Estimating altitude in distribution records of Amphibians and Reptiles: A comparative study between topographic maps and Remote Sensing data

Abstract

Altitude is an important factor when explaining species distributions. However, many biogeographical studies register altitude directly through topographic maps; a time-consuming manual process prone to mistakes. Currently, GIS and DEMs allow this work to be done more efficiently. Two methods for registering altitude for locations of amphibians and reptiles in the Iberian Peninsula were compared in order to evaluate their efficiency and similarity: manually through topographic maps, and automatically with a GIS, where two DEMs were analysed: the SRTM DEM and a DEM generated through topographic maps. The SRTM altitudes were similar to those recorded by the manual method (only Rana perezi presented differences), whereas the other DEM had differences in almost all amphibians and three reptiles. The differences between both DEMs corresponded mostly to rivers and band effect of radar sensor. The GIS method was faster, efficient and no time was consumed in searching and correcting human errors. © 2008 Brill Academic Publishers.