Basin Delineation
County Delineation
Population and Population Density
Land Ownership
Management Classes
Land Management Status
Biodiversity Management Areas
Status by Elevation Zones
Public-Private Interface
Roadedness
Late-Succesional/Old Growth Rank
Gap Analysis
Significant Natural Areas
Times Burned
Fuel Models
Aquatic Diversity Management Areas
Areas of Late Successional Emphasis
Land Suitability Class, Timber Regulation Class, Availability Class
 

Description

The watersheds used for summarizing SNEP findings were derived from the CALWATER map. CALWATER is a set of standardized watershed boundaries, nested into larger, previously standardized watersheds, meeting standardized delineation criteria. CALWATER was developed by the California Interagency Hydrologic Basin Mapping Committee (CDF,DWR,DFG,SWRCB,USBR,USFS,USGS) as a hierarchial delineation of Hydrologic Regions (Level 1), Hydologic Units (HU, Level 2), Hydrologic Areas (HA, Level 3), Hydrologic Sub-Areas (HSA, Level 4), CDF Super-Planning- SPW, Level 5), and CDF Planning-Watersheds (PW, Level 6) on 1:24,000-scale, 7.5'-series USGS quads. Levels 5 and 6, applied statewide except for the Central Valley floor and southern California coasts and deserts, are intended primarily for CDF timber, rangeland, and related watershed planning. USGS HUCs can be assembled by dissolving internal boundaries of CALWATER at a combination of Level 2 and Level 3 boundaries. The basins (watersheds) used for summarizing SNEP findings are the Level 2 HUs.

SNEP Report: Addendum, Chapter 2
SNEP GIS Theme: not available

Description

Most land use planning occurs at the level of counties.  A coverage of county boundaries was used to summarize the thematic and spatial data from SNEP.  The boundaries include only the portion of the county within the SNEP core area.

SNEP Report: none
SNEP GIS Theme: Counties

Description

Land cover for the Sierra Nevada was mapped by the California Gap Analysis Project team at the University of California, Santa Barbara. This medium-resolution map of actual land-cover of California was produced using summer 1990 Landsat Thematic Mapper satellite imagery, 1990 high altitude color infra-red photography, the Vegetation Type Maps based on field surveys conducted between 1928 and 1940, miscellaneous recent vegetation maps, and ground surveys. Initial landscape boundaries were drawn by manual photointerpretation of the satellite imagery. The minimum mapping unit for upland land-cover was 100 ha and 40 ha for wetlands. Median map unit size in the Sierra Nevada region was approximately 400 ha. The final land-cover map includes distribution information on natural plant community types used by the California Natural Diversity Data Base (the so-called "Holland" classification) and land use classes, which were also classified as wildlife habitat types. A formal accuracy assessment of this map has not been conducted, but initial comparisons indicate that the map is in close agreement with other, recent vegetation maps. The version of the Gap Analysis Project land-cover map used for this watershed summary is the 8/98 release, not the 6/96 SNEP version. The later version corrected some minor errors and slightly simplified the classification of types to be more consistent with other regions of the state.

SNEP Report: Volume II, Chapter 23
SNEP GIS Theme: SNEP version (1996)      Final CA-GAP version (1998)

Description

The ownership data were derived from the 1:100,000 scale Bureau of Land Management Surface Management Status maps. The most recent national forest maps and other sources were used by The California Department of Forestry and Fire Protection to update the BLM maps prior to digitizing. Additional updating was done at UCSB. Many larger areas could be found on the USGS 1:100,000 scale topographic maps revised in the 1980s. Fish and Game Ecological Reserves and Wildlife Areas and Nature Conservancy Preserves were provided as digital files from the California Department of Fish and Game's Heritage Program. This theme was used for the gap analysis of plant communities in SNEP. However, the version compiled for the California GAP is only available through the Teale Data Center to their subscribers. A 1:2,000,000 scale version is available through the CA-GAP web site (see below).

SNEP Report: Volume II, Chapter 23
SNEP GIS Theme: CA-GAP 1:2,000,000 scale version

Description

Land management classes were developed as part from the ownership layer for the California Gap Analysis Project. It was modified by the inclusion of information from the Land Suitability Class map and maps of grazing allotments for National Forest lands.  Thus it combined status based on designation for biodiversity management with permitted land uses within the status 3 public lands.  This classification of management status is different than that used for GAP, which had 4 management status levels.

