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To link to full-text access for this article, visit this link: http://dx.doi.org/10.1016/j.anbehav.2004.10.017 Byline: Adam J. Leavesley, Robert D. Magrath Abstract: Vertebrate flee alarm calls can provide information about the type of predator, and some mammalian alarm calls also appear to communicate the degree of danger and therefore urgency of escape. However, because predators are usually rare, it has proved difficult to obtain observations differing only in the degree of danger, or to record sufficient naturally provoked alarm calls for fully replicated playback experiments. In this study, we took advantage of a system in which the major aerial predator was common, allowing repeated, matched observations of natural interactions between predator and prey, combined with a fully replicated playback experiment. We found that the aerial trill alarm call of the white-browed scrubwren, Sericornis frontalis, varied according to the distance from the suddenly appearing predator: the closer the predator, the greater the number of elements in the call and the higher their minimum frequency (pitch). Playback experiments showed that multi-element alarm calls prompted a more urgent response, including immediate fleeing to cover. Furthermore, the response was graded, such that an alarm with more elements provoked a more urgent response. Our study therefore isolated the effect of predator distance on alarm call design, and showed that individuals respond appropriately to calls in the absence of any other cues. To our knowledge, this is the most explicit demonstration that avian flee alarm calls can convey urgency. Author Affiliation: School of Botany and Zoology, Australian National University, Canberra, Australia Article History: Received 25 February 2004; Revised 29 March 2004; Accepted 30 October 2004 Article Note: (miscellaneous) MS. number: 8026

Spectral indices derived from satellite optical remote sensing data have typically been used for fire severity estimation, although other remote sensing systems such as Light Detection and Ranging (LiDAR) are increasingly applied. Despite a multitude of remotely sensed fire severity estimation methods, comparisons of method performance are few. Insights into the merits and limitations of remotely sensed fire severity methods help develop appropriate spatial tools for the management of fire-affected areas. We evaluated the performance of seven passive (optical) and active (LiDAR) remotely sensed fire severity estimation methods in classifying and explaining variation in a field-estimated modified Composite Burn Index (MCBI) for a recent large wildfire in south-eastern Australia. Our evaluation included three commonly applied indices; the differenced Normalized Burn Ratio (dNBR), Relative dNBR (RdNBR) and Relative Burn Ratio (RBR). We compared these NBR indices against two recently proposed fire severity estimation methods that have not previously been evaluated with CBI field data – the Vegetation Structure Perpendicular Index (VSPI) spectral index and the LiDAR point cloud-derived Profile Area Change (PAC), along with experimental relativized forms of these indices (RVSPI and RPAC, respectively). The RVSPI (κ = 0.47) demonstrated similar overall classification accuracy (N classes = 4) to the PAC (κ = 0.48), however both indices had lower classification accuracy than the dNBR (κ = 0.59), RdNBR (κ = 0.59) and RBR (κ = 0.61). The VSPI and PAC were unable to accurately represent non-structural changes caused by lower severity fire. Application of these optical and LiDAR indices should consider their discussed limitations in relation to the objectives of their application. [ABSTRACT FROM AUTHOR]