Published research confirms downstream export of terrestrial carbon from headwaters, but few studies exist on the volume of carbon storage along stream riparian corridors. