ASSESSMENTS

* Natural Diversity Database

* Terrestrial Vertebrates Restricted to the Sierra Nevada

Management Strategy

* SNEP Significant Areas Inventory

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Sierra Nevada Plant Communities

The Sierra Nevada Ecosystem Project assessed all vegetated areas of the Sierra Nevada (15.6 million acres); 89.7% of the region is covered by plants (plate 5.1). The rest is rocky barrens, water, or settled lands. Eighty-eight natural plant community types have been described within the Sierra; about one-quarter of them have ranges of less than 6,000 acres. Conversely, twelve community types collectively contribute two-thirds of the regions total vegetated acreage (table 5.1).

Ownership and Management of Sierran Plant Communities

The SNEP assessment of terrestrial biodiversity focused mainly on the structure of commercial forest types, such as Sierran mixed conifer and red fir, and on the condition of selected rangeland communities, such as meadow and riparian types. Our findings are presented in more detail in chapters 23 and 58 of volume II. We did not systematically investigate the condition and trends of many of the regions ecosystems, but we did map the general distribution of all widespread plant communities, which we used as coarse surrogates for terrestrial ecosystems and wildlife habitats. We analyzed the distribution of each widespread type with respect to land ownership and management. Our objective was to identify types that might be especially vulnerable to land-use conversion or degradation because they are not well represented in existing designated conservation areas or are largely on land available for uses that could negatively impact native biodiversity. This map-based conservation risk-assessment method is known as gap analysis because it seeks to identify gaps in the representation of native biota in protected areas. Gap analysis is not a substitute for a detailed biological inventory, but it provides a useful description of regional vegetation patterns and helps to identify vulnerable plant communities and habitats. Our study was a collaboration with the National Biological Services Gap Analysis Program (GAP).