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
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Glyphosate and its degradation product AMPA occur frequently and widely in U.S. soils, surface water, groundwater, and precipitation
Author: Battaglin W, Meyer M, Kuivila K, Dietze J | Date: 2014 | Outlet: Journal of the American Water Resources Association 50(2): 275-290. | Format: URL
Glyphosate use in the US increased from less than 5,000 to more than 80,000 metric tons per year between 1987 and 2007. Glyphosate is popular due to its ease of use on soybean, cotton and corn crops that are genetically modified to tolerate it, utility in no-till farming practices, utility in urban areas, and the perception that it has low toxicity and little mobility in the environment. This compilation is the largest and most comprehensive assessment of the environmental occurrence of glyphosate and AMPA in the US conducted to date, summarizing the results of 3,732 water and sediment and 1,018 quality-assurance samples collected between 2001 and 2010 from 38 States. Results indicate that glyphosate and AMPA are usually detected together, mobile, and occur widely in the environment. Glyphosate was detected without AMPA in only 2.3% of samples, whereas AMPA was detected without glyphosate in 17.9% of samples. Glyphosate and AMPA were detected frequently in soils and sediment, ditches and drains, precipitation, rivers, and streams; and less frequently in lakes, ponds, and wetlands; soil water; and groundwater. Concentrations of glyphosate were below levels of concern for humans or wildlife; however, pesticides are often detected in mixtures. Ecosystem effects of chronic low-level exposures to pesticide mixtures are uncertain. The environmental health risk of low-level detections of glyphosate, AMPA, and associated adjuvants and mixtures remain to be determined.
The effects of hydropattern and predator communities on amphibian occupancy
Authors: Amburgey S, Bailey L, Murphy M, Muths E, Funk W | Date: 2014-09-23 | Outlet: Canadian Journal of Zoology | Format: URL
Complex, interactive ecological constraints regulate species distributions, and understanding these factors is crucial for predicting species persistence. We used occupancy analysis, which corrects for imperfect detection, to test the importance of abiotic and biotic habitat and landscape factors on probability of occupancy by boreal chorus frog (Pseudacris maculata; Agassiz 1850) tadpoles. We hypothesized that hydropattern and predators are primarily important as they affect desiccation and predation risk and can interact in ways difficult to predict. We surveyed 62 wetland sites across an elevational gradient in Colorado, USA and modeled patterns in P. maculata occupancy. Tadpoles were most frequently present in intermediate hydropattern systems with lower desiccation risk and no predatory fish due to occasional drying. P. maculata occupancy had a strong negative relationship with fish presence while tadpoles, odonate larvae and tiger salamanders (Ambystoma mavortium; Baird 1850) frequently co-occurred. Dry seasonal conditions will likely result in fewer intermediate hydropattern ponds available for amphibian breeding. We hypothesize that this will force P. maculata to breed in habitats with fish. As habitats shrink, predators that co-occur with P. maculata are expected to concentrate in the remaining habitat and increase predation risk for developing tadpoles (assuming predators are similarly constricted in their habitat use as amphibians are).
Detecting Emergence, Growth, and Senescence of Wetland Vegetation with Polarimetric Synthetic Aperture Radar (SAR) Data.
Authors: Gallant AL, Kaya SG, White L, Brisco B, Roth MF, Sadinski W, Rover J | Date: 2014-03-24 | Outlet: Water. 2014; 6(3):694-722 | Format: .PDF
Wetlands provide ecosystem goods and services vitally important to humans. Land managers and policymakers working to conserve wetlands require regularly updated information on the statuses of wetlands across the landscape. However, wetlands are challenging to map remotely with high accuracy and consistency. We investigated the use of multitemporal polarimetric synthetic aperture radar (SAR) data acquired with Canadaís Radarsat-2 system to track within-season changes in wetland vegetation and surface water. We speculated, a priori, how temporal and morphological traits of different types of wetland vegetation should respond over a growing season with respect to four energy-scattering mechanisms. We used ground-based monitoring data and other ancillary information to assess the limits and consistency of the SAR data for tracking seasonal changes in wetlands. We found the traits of different types of vertical emergent wetland vegetation were detected well with the SAR data and corresponded with our anticipated backscatter responses. We also found using data from Landsatís optical/infrared sensors in conjunction with SAR data helped remove confusion of wetland features with upland grasslands. These results suggest SAR data can provide useful monitoring information on the statuses of wetlands over time.