SNEP Report: Volume II, Chapter 23
SNEP GIS Theme: Management Class Layer

Description

Land management was developed as part of the ownership layer (see above) for the California Gap Analysis Project. The most recent national forest maps and other sources were used by The California Department of Forestry and Fire Protection to update the BLM maps prior to digitizing. Additional updating was done at UCSB. Many larger areas could be found on the USGS 1:100,000 scale topographic maps revised in the 1980s. Fish and Game Ecological Reserves and Wildlife Areas and Nature Conservancy Preserves were provided as digital files from the California Department of Fish and Game's Heritage Program. In addition, designated areas on public lands were incorporated for sites such as wilderness areas, research natural areas, and so on. All lands were categorized into 4 levels of management status based on the stated management objectives for the area. This theme was used for the gap analysis of plant communities in SNEP. This classification of management status is different than that used for SNEP, which had 5 management classes. It is not used here because it did not cover all areas for which this watershed reporting site is designed. The 1:100,000 scale version compiled for the California GAP is only available through the Teale Data Center to their subscribers. A 1:2,000,000 scale version is available through the CA-GAP web site (see below).

SNEP Report: Volume II, Chapter 23
SNEP GIS Theme: CA-GAP 1:2,000,000 scale version

Description

This topic generates a list of areas currently managed for biodiversity conservation (status 1 and 2 from the status layer described above).

SNEP Report: Volume II, Chapter 23
SNEP GIS Theme: CA-GAP 1:2,000,000 scale version

Description

The proportions of biodiversity management areas (status 1 and 2) can be compared to the proportions of land area by elevation zones to identify bias or uneven distribution of protection.  This information is presented in two columns, one with the percentage of all biodiversity areas in each elevation zone, and one with the percentage of all land in the zones.  The elevation data was provided by the California Gap Analysis Project which compiled the data from USGS sources at 100 meter cell size.

SNEP Report: Volume II, Chapter 23
SNEP GIS Theme: not available

Description

This variable is an index of the complexity or density of boundaries between public and private lands within the analysis unit.  The index is in units of kilometer of boundary per square kilometer of land.  It is derived from the land ownership layer.  All public lands, including reserves owned by non-profit conservation groups, were aggregated.  All interior boundaries were then dissolved, and then remaining boundary length was summed.  The index was used in SNEP as part of a rating of the suitability of watersheds for selection as biodiversity management areas.  The assumption was that higher values of this index indicated complex ownership patterns, such as the checkerboard of private and public lands along railroad rights-of-way, would be more difficult to manage for biodiversity than places with low values.

SNEP Report: Volume II, Chapter 58
SNEP GIS Theme: CA-GAP 1:2,000,000 scale version

Description

Road data from the 1990 1:100,000 scale TIGER files (Bureau of the Census 1989) were buffered with a buffer width related to the class of road. This buffer operation was used to estimate the area of land actually impacted by the presence of each road, where freeways were assumed to affect a greater spatial extent than dirt roads. A "roadedness" index was calculated for each watershed by summing the area of buffered roads, dividing that sum by the total area in the watershed, and multiplying by 100. Within the entire state, 21% of the land area is within road buffers. The road data in the SNEP report was derived from the USGS Digital Line Graph version of roads, which was the basis of the TIGER files. In SNEP, roadedness was used as one measure of suitability of sites for biodiversity management.

SNEP Report: Volume II, Chapter 58
SNEP GIS Theme: not available

Description

Population data from the 1990 census data were obtained by UCSB from the Consortium for International Earth Science Information Network (CIESIN) [ftp://ftp.ciesin.org/pub/census/usa/grid/pall/us/]. CIESIN had interpolated block group data to a 1 km lattice of the United States. We converted this lattice into a grid and cropped it to the state of California. Total population was estimated by summing population from all the 1 km cells in a watershed. Density was computed by dividing estimated population by the land area in each watershed. In SNEP, population density was used as one measure of suitability of sites for biodiversity management.

SNEP Report: Volume II, Chapter 58
SNEP GIS Theme: not available

Description

This layer consists of a composite of significant fire boundaries from historic and most recently mapped data.  Most source data is at 1:24,000 scale. Information includes year of fire, fire index number, and cause as well as number of fire occurrences in a selected area.  For this analysis, we have summarized the proportions of the analysis unit by the number of times burned.  These layers are for National Forest land only. Although the layer may cover private land within a National Forest boundary the data are only accurate for the National Forest land.

SNEP Report: Volume II, Chapter 41
SNEP GIS Theme: Fire History

Description

Generalized surface fuel characteristics as expressed by the composition and structure of the dominant vegetation occurring in the SNEP core area. Sites dominated by grass, lodgepole pine/redfir, and plantation represent relatively low hazard areas. Dense true fir and intermediate brush types indicate areas of moderate hazard. Pine with grass and shrub understory, pine/mixed conifer, logging slash, and mature chaparral represent areas of high to extreme fire hazard.  Surface fuel characteristics are used for evaluating fire hazard.  The layer was summarized by the analysis unit into the percentages of fuel types.

