Spotted Frog - Rana pretiosa
( Baird & Girard, 1853 )

 

 

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Subspecies: Unknown
Est. World Population:

CITES Status: NOT LISTED
IUCN Status: Vulnerable
U.S. ESA Status: NOT LISTED

Body Length:
Tail Length:
Shoulder Height:
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Top Speed:
Jumping Ability: (Horizontal)

Life Span: in the Wild
Life Span: in Captivity

Sexual Maturity: (Females)
Sexual Maturity: (Males)
Litter Size:
Gestation Period:

Habitat:
This species is highly aquatic and is generally associated with wetland complexes that are  >4 ha in size and contain extensive emergent marsh coverage (Pearl and Hayes 2004). Individuals usually occur at the the grassy margins of streams, lakes, ponds, streams, and marshes, and are very rarely found more than 2 m from a surface-level permanent water source ( (Licht 1971, 1986, Watson et al. 2003, Green et al. 2014). Movement among seasonal habitats usually takes place along flooded or saturated corridors (Watson et al. 2003). This species is capable of colonizing sites within at least several hundred meters of an existing population, if there is adequate riparian/wetland habitat between area (Watson et al. 2003). Adults prefer microhabitats that are characterized by deeper water and relatively open forest canopy. They remain near standing water throughout the summer season, and may also utilize seasonally temporary ponds that are within 300 m of the larger, permanent wetlands in which they breed (Green et al. 2014). Wintering sites include springs, slow-flowing channels, or deep open water (Hallock and Pearson 2001, Chelgren et al. 2008). This species breeds in shallow ponds or other quiet waters among moderate or dense herbaceous vegetation, with eggs usually laid close to the shore (Pearl et al. 2009). Egg-laying is temperature-dependent, and females begin to lay eggs when water temperatures reach approximately 6°C (Licht 1971). Breeding typically occurs in February or March at lower elevations and as late as late May or early June at higher elevations (Leonard et al. 1993). This species does not appear to adapt well to habitat disturbance or alteration, although it does occur in some anthropogenic ponds in central Oregon (C. Pearl unpubl. data). The generation length is assumed to be five years, as this is typical for the genus.

Range:
The historic range of this species spanned west of the Cascade crest from northeastern California north through Oregon and along the the eastern side of the Puget/Willamette Valley trough and the Columbia River gorge in south-central Washington up to southwestern British Columbia. It is now considered to be extirpated from the Willamette Valley, all of its range in northeastern California, and much of its range in western Washington (Hayes 1997, Pearl and Hayes 2005, Green et al. 2014). It is now known from only four extant occurrences in British Columbia, six in Washington, and about a dozen in Oregon (USFWS 2013). This species occurs at elevations ranging from sea level to 1,635 m asl (Green et al. 2014). At the northern range limits, occurrences are unlikely to occur at elevations above 200 metres (Pearl and Hayes 2004).

Conservation:
Conservation Actions
This species is somewhat protected in several federal and state parks and refuges, however for various reasons, including lack of adequate available information, management has not traditionally given much attention to this species. These areas include Billy Frank Jr. Nisqually National Wildlife Refuge, Conboy Lake National Wildlife Refuge, and Klamath Marsh National Wildlife Refuge. In British Columbia, one population occurs on lands owned by the Department of National Defence; two populations occur on private lands; and one occurs on First Nations and private lands (USFWS 2009).Some zoos in North America have raised wild-caught larvae and then reintroduced them to the wild, although captive breeding of this species has not yet been successful. A recovery strategy has been prepared for the British Columbia subpopulation and its implementation is in progress, including population monitoring and introductions of captive bred individuals to new and formally occupied sites. This species is listed as Threatened in the U.S. under the U.S. Endangered Species Act (ESA) and is considered Endangered in Canada under the Canadian Species At Risk Act (SARA) by the Committee on the Status of Endangered Wildlife in Canada (COSEWIC). 

Conservation Needed
Recommended conservation measures include improved management of the existing protected area(s) and habitat maintenance, as well as efforts to remove problematic invasive species from sites where this species occurs. Additionally, the most viable subpopulations need to be identified and protected. Assemblages of adjacent breeding sites tend to have the largest number of breeding adults per site (Pearl et al. 2009), so protection of these areas is most important. 

Research Needed
Current research needs for this species include:
  1. Coordinated range-wide monitoring of populations to determine sizes and trends;
  2. Assessment of habitat use patterns and potential impacts of projected and ongoing logging operations, mining, and other development operations across the range;
  3. Studies of potential factors causing regional declines in this species and other amphibians in general;
  4. Long-term viability analysis and development of appropriate management protocols for ensuring viable subpopulations;
  5. Further study of movement ecology is needed to improve our understanding of habitat connectivity and the effects of site isolation on the persistence of Rana pretiosa in Oregon (Pearl et al. 2009).

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