Assessments

* Natural Diversity Database

* Terrestrial Vertebrates Restricted to the Sierra Nevada

MANAGEMENT STRATEGY

* SNEP Significant Areas Inventory

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Prothro Creek watershed is one of several selected from the upper Cosumnes Basin as part of the solution to one BMA alternative (see volume II, chapter 58) (plate 5.5). As we noted earlier, this alternative starts with Class 1 lands as the BMA system and requires additional area for most middle- and high-elevation forest types as well as for foothill plant community types. The Prothro Creek watershed was selected to contribute area in Sierran mixed conifer forest, west-side ponderosa pine forest, Jeffrey pine forest, red fir forest, mixed montane chaparral, and montane manzanita chaparral. The watershed is located on the southern edge of El Dorado County, just northwest of Lower Bear River Reservoir. It is 9,257 acres in area and is 92% public land, 8% industrial timberland. Population density is very low, but 34% of the watershed was mapped in roaded area.
Management of the Prothro Creek watershed as a BMA would likely be oriented toward maintaining native biodiversity in montane forest, notably Sierran mixed conifer and red fir types. This could include (1) fire management to reduce the likelihood of severe, stand-replacing fires, (2) implementing silvicultural systems to attain desired forest compositional and structural properties on different sites, (3) removal or repair of some logging roads, (4) protection and restoration of aquatic systems and riparian buffers, (5) systematic monitoring and adaptive management of biota and ecosystem processes.
Roughly 10% of the watershed is mapped by the Eldorado National Forest as unsuitable for intensive timber harvest (plate 5.6), including a large Spotted Owl Habitat Area (SOHA) in the western half and riparian zones throughout the watershed. The late successional old-growth (LSOG) mapping team divided the Prothro Creek watershed into three polygons: two lower-elevation polygons mapped as montane mixed conifer and one higher-elevation polygon mapped as upper montane red fir. These labels are consistent with the GAP vegetation map, which divided the watershed into ten polygons. The LSOG mappers assigned the red fir polygon a rank of 3, and the two mixed conifer polygons ranks of 1 and 4 (see chapter 6). The two mixed conifer polygons were included in an Area of Late Successional Emphasis (ALSE) that extends to the south and west.
The Prothro Creek watershed highlights several features of the BMA strategy. First, the watershed encompasses a wide range of elevations and ecosystem types, and an effective management plan would have to account for these different types and their juxtaposition in the landscape. In this sense a BMA is quite different from many reservesfor example, U.S. Forest Service Research Natural Areasthat target one or a few ecosystem types. The presence of industrial timberland adds another layer of management complexity to this watershed.
Much of the lower watershed was recently harvested for timber, and, although the area is included in at least one proposed ALSE system, it was given an LSOG rank of 1. This illustrates the point that, because the GAP vegetation database does not include detailed structural information, the BMA solutions do not account for seral stage in representing forest types and thus could include recently burned or logged areas. Perhaps 60% of the Prothro watershed is in rank 3 red fir or rank 4 mixed conifer forestlands that are also classified as suitable for intensive timber management. Thus another concern in designating this watershed as a BMA is possible reduction of the commercial timber base in the Eldorado National Forest.

Management Implications

The case study of watersheds in El Dorado County (only two of which are summarized here; for more, see volume II) serves to emphasize the multisector, multijurisdictional nature of biodiversity conservation in the Sierra Nevada. Virtually every BMA that was examined included both private and public lands. One BMA spanned two counties, and another included both public and private industrial timberlands. It is difficult to envision how a regionally designed BMA strategy, implemented in the form of watershed-based ecosystem management aimed at native biodiversity, could be undertaken or succeed without transfer of management rights to a single administering agency, unless much more effective interaction and collaboration occur between the public and the private sectors and among local, state, and federal agencies.