SNEP Report: Volume III, Chapter 19
SNEP GIS Theme: Regional Fuel Map

Description

Late-succsional, including old growth,LS/OG, forest conditions were assessed for the Sierra Nevada by the SNEP team. Conditions were assessed using stand structure criteria as measures of the level of LS/OG forest function, such as providing habitat for LS/OG related species. Larger landscape units which were relatively uniform in type and distribution of vegetation patches were mapped using available imagery, maps, ground-based information and the expert interpretations of resource specialists. Characteristics of the major patch types in each polygon were identified and tabulated and a composite late-successional structural ranking was calculated for each polygon on a scale that extended from 0 (no contribution) to 5 (veryhigh level of contribution). Only lands managed by the Forest Service, National Park Service, Bureau of Land Management, and state parks were mapped.

SNEP Report: Volume II, Chapter 21
SNEP GIS Theme: These data are in 16 separate layers, one for each management jurisdiction (see the SNEP web site at the Information Center for the Environment for these coverages). To use these data you will also need the ARC/INFO info file named lsog_final. This file contains the attribute information for the LSOG polygon coverage. The link/relate item is poly_id. You will also need the data dictionary named lsog_dd.

Description

A number of options for watershed management are possible, ranging from biodiversity-oriented management of all watersheds to simply reacting to the need to keep species from becoming extinct. A middle series of options was investigated by the SNEP team. Forty-two watersheds were identified by the SNEP team as Aquatic Diversity Management Areas (ADMAs), whose first goal of management would be the protection of aquatic biodiversity. The watersheds were selected on the basis of size (greater than 50 km2), natural hydorlogic regime, presence of native fish and amphibians, and representativeness.

SNEP Report: Volume II, Chapter 57
SNEP GIS Theme: not available

Description

SNEP mapped 945 areas in the Sierra Nevada of ecological, cultural, and geological significance. Local agency specialists familiar with local areas mapped these areas during workshops held throughout the Sierra Nevada. This layer contains SNEP significant area polygons for National Parks and National Forests in the Sierra Nevada region. A small area of Bureau of Land Management land was also mapped. Areas mapped reflect three main types: (1) ecological (which combines genetic attributes, plant and animal species, and plant communities) and natural processes, (2) cultural, and (3) geological types. Within each category, areas were selected for rarity, richness, and representativeness. Each polygon is also described by narrative comments, management goals, and current impacts. The coverages can be linked to the database sigars_info by the join item poly_id.

SNEP Report: Volume II, Chapter 29
SNEP GIS Theme: sigars_info INFO table      Cultural Areas      Ecological Areas      Geologic Areas

Description

A Working Group on Late-Successional Conservation Strategies developed a framework for evaluating the effectiveness of alternative conservation strategies that had been or will be proposed for late-successional forests in the Sierra Nevada. One of the alternative strategies evaluated emphasized management of large landscape units based upon one or (usually) multiple LS/OG polygons. "ALSE" was selected as the label rather than "reserves" to acknowledge the need for an active management approach to maintenance of high-quality LS/OG forest ecosystems, which is a primary management objective. A major objective in designing larger areas of LS/OG emphasis was creation of efficient management units, such as for implementing activities to reduce the potential for loss to catastropic fire. As with the LS/OG maps, ALSEs were only delineated on state or federal lands.

SNEP Report: Addendum, Chapter 3
SNEP GIS Theme: INFO table for ALSEs. To use this table, you will also need to have the 16 layers from the national forests, national and state parks, and the Bureau of Land Management to relate the rating to LS/OG polygons.

Description

This information was compiled for each National Forest in the SNEP region to track the timberland allocations in the Forest plans.  This is a derived layer of forestland capability, suitability, and availability for timber production.  Capable forestland is determined from the CALVEG types. Suitability information is derived from capable CALVEG types that are available, minus the unsuitable forest lands. Availability is derived by determining all forestland from CALVEG type, minus the congressional withdrawn and pending withdrawal. For all lands that are tentatively suitable for timber production, a determination of final forestland allocations under the Forest Plan is made, using all constraint layers. The most constraining resource is coded for each acre on the National Forest.The most constraining resource is coded for each acre on the National Forest.  Land suitability was also used in determining management classes for gap analysis.  All three attributes (land suitability [PLSCLSC], timber regulation class [PLSCREG], and availability class [PLSCAC]) are included in the land suitability coverage.

SNEP Report: Not included.
SNEP GIS Theme: Land suitability coverages by National Forest.