Only one known population remains in Washington in Grant County, and there is limited information about population status and trends. Efforts are underway to determine the feasibility of translocations of these frogs to their former range.
Description and Range
The northern leopard frog is a medium to large (3 to 4 inches in length) aquatic frog with a slender body, thin waist, long legs and smooth skin. The dorsal (top) color is brown or green with distinct round or oval dark spots in two to three irregular rows. The spots typically have a light border. The belly is cream or white with no markings. Learn more about how to identify this species and more information in the Washington Herp Atlas.
Ecology and life history
Northern leopard frogs are semi-aquatic, requiring aquatic and terrestrial habitats. They typically overwinter under water, but are primarily terrestrial during summer months. Northern leopard frogs require deep, well-oxygenated water that does not freeze solid for hibernation. Invasion by non-native vegetation and tall emergent encroachment through wetland succession reduces exposed shoreline, limiting the availability of suitable habitat for breeding and foraging.
Northern leopard frogs require deep, well-oxygenated water that does not freeze solid for hibernation. Northern leopard frogs require unique breeding, foraging, and overwintering habitats in close proximity due to their limited dispersal ability. In summer, northern leopard frogs forage throughout moist areas, including meadows, fields, irrigation ditches, and scrublands.
They forage predominately for insects in moist areas. In summer, northern leopard frogs forage throughout moist areas, including meadows, fields, irrigation ditches, and scrublands.
Breeding occurs in shallow, still water areas exposed to sunlight with short, emergent vegetation for egg mass attachment. During late spring, males attract females to breeding ponds by vocalizing.
A grapefruit-sized egg mass is deposited just below the water surface and attached to vegetation in warm, shallow, open, still water areas. Eggs may hatch within a few days or weeks depending on conditions. Tadpoles forage mainly on algae and detritus, and complete metamorphosis in 60 to 90 days. Newly metamorphosed frogs emerge from ponds in mid-July through September.
Invasion by non-native vegetation and tall emergent encroachment through wetland succession reduces exposed shoreline, limiting the availability of suitable habitat for breeding and foraging.
Northern leopard frogs may be preyed on by many species throughout their life history, but the most common are likely mustelids, bullfrogs, and fish.
This species has experienced range-wide declines throughout the western states and Canada. Historically, northern leopard frogs were found throughout eastern Washington, and 17 occupied sites were recognized throughout the Columbia, Crab Creek, Pend Oreille, Snake, Spokane, and Walla Walla river drainages.
The last known population of northern leopard frogs in Washington occupies the North Potholes Reservoir Unit of the Columbia Basin Wildlife Area in the Crab Creek drainage. This area has been designated the Northern Leopard Frog Management Area (NLFMA). Bullfrog colonization and fish entry to the NLFMA by surface water connections during spring flooding increases predation vulnerability. Ideal northern leopard frog habitat would be bullfrog and fish free.
Sensitivity to climate change
Limited information existsregarding the sensitivity of Northern leopard frogs to climate change. They may experience some sensitivity to potential increases in temperature, which could lead to earlier timing of mating and breeding. Their sensitivity will be increased by potential climate-induced changes in their pond habitat. Adults need deep water, seasonal ponds, and wetlands for breeding habitat and potential warmer, drier conditions could lead to declines in available breeding habitat. Non-breeding active season habitat for Northern Leopard Frog consists of herbaceous riparian habitat with sufficient surface moisture; this habitat, which is likely the most vulnerable to climate change because of more extreme summer drying, is likely to affect Northern Leopard Frog choices of non-breeding active season habitat, especially during summer conditions - where more severe contraction of that habitat is anticipated. Whether Northern Leopard Frogs might then utilize aquatic habitat more frequently during this season is unclear. It is also unclear how such a shift might exposure NLF to a different predator set. Drier conditions could even lead to localized population extinctions if breeding ponds become too shallow or disappear completely.
Exposure to climate change
- Increased temperatures
- Changes in precipitation
- Altered hydrology >Reduction in non-breeding active season habitat in summer
Conservation Threats and Actions Needed
- Invasive and other problematic species
- Threat: Non-native aquatic species including American bullfrogs, mosquito fish and other non-native fish. Bullfrogs are predatory for all life stages of northern leopard frogs.; mosquito fish prey on amphibian egg masses and tadpoles.
- Action Needed: 1. Remove mosquito fish from ponds previously occupied by northern leopard frogs. 2. Prevent introduction of non-native fish to ponds occupied by northern leopard frogs. 3. Manage habitat to favor this frog but not favor bullfrogs and fish (example, create seasonal ponds). 4. Create and maintain barriers such as dikes that prevent non-native fish from entering ponds occupied by this species.
- Threat: Unknown impacts to population from disease.
- Action Needed: Additional disease monitoring is necessary to determine the extent of the disease threat in the Northern Leopard Frog Management Area on the Columbia Basin Wildlife Area.
- Threat: Wetland succession and tall emergent vegetation encroachment (example, reed canary grass, phragmites, and non-native cattails) reduces suitability of habitat.
- Action Needed: Set back succession, reduce tall emergent vegetation and encourage short emergent cover through chemicals and mechanical treatments.
- Fish and wildlife habitat loss and degradation
- Threat: Loss of suitable habitat due to water management in the Potholes Reservoir (drawdowns, backups).
- Action Needed: Create and restore breeding habitat (seasonal ponds).
- Agriculture and aquaculture side effects
- Threat: The Odessa Supplemental Feed Route will influence water levels in Potholes Reservoir and may impact the amount of suitable habitat in the Northern Leopard Frog Management Area on the Columbia Basin Wildlife Area.
- Action Needed: 1. Maintain suitable habitat to allow for dispersal and movement. 2. Monitor population. 3. Pursue opportunities to establish new populations. 4. Use adaptive management to deal with the high level of uncertainty regarding potential habitat changes.
See the Climate vulnerability section for information about the threats posed by climate change to the northern leopard frog.