1: Conservation of biological diversity

This indicator, “Integrity of Natural Fire Regimes,” spatially and temporally quantifies acres of rangeland burned annually. Fire is a key ecological driver in many rangeland ecosystems, facilitating nutrient cycling, promoting recruitment of native grasses and forbs, and limiting encroachment of woody species. For many rangeland ecosystems, the introduction of domestic grazers, invasive species, conversion of rangeland to cropland, urbanization, fire suppression, and fragmentation of rangeland have significantly altered the natural fire regimes as well as landscape composition and structure. Because fire is such a dramatic disturbance, changes in its frequency or intensity results in significant changes in nutrient cycling, species richness, ecological integrity, and carbon stocks. Monitoring the integrity of fire regimes promises to significantly inform evaluations of rangeland health.

This indicator provides a surrogate measure of intensive human uses of rangeland through the use of road density measures and housing densities. Many intensive uses of rangeland are often not represented in land cover maps because of their small individual spatial extents. Examples of these types of land uses of rangeland include low-density rural housing developments, power lines, off-road vehicle (ORV) uses, mines, and oil and gas wells, along with their associated transportation infrastructure. The potential ecological impacts of intensive human uses of rangeland include loss and fragmentation of rangeland, rangeland plant communities, and open space, reduced primary and secondary productivity and biodiversity, increased soil disturbance and susceptibility to wind and water erosion, disruption of material flows and ecological processes in the landscape (e.g., groundwater flow), fire spread, and enhanced opportunities for successful establishment of invasive plants and animals.

To monitor the biodiversity of an ecosystem, based on integrity of the selected keystone species within that ecosystem. Monitoring keystone species populations, such as beavers, mountain lion, maple or aspen, can be a proxy as an indication of the state of genetic diversity within an ecosystem. More often than not, monitoring all populations in an ecosystem is not feasible, so tracking a keystone species can act as a proxy for all other species in that ecosystem. The keystone species must be carefully selected.

To track stream biological integrity based on sediment and nutrient loads, and temperature. Stream conditions affect its biological integrity, and fish are particularly impacted due to their sensitivity to environmental disturbances (flow regime, chemical and organic changes, thermal fluctuations, etc.). CWA 303(d) impaired stream listings are available in GIS format, and can be used to measure the proportion of total stream length per watershed. Also, NatureServe provides an ecological integrity assessment for wetland mitigation in some counties.

To track water courses that are unimpaired by dams and barriers and available for fish passage. The status of stream impairment can change, for instance if a dam is removed. Other streams may have natural barriers, such as waterfalls, landslides or large boulders. The Passage Assessment Database inventories potential barriers to fish and can be used to track impaired and unimpaired streams throughout California’s forest and rangeland.

Evaluates level of new (and recent historical) development in counties and regions. Data on new housing starts shows the intensity of development, recent and historical, by location (county, region, etc.) across the state. These are where developers are expecting (or expecting to lure) new inhabitants to live, and also show potential impacts to the land use and the greater land base, particularly from the lower density types of housing.

This indicator measures the numbers and geographic ranges of rare or “at-risk” species that occupy rangeland habitats for a significant portion of their life cycle, as well as the presence and extent of rangeland plant communities of concern. Trends in the number of at-risk species and communities help identify potential loss of historical and natural rangeland ecological functioning, as well as the loss of associated values and benefits. There are several metrics that could be used to describe the indicator. For species, metrics include the number of species, the number of populations per species, the abundance (number of individuals) per population, and the geographic range. For communities, metrics include the presence and number of at-risk communities, the number of stands of each community, the size of the stands, and the geographic range of the community.

The indicator relates to abundance of wetlands in the rangeland landscape. Wetlands for this indicator include depression (e.g., vernal pools) and slope wetlands but do not include riverine or floodplain wetlands that are covered under the “Extent and Condition of Riparian Systems” indicator. This indicator measures the number and total area of wetlands within all or portions of the rangeland system. The metric may be either a) numbers of individually identifiable wetlands and acreage for a particular region, or for the entire rangeland region, or b) numbers and percent of landscape occupied by wetlands.

This indicator provides information on the number and status of forest-associated species at risk or in serious decline. As a result, these species may require specific action or intervention to ensure their survival. The number of species at risk and their status is a measure of the health of forest ecosystems and their ability to support species diversity.

This indicator provides information on the health of forest ecosystems through the number of native forest-associated species.Knowledge of the number of native forest-associated species highlights the importance of certain forest types in meeting conservation objectives and in understanding the relationships species have within ecosystems. The loss or addition of species in an ecosystem can provide valuable insights into the overall health and productivity of that system.