Comment on "Roadless Space of the Conterminous United States"

Many widely-used metrics quantify landscape pattern. Watts et al. (Reports, 6 May 2007, p 736) propose another, roadless volume (RV). However, as with most previous metrics, RV does not explicitly address ecological processes, and can produce misleading results. We demonstrate RV can produce results inconsistent with the notion of landscape connectivity, and contend better, ecologically more relevant metrics are available.