Biodiversity of Headwater Streams Under Different Forest Practices

The imprints of forest harvesting around headwaters are seen locally and downstream. Headwater streams are perhaps the most vulnerable parts of the fluvial network to changes in the surrounding environment.  The coupling with the riparian forest and upslope are very direct and yet these streams usually receive the least protection from forestry.  Riparian canopy removal can result in shifts of the thermal regime, loss or shifts of organic matter inputs, etc., and can reduce the capabilities of these habitats.  Many species are found primarily in headwaters including species of fish flies, caddisflies, amphibians and others.  In some regions, including the Pacific Northwest, headwaters have species capable of surviving in conditions with almost no surface flow for periods in the summer, and sometimes there are very high densities of those species.  The hypotheses for higher numbers include refuge from predation and higher retention of organic matter.  The species capable of surviving in headwater streams are still poorly known as typical survey methods do not always reflect the actual community.  In terms of management, even small buffers left along headwaters provide a modest level of protection to these ecosystems and may contribute to the climate-proofing of stream networks.