Certain natural resources have been designated as "high resource value" areas due to their fragility and biological diversity. Together, these areas are the foundation of the Valley's ecosystem. Some cultural resources have also been designated "high resource value" due to their sensitivity and cultural significance. Specifically, the "high resource value" layer shown includes:

The Merced River. In Yosemite Valley, the most important natural process is the Merced River-- its flooding, its meandering. Most of the highest resource value areas are closely linked to the river. These areas often overlap and are critical in allowing natural processes to prevail.

Wetlands. Wetlands are an extension of the Merced River system and are generally located adjacent to the river and its tributaries. Wetlands have some of the greatest biological diversity and productivity of any natural community. Over the past 150 years Yosemite Valley's wetlands have become less productive due to the impacts of development and recreation.

Fragile Vegetation Communities
Riparian zones extend outward from the edge of Merced River and its tribuatires. Riparian communities are among the most productive in the Sierra Nevada. like wetlands, the riparian zones are also among the most impacted due to development and recreational activities along the river banks, and have also been declining in size since the late 1800s.
Meadows in Yosemite Valley link aquatic zones of the Merced River with permanently dry upland areas. Meadows depend on a relatively high water table to sustain native meadow vegetation. In the past 150 years, meadow communities have changed markedly in vegetative complexity, continuity of habitat, and in size-- decreasing from an estimated 745 acres to a current total of 65 acres. Meadows also are an important cultural landscape serving as the foreground "openings" from which people view the precipitous walls of the Valley.
California black oak woodlands have been reduced by about 90 percent in Yosemite Valley, based on comparison with early Valley photographs. Today, only four stands of black oak, totaling 143 acres, remain in the valley.

Areas with a high diversity of wildlife. Wildlife habitats of high value are defined by wildlife diversity which is found in high value vegetation comunities. Wetlands, riparian, and wet meadow habitats are of greater importance to wildlife than other vegetation communities.

Rich Soil Areas. Includes soils that either support or have the potential to be restored to high value vegetative communities. They include loams deposited by the Merced River and the terminal, recessional and medial moraines. Loamy soils generally support exceptional native vegetation communities-- particularly wetlands, meadows and riparian areas. The moraines, deposited during the most recent period of glaciation, were critical in the formation of the Yosemite Valley we see today.

National Historic Landmarks. National Historical Landmarks in Yosemite Valley include the Ahwahnee Hotel, the Ranger Club, and LeConte Memorial Lodge.

Archeological Sites. Archeological sites in Yosemite Valley are most important for their potential to answer key questions about how people lived in and managed their environments over the past several thousands of years. These places are most valuable where they have not been disturbed. Archeological sites with high research value are included, but only depicted on the map in such a way that does not put them at risk from vandalism or looting.