Within the critical habitat units for the California Red-Legged Frog, the primary constituent elements consist of five components:

Aquatic breeding critical habitat. Defined in 50 CFR 17.95(d)(2)(i) as standing bodies of fresh water (salinity < 7.0 parts per thousand) including: natural and manmade (e.g., stock) ponds, slow moving streams or pools within streams, other ephemeral or permanent water bodies that typically become inundated during winter rains and hold water for a minimum of 20 weeks in all but the driest years.

Non-breeding aquatic critical habitat. Defined in 50 CFR 17.95(d)(2)(ii) as fresh water habitats that may or may not hold water long enough for the frog to complete its lifecycle but that do provide for shelter, foraging, predator avoidance, and aquatic dispersal. Wetland habitats that meet these elements include, but are not limited to: plunge pools within intermittent creeks, seeps, quiet water refugia during high water flows, springs of sufficient flow to withstand summer dry periods.

Upland critical habitat. Defined in 50 CFR 17.95(d)(2)(iii) as upland areas within 200 ft of the edge of riparian vegetation or dripline surrounding aquatic and riparian habitat and comprised of vegetation such as grasslands, woodlands and/or wetland/riparian plant species that provides shelter, forage, predator avoidance for the frog. Can include natural features such as boulders, rocks, organic debris, small mammal burrow, and moist leaf litter or manmade features such as industrial debris and agricultural features.

Aquatic features. Defined as fresh-water habitats in or near lowlands or foothills with dense, shrubby, or emergent vegetation. Such areas include natural or manmade (e.g., stock) ponds, slow moving streams or pools within streams, and other ephemeral or permanent waterbodies that typically become inundated during winter rains such as plunge pools, intermittent creeks, seeps, and quiet water refugia. Such areas do not include those areas not otherwise meeting the definition of aquatic breeding habitat and non-breeding aquatic habitat.

Upland habitats. Defined as all areas that are both within 200 feet of the mean high-water mark of an aquatic feature and meet the definition of upland habitat as it applies to Critical Habitat. 

Read more about the litigation related to the California Red-Legged Frog.