![]() ![]() A study of Rana aurora in Oregon found an adult female frog that had moved almost 4.8 km from her known breeding pond ( 2019). The home range of breeding adults can be several kilometers. Adults are insectivores and have a longevity of >10 years (Dodd 2013). In terrestrial environments, adults can be found with coarse woody debris and in mid-level canopy trees (Aubry and Hall 1991). The total size of the tadpole before metamorphosis is 50-70 mm (total length) (Dodd 2013).Įcology: Rana aurora occupy a variety of aquatic habitats including wetlands, rivers, streams, ephemeral, and permanent ponds (Jennings and Hayes 1994). The labial tooth row formula, defined as a fraction designating the location and number of labial tooth rows, are 2/3 or 3/4 (Stebbins 2003). Small tadpoles have a light gold line along the side of the body that disappears as the tadpole grows. The dorsal and ventral tail fins have tiny dark spots and a golden tone. The tadpoles of Rana aurora are a tan to dark brown color with scattered clumps of golden flecks. Rana aurora’s call during the day or night is a very quiet weak series of 5-7 notes, sounding like uh-uh-uh-uh-uh, lasting 1-3 seconds ( 2019). A light lip-line is usually present from the eye to shoulder and boarded above by a dark mask (Dodd 2013). This red coloration is not apparent in juveniles. The frog's common name comes from the red coloration on its abdomen and undersides of its arms and legs. Moreover, the higher of the two environmentally relevant temperatures did not appear to significantly affect the surrogate species but the temperature data reveals ambiguities that merit further investigation.Identification: Rana aurora is a smooth-skinned frog with a brown, reddish-brown or greenish-gray color on its dorsal side with a peppering of small black spots. Mixed metal toxicity tests also revealed that Ni may have an ameliorating effect on Cu toxicity. In addition, the Phase II laboratory toxicity testing found that exposure to Cu and Ni, as single-metal toxicants and in combination at two environmentally relevant temperatures, have the potential to impact Cascades frog even at small concentrations. Phase I of this study revealed several metals including aluminum (Al), chromium (Cr), Ni, Cu, Zn, arsenic (As), cadmium (Cd), and lead (Pb) in breeding ponds that exceeded USEPA Criterion Continuous Concentration (CCC) and the Criterion Maximum Concentration (CMC) Water Quality Criteria (WQC) for Aquatic Life. The test organism was the locally abundant species, the Northern red-legged frog (Rana aurora), which was used as a surrogate for Cascades frog. Toxicological endpoints included: time to hatch, time to mortality, length, percent malformed, and percent survival. The metals found in the surface water samples and the SLMDs were used to inform and select metals to test in Phase II, where laboratory toxicity testing of copper (Cu), nickel (Ni), and zinc (Zn) was conducted at 20.0☌ and 22.5☌. During this Phase, surface water grab samples were collected, and stabilized liquid membrane devices (SLMDs) deployed. ![]() In Phase I, the goal was to identify and select aqueous metals present in mountain ponds during the Cascades frog breeding season to understand potential exposure levels. To explore the relationship between Cascades frog (Rana cascadae) survival, metals, and climate, a two-phase study was conducted to evaluate metals and temperature as multiple factors, and how they may affect in aquatic environments with breeding populations of Cascades frog. Risks may be especially pronounced in amphibians that reside in high-alpine aquatic ecosystems, such as the Cascades frog (Rana cascadae), which may be affected by metal contamination and climate change acting as multiple stressors. Several recent studies have addressed amphibian population declines due to climate change, yet few studies have examined the interacting effects of climate change and metal contaminants as they relate to amphibians. In the western United States, disappearances have resulted in significant range contractions due to habitat loss, climate change, predation by non-native species, pesticide use, and disease, most recently by the fungal pathogen, Batrachochytrium dendrobatidis. Amphibian populations have been declining globally since at least the 1970s. ![]()
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