Search ARMI Database

The chemical composition of 97 lakes and ponds in and near the Mount Zirkel Wilderness Area (MZWA) was studied during snowmelt of 1998 and 1999 to determine the magnitude of episodic acidification and the effects of acidification on amphibian reproductive success. Within the areas identified as sensitive to acidification based on granitic bedrock types, there was substantial variability in ANC that was likely related to differences in hydrologic flowpaths that control delivery of weathering products to surface waters. Many of the lakes are sensitive to acidification (summer and fall ANC< 100 eq/l), however, none of them appeared to be immediately threatened by episodic or chronic acidification. 22 ponds had minimum ANC of < 30 ueq/l, indicating that they are extremely sensitive to acidic deposition, however net acidity (ANC < 0) was not measured in any of the ponds. The lowest measured pH value was 5.4 and pH generally remained less than 6.0 throughout early summer in the most sensitive ponds, indicating that biological effects of acidification are possible at levels of atmospheric deposition measured during the study.

The amount, chemical composition, and source of dissolved organic carbon (DOC), together with in situ ultraviolet (UV-B) attenuation, were measured at 1–2 week intervals throughout the summers of 1999, 2000, and 2001 at four sites in Rocky Mountain National Park (Colorado). Eight additional sites, four in Sequoia and Kings Canyon National Park/John Muir Wilderness (California)and four in Glacier National Park (Montana), were sampled during the summer of 2000.

Our objectives in this chapter are to 1) review current information on physical stressors on amphibian population declines, 2)address the roles that changes in the physical environment could play in amphibian declines, 3) make predictions about the effects of physical stressors, and 4) determine what information is needed to evaluate the effects of physical stressors on amphibian populations.

Vernal pools are sensitive environments that provide critical habitats for many species, including amphibians. In 2005 and 2006, water samples were collected from vernal pools and adjacent flowing waters in Parks in Iowa, Washington, D.C., and Maryland, prior to and just after the local use of glyphosate. Results indicate that vernal pools and adjacent streams can be contaminated by the use of herbicides within Parks to control weeds in cropped areas or noxious or nonindigenous plants. Contamination also originates from pesticide use occurring outside Park boundaries.

Amphibians occupy a range of habitats throughout the world, but species richness is greatest in regions with moist, warm climates. The objectives of this research were to model the statistical relations of anuran and caudate species richness with mean annual climate for the conterminous U.S., and to compare the strength of these relations at national and regional levels. Model variables were calculated for county and subcounty mapping units, and included 40-year (1960-99) annual mean and mean annual climate statistics, mapping unit average elevation, mapping unit land area, and estimates of anuran and caudate species richness. Climate data were derived from more than 7,500 first-order and cooperative meteorological stations and were interpolated to the mapping units using multiple linear regression models. Anuran and caudate species richness were calculated from the U.S. Geological SurveyNULLs Amphibian Research and Monitoring Initiative (ARMI) National Atlas for Amphibian Distributions. The national multivariate linear regression (MLR) model of anuran species richness had an adjusted coefficient of determination (R2) value of https://0.64 and the national MLR model for caudate species richness had an R2 value of https://0.45. Stratifying the U.S. by coarse-resolution ecological regions provided models for anurans that ranged in R2 values from https://0.15 to https://0.78. Regional models for caudates had R2 values ranging from https://0.27 to https://0.74. In general, regional models for anurans were more strongly influenced by temperature variables, while precipitation variables had a larger influence on caudate models.

We evaluated the potential toxicity of environmental mixtures of 5 classes of pesticides using concentrations from water samples collected from 50 sites on midwestern streams. Results indicated that some samples had probable toxicity to duckweed and green algae, but few are suspected of having significant toxicity to bluegill sunfish or chorus frogs.

Vernal pools are sensitive environments that provide critical habitats for many species, including amphibians. In 2005 and 2006, water samples were collected from vernal pools and adjacent flowing waters in Parks in Iowa, Washington, D.C., and Maryland, prior to and just after the local use of glyphosate. Results indicate that vernal pools and adjacent streams can be contaminated by the use of herbicides within Parks to control weeds in cropped areas or noxious or nonindigenous plants. Contamination also originates from pesticide use occurring outside Park boundaries.

Natural history note

Appendix to monitoring manual