Novel anthropogenic noise has received considerable attention in behavioral ecology, but natural acoustic environments have largely been ignored as ecological niche axes. In riparian sites, within an arid sagebrush steppe ecosystem, we use a natural range of acoustic environments along with experimentally broadcasted whitewater river noise to test our hypothesis that river noise is an important niche axis. We show that orb-weaving spiders (Araneidae and Tetragnathidae) are more abundant in high sound level environments, but do not seem to be affected by the background noise spectrum. We explore multiple hypotheses for these patterns, such as loss of vertebrate predators and increased prey capture, and then assess how web-building behavior and body condition may be altered. Here, we demonstrate that river noise has the potential to alter spider abundance and behavior.