Spatial estimation of air temperature differences for landscape-scale studies in montane environments

Capturing fine-grain environmental patterns at landscape scales cannot be accomplished easily using conventional sampling techniques. Yet increasingly, the landscape is the scale at which ecosystems are managed. Temperature variability is an important control of many ecological processes. Elevation is often used as a proxy for temperature in montane ecosystems, partly because few direct measurements are available. We propose a low-cost and logistically practical approach to collecting spatially explicit temperature data using a network of portable temperature micro-loggers. These data can be used to generate simple, site-specific models for estimating temperature differences across complex terrain. We demonstrate the approach in a predominantly old-growth watershed in the Oregon Western Cascades. Environmental lapse rates are generated for July mean, maximum and minimum temperatures. Temperature estimates are improved substantially over these lapse rate estimates by including measures of relative radiation and relative slope position as additional explanatory variables in the model. The development of temperature estimates that explicitly account for topography has important implications for ecological analysis, which frequently relies upon the simplifying assumptions associated with lapse rates in describing the environmental template.