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RANA CATESBEIANA (AMERICAN BULLFROG) DIET
Citation:
Cross, C L. AND S. L. Gerstenberger. RANA CATESBEIANA (AMERICAN BULLFROG) DIET. HERPETOLOGICA 33(1):55-56, (2002).
Impact/Purpose:
The primary objectives of this research are to:
Develop methodologies so that landscape indicator values generated from different sensors on different dates (but in the same areas) are comparable; differences in metric values result from landscape changes and not differences in the sensors;
Quantify relationships between landscape metrics generated from wall-to-wall spatial data and (1) specific parameters related to water resource conditions in different environmental settings across the US, including but not limited to nutrients, sediment, and benthic communities, and (2) multi-species habitat suitability;
Develop and validate multivariate models based on quantification studies;
Develop GIS/model assessment protocols and tools to characterize risk of nutrient and sediment TMDL exceedence;
Complete an initial draft (potentially web based) of a national landscape condition assessment.
This research directly supports long-term goals established in ORDs multiyear plans related to GPRA Goal 2 (Water) and GPRA Goal 4 (Healthy Communities and Ecosystems), although funding for this task comes from Goal 4. Relative to the GRPA Goal 2 multiyear plan, this research is intended to "provide tools to assess and diagnose impairment in aquatic systems and the sources of associated stressors." Relative to the Goal 4 Multiyear Plan this research is intended to (1) provide states and tribes with an ability to assess the condition of waterbodies in a scientifically defensible and representative way, while allowing for aggregation and assessment of trends at multiple scales, (2) assist Federal, State and Local managers in diagnosing the probable cause and forecasting future conditions in a scientifically defensible manner to protect and restore ecosystems, and (3) provide Federal, State and Local managers with a scientifically defensible way to assess current and future ecological conditions, and probable causes of impairments, and a way to evaluate alternative future management scenarios.
Description:
RANA CATESBELANA (American Bullfrog). DIET. Data were obtained opportunistically
from 28 adult (M = 14; F = 14) bullftogs collected in April 2001 from the Meadow Valley Wash
located between the cities of Carp and Elgin, Lincoln County, Nevada, USA (N37'17':WI14'30'). Although there are two large summary reports on the bull frog that provide
publication lists of bullfrog food/diet literature (Bury and Whelan 1984. Ecology and
management of the bullfrog. USDI, FWS Resource Publ. 155. 23 pp.; Casper and Hendricks. In Press. Status and Conservation of U. S. Reptiles. M. Lannoo, Ed.), there are, to our knowledge, no published reports discussing bullfrog diets from this region. Sportsmen collected frogs using gigging techniques with the intention of removing the hind legs for consumption. After collection, frogs were assigned an identification number, weighed to the nearest gram, and measured from the tip of the snout to the vent (to the nearest millimeter). After the hind legs were removed by the sportsmen, the frogs were placed in plastic bags indicating the assigned specimen number and placed immediately on ice and transported to the laboratory. Stomachs were dissected and all contents placed in 10% formalin. As part of a related study, liver, brain, kidney, and muscle tissues were dissected and analyzed for mercury (Gerstenberger and Pearson. In Review. Mercury concentrations in bullfrogs (Rana catesbeiana) collected from a southern Nevada wetland. Bulletin of Environmental Contamination and Toxicology).