Streams and rivers represent less than 0.0001% of the planet's water, but are support up to 10% of its biological diversity and are fundamental to human life. As sources of drinking water, transportation, recreation, and energy, streams are both highly valuable and highly vulnerable to us. Humans have obvious imperative to protect stream ecosystems, but many effects are likely to be unintentional and unseen, incidental to our existing in a place. We sampled stream macroinvertebrate communities at sites across West Marin County, California to examine how these communities change closer and farther away from human infrastructure. We find that streams closer to human populations and infrastructure host lower species richness than streams farther away, revealing impacts of our presence and activity even in an area that prides itself culturally on environmental consciousness and good stewardship. Interestingly, there were no consistent compositional differences between streams near and far from us, just fewer species supported overall. Macroinvertebrates are commonly used as 'indicators' for stream ecology and management, the presence and absence of particular orders and families indicative of more general stream quality, but here we find no such effects. Rather, each human-proximal system shows a unique combination of fewer species than in the remote sites. Our effects on the ecosystems around us can be glaring and straightforward, but as we find in wooded Marin County streams, they can also be subtle and complex., CEC Research Volume 1, Issue 1