Non-random perch selection by cryptic lizards,Amphibolurus muricatus

Behavioral Ecology and Sociobiology - Animals are often confronted with more sensory stimuli than they can attend to, and so should pay attention to stimuli that are relevant to them and habituate...     

QUANTIFYING MODEL OUTPUT UNCERTAINTY DUE TO SPATIAL VARIABILITY OF RAINFALL1

Traditionally in the application of hydrologic/water quality (H/WQ) models, rainfall is assumed to be spatially homogeneous and is considered not to contribute to output uncertainty. The objective of this study was to assess the uncertainty induced in model outputs solely due to rainfall spatial variability. The study was conducted using the AGNPS model and the rainfall pattern captured by a network of 17 rain gauges. For each rainfall event, the model was run using the rainfall captured by each rain gauge, one at a time, under the assumption of rainfall spatial homogeneity. A large uncertainty in the modeled outputs resulted from the rainfall spatial variability. The uncertainty in the modeled outputs exceeded the input rainfall uncertainty. Results of this study indicate that spatial variability of rainfall should be captured and used in H/WQ models in order to accurately assess the release and transport of pollutants. A large uncertainty in the model outputs can be expected if this rainfall property is not taken into account.     

Cosmogenic 7Be deposition in North Wales: 7Be concentrations in sheep faeces in relation to altitude and precipitation

Beryllium-7 (7Be) is a cosmogenic radionuclide with a half-life of 53.3 days produced mostly in the stratosphere by cosmic ray spallation of nitrogen and oxygen and entering the lower troposphere by atmospheric circulation processes. Most of the nuclide is removed by rainout during precipitation, so given that rainfall generally increases with altitude, it was considered probable that 7Be deposition would also be greater at higher altitudes. The aim of this study was to determine if there is any relationship between 7Be concentrations, altitude and precipitation by measuring 7Be activity within sheep faeces. An area of North Wales and Northwest England was selected for study, extending from the Dee Estuary at sea level to Snowdon at 1065 m. The results obtained showed a significant increase in 7Be activity with increasing altitude and precipitation consistent with predictions based on the existing literature.