty of InterpretationThe following certainty level codes are used in the feature class attribute (InterpCert):High (H): Feature definitely representative of conditions circa 1769-1850.Medium (M): Feature probably representative of conditions circa 1769-1850.Low (L): Feature possibly representative of conditions circa 1769-1850.Certainty of Size and ShapeThe following certainty level codes are used in the feature class attribute (Shape_Cert):High (H): Accurate source material that probably closely follows actual shape; estimated to be within ±10% of actual area.Medium (M): Less accurate source material that probably generally follows actual shape; estimated to be between 50%-200% of actual area.Low (L): Inaccurate source material that may not follow actual shape; estimated to be between 25%-400% of actual area.Certainty of LocationThe following certainty level codes are used in the feature class attribute (Loc_Cert):High (H): Expected maximum horizontal displacement less than 50 meters.Medium (M): Expected maximum horizontal displacement less than 150 meters.Low (L): Expected maximum horizontal displacement less than 500 meters.NotesDirect and indirect quotes from data sources are included in this field when they were available. Other clarifying notes relating to evidence and methodology are included in this field as well***As with any map or GIS layer, confidence or certainty varies geographically due to differences in source data or methods. For more detail about methods refer to: Grossinger, RM, Striplen CJ, Askevold R, Brewster E, Beller EE. 2007. Historical landscape ecology of an urbanized California valley: wetlands and woodlands in the Santa Clara Valley. Landscape Ecology.:103-120.Technical users are strongly encouraged to read Grossinger et al. 2007 and the SFEI reports listed above (Beller et al. 2010, Grossinger et al. 2008, 2006, 2005) to gain a stronger understanding of the strengths and limitations of the dataset.
Copyright Text: San Francisco Estuary Institute 2011
Description: Richness of species within the Pajaro River Watershed, weighted by the suitability of the habitat. High values indicate species richeness higher than would be predicted by the habitat type, low values indicated lower species richness than would be predicted by the habitat type.
Description: Richness of threatened and endangered species within the Pajaro River Watershed, weighted by the suitability of the habitat. High values indicate species richeness higher than would be predicted by the habitat type, low values indicated lower species richness than would be predicted by the habitat type.
Description: Richness of mammal species within the Pajaro River Watershed, weighted by the suitability of the habitat. High values indicate species richeness higher than would be predicted by the habitat type, low values indicated lower species richness than would be predicted by the habitat type.
Description: Richness of bird species within the Pajaro River Watershed, weighted by the suitability of the habitat. High values indicate species richeness higher than would be predicted by the habitat type, low values indicated lower species richness than would be predicted by the habitat type.
Description: Richness of amphibian species within the Pajaro River Watershed, weighted by the suitability of the habitat. High values indicate species richeness higher than would be predicted by the habitat type, low values indicated lower species richness than would be predicted by the habitat type.
Description: Richness of reptile species within the Pajaro River Watershed, weighted by the suitability of the habitat. High values indicate species richeness higher than would be predicted by the habitat type, low values indicated lower species richness than would be predicted by the habitat type.