K. Jones (USGS) extracting a water sample for pesticide analysis at Pesticide Fate Research Laboratory. Photo by: R. Todd.
The collaborative design which joins wildlife biologists and hydrologists enables ARMI to ask the kinds of questions it does about the environmental variables that affect amphibians in a truly integrated manner. Understanding how water quality, quantity, or timing affects amphibians is a critical component of ARMI research.
A hydrologist is associated with each ARMI region and works with the ARMI PI to develop and implement research and monitoring projects. These collaborations enable ARMI to ask questions about how water quality (e.g., nutrients, agro-chemicals, acidification), water budgets (e.g., ground and surface water models), storm surge impacts, or other hydrologic conditions can affect amphibian life cycles, disease transport, or habitat quality.
USGS Toxics Substances Hydrology program
ARMI Products on Water
* USGS neither sponsors nor endorses non-USGS web sites; per requirement "3.4.1 Prohibition of Commercial Endorsement."
* PDF documents require Adobe Reader or Google Chrome Browser for viewing.
Amphibians in the climate vice: loss and restoration of relilience of montane wetland ecosystems of the American West
Authors: Ryan ME, Palen WJ, Adams MJ, Rochefort RM | Date: 2014-05-01 | Outlet: Frontiers in Ecology and the Environment 12:232-240
Wetlands in the remote mountains of the American West are the site of two massive ecological “experiments” spanning the 20th Century. In a kind of biological carpet-bombing following World War II, fish and wildlife managers introduced millions of predatory trout into fishless mountain ponds and lakes across the Western United States. The new top predators, which now occupy 95% of large mountain lakes, have truncated the habitat distributions of native frogs, salamanders, and wetland invertebrates to smaller, more ephemeral ponds where fish do not survive. Now a second “experiment” –anthropogenic climate change – threatens to push from the opposite direction; eliminating many ephemeral habitats and shortening wetland hydroperiods. Caught between climate-induced habitat loss and predation from introduced fish, native mountain lake fauna of the American West – especially amphibians– are at risk of being squeezed out. Targeted fish removals, guided by models of wetlands change, provide new strategies for restoring resilience.
Population-level thermal performance of a cold-water ectotherm is linked to ontogeny and local environmental heterogeneity
Authors: Hossack BR, Lowe WH, Webb MAH, Talbott MJ, Kappenman KM, Corn PS | Date: 2013-11 | Outlet: Freshwater Biology 58:2215-2225 | Format: .PDF
1. Negative effects of global warming are predicted to be most severe for species that occupy a narrow range of temperatures, have limited dispersal abilities, or have long generation times. These are characteristics typical of many species that occupy small, cold streams.
2. Habitat use, vulnerabilities and mechanisms for coping with local conditions can differ among populations and ontogentically within populations, potentially affecting species-level responses to climate change. However, we still have little knowledge of mean thermal performance for many vertebrates, let alone variation in performance among populations. Assessment of these sources of variation in thermal performance is critical for projecting the effects of climate change on species and for identifying management strategies to ameliorate its effects.
3. To gauge how populations of the Rocky Mountain tailed frog (Ascaphus montanus) might respond to long-term effects of climate change, we measured the ability of tadpoles from six populations in Glacier National Park (Montana, USA) to acclimate to a range of temperatures. We compared survival among populations according to tadpole age (age 1-yr or 2-yr) and according to the mean and variance of late-summer temperatures in natal streams.
4. The ability of tadpoles to acclimate to warm temperatures increased with age and with variance in late-summer temperature of natal streams. Moreover, performance differed among populations from the same catchment.
5. Our experiments with a cold-water species show that population-level performance varies across small geographic scales and is linked to local environmental heterogeneity. This variation could influence the rate and mode of species-level responses to climate change, both by facilitating local persistence in the face of changes in thermal conditions, and by providing thermally-tolerant colonists to neighbouring populations.
Accumulation of pesticides in Pacific chorus frogs Pseudacris regilla from California's Sierra Nevada mountains, USA
Authors: Smalling KL, Fellers GM, Kleeman PM, Kuivila KM | Date: 2013-07 | Outlet: Environmental Toxicology and Chemistry 32:2026-2034
Pesticides are receiving increasing attention as potential causes of amphibian declines, acting singly or in combination with other stressors, but limited information is available on the accumulation of current-use pesticides in tissue. The authors examined potential exposure and accumulation of currently used pesticides in pond-breeding frogs (Pseudacris regilla) collected from 7 high elevations sites in northern California. All sites sampled are located downwind of California’s highly agricultural Central Valley and receive inputs of pesticides through precipitation and/or dry deposition. Whole frog tissue, water, and sediment were analyzed for more than 90 current-use pesticides and pesticide degradates using gas chromatography–mass spectrometry. Two fungicides, pyraclostrobin and tebuconazole, and one herbicide, simazine, were the most frequently detected pesticides in tissue samples. Median pesticide concentration ranged from 13 mg/kg to 235 mg/kg wet weight. Tebuconazole and pyraclostrobin were the only 2 compounds observed frequently in frog tissue and sediment. Significant spatial differences in tissue concentration were observed, which corresponded to pesticide use in the upwind counties. Data generated indicated that amphibians residing in remote locations are exposed to and capable of accumulating current-use pesticides. A comparison of P. regilla tissue concentrations with water and sediment data indicated that the frogs are accumulating pesticides and are potentially a more reliable indicator of exposure to this group of pesticides than either water or sediment.