Low-Cost Radiation Shielding for Use in Mapping the Thermal Environments of Rangeland Animals.
Authors:
Clark, P.E. Johnson, D.E. Harris, N. Thomas, D.R. USDA, ARS
Source:
Rangeland ecology & management. 2006 Nov., v. 59, no. 6, p. 674-679.
NALT Subjects:
livestock wildlife rangelands air temperature solar radiation shade spatial variation sampling data collection measuring devices costs and returns accuracy
Other Subjects:
radiation shielding data loggers materials costs
Issue Date:
Nov-2006
Abstract:
Variations in its thermal environment can influence how an animal utilizes a rangeland landscape. Mapping the spatial and temporal air temperature patterns throughout a landscape may be helpful in predicting range animal distribution and habitat use. Many sampling points are required to effectively map air temperature levels throughout extensive and topographically diverse rangelands. Self-contained air temperature data loggers are commercially available, but these require shielding from solar radiation to provide accurate measurements. Commercial shields are expensive and fragile. A low-cost, robust, and effective alternative to commercial shields is needed for air temperature mapping applications. Two types of shields, vented cylinder and inverted-U shaped, were constructed from PVC pipe. Temperature loggers protected in either of these shielding types provided more accurate air temperature measurements than unshielded loggers. Temperature measurements from loggers protected by inverted-U shields were within ±2.5°C of a reference instrument in 94.7% of 2496 observations. About 86.2% of observations acquired by loggers within vented-cylinder shields were within ±2.5°C of the reference. Conversely, only 66.1% of the measurements from unshielded loggers were within ±2.5°C of the reference. Both shielding types were designed to be attached to a swiveling mounting system, thus avoiding damage by animals and eliminating the need for protective exclosure fencing. Materials costs for constructing either shield type, including the mounting system, were $8.00 or less. In contrast, commercially available radiation shields with mounting hardware cost $75.00 or more. Compared to the use of commercial shielding, construction and deployment of these PVC-pipe shields would reduce the cost, time, and labor required to collect accurate air temperature data at many points across an extensive landscape.
