By Peter A. Stine

The coastal sage scrub (CSS) ecological community is distributed within a narrow band along the Pacific coast of North America, from central Baja California north just into southern Oregon. Within this geographic range, it is composed of several different floristic associations, dominated by California sage (Artemesia californica) and other drought-deciduous shrub species. The major concentration of CSS is from south of Point Conception, California, to central Baja California. Coastal sage scrub contains a species-rich and relatively unique biota. It occurs in a biogeographic zone of transition, including elements of more temperate climates as well as elements of more subtropical conditions. The California floristic province, of which CSS is a part, is considered one of the ecological "hot spots" of the world. This also happens to be a region where almost 20 million people now live and where population increases in the near future are expected to be significant. Several species of plants and animals found in this region have been listed as threatened or endangered in the last few years and many more are continuing to decline.

The NCCP Program The simultaneous trend of a growing human population and declining natural habitats led to passage of the Natural Communities Conservation Planning (NCCP) Act in 1991 by the State of California. Responsibility for implementing this State law rests with the California Resources Agency, and the U.S. Fish and Wildlife Service is providing assistance. The NCCP program establishes an approach to conserve State and federally-listed species by attempting to address entire ecological communities through the development of regional conservation strategies in cooperation with local governments, landowners, and other interested parties. The Geographic Information Systems (GIS--Note sidebar) approach has played a vital role in the planning for NCCP efforts, as it has in many other conservation programs around the world. It has been employed to assess the long-term conservation potential of CSS habitat throughout the 6,000-square-mile (15,240-square-kilometer) NCCP planning area. The results of this GIS analysis and its implications to conservation planning are discussed below.

The major goal of the NCCP program is to identify and implement a wildland reserve design that addresses multiple species and habitats throughout the planning area. Participating entities face the formidable challenge of delineating a preserve system, through a series of separate but coordinated local efforts, that will provide for the conservation of plant and animal species that depend on CSS. Local governments, assisted by Federal funding, developed a comprehensive GIS database to enable regional conservation planning efforts. Six regional efforts were initiated in the three primary counties involved in NCCP efforts (Orange, San Diego, and Riverside), and GIS data and analyses formed the foundation of the planning approaches. Highly detailed GIS data on vegetation, land ownership, rare soil types, roads, elevation models, and other subjects proved indispensable to the local planning groups.

During the initial stages of the NCCP program, a panel of scientists was convened to provide insight on ecological issues involved in the development of conservation and land use plans prepared under the NCCP. The major contribution of this Scientific Review Panel to the NCCP program was a set of Conservation Guidelines that, if followed, would lead to sound local and regional conservation strategies. Although the Conservation Guidelines were not intended to dictate detailed criteria for reserve design, they did provide a basis from which alternative designs could be evaluated.

The two wildlife management agencies responsible for reviewing and approving the regional plans, the Fish and Wildlife Service and California Department of Fish and Game, shared the GIS data with local governments. The spatially explicit evaluation criteria of the Conservation Guidelines were translated into a series of GIS operations that enabled biologists, planners, and decision makers to view a map-based representation of the conservation criteria against which alternative regional plans could be compared.

Geographic Information Systems Model This GIS model applied a series of four steps to the detailed vegetation GIS data. Under the Conservation Guidelines, vegetation and species location data were used to segregate existing CSS into areas of high, intermediate, and low long-term conservation potential. The four steps included:

• Determine higher-potential CSS habitat--This step involved combining and manipulating one or more layers of geographic information to produce a layer of data that identified larger, more intact stands of CSS. As a result, biological "core" areas of intact habitat and remote stands of disjunct habitat were identified and mapped.
• Determine CSS and other native habitats in close proximity to core CSS-- The next step identified other coastal sage (and other natural habitat types) within one-quarter to one-half mile of the core coastal sage area. These are the stands of CSS deemed by the Conservation Guidelines to have potentially significant, or "intermediate", conservation value.
• Identify CSS and other native habitats that may support populations of target species--Existing known locations of target species (i.e., species of special interest to the NCCP effort) were given additional weight in assessing the relative value of habitat. Many of these locations are included in GIS databases maintained by the California Natural Diversity Data Base and by local governments.
• Identify linkages between blocks of habitat defined as high/intermediate conservation potential--The final step involved a complicated set of GIS operations that identified a possible "least cost" path to link each core area with at least one other core area. This exercise demonstrated one method, based on some simple but sound ecological assumptions of how easy or difficult a given habitat type might be to traverse for a migrating or dispersing individual, for locating linkage between the isolated core areas. The results of this step showed the marginal value of establishing linkages between some of the more isolated core areas.

GIS alone cannot provide the answers to these complicated questions of preserve design. However, it is now an indispensable tool in the formulation of alternatives and the evaluation of proposals. Every component in the process, from the initial scoping and planning phases to the land management phases after a reserve system is put in place, will benefit greatly from this technology.

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Geographic Information Systems (GIS) is a rapidly advancing technology that enables people to develop, analyze, and display spatially explicit information. After incorporating thecoordinates of landscape features into a computer, users can manipulate map information from any source and visualize the landscape at any scale and with any combination of features. By creating computerized maps of project areas, the GIS database can identify species locations that are within, or near, the area of a proposed project. More advanced uses of GIS employ different kinds of spatial modeling to create alternative future scenarios of the landscape, allowing resource managers to compare the projected impacts of various land management strategies. GIS has significant potential value to natural resource managers in such fields as biological inventory and monitoring, land use planning, and ecological research. ^ TOP

-Curt Smith
USFWS Asst. Regional Director
North Pacific Coast Ecoregion ^ TOP

Graphic Information Systems map identifying major remaining concentrations of coastal sage scrub habitat in southern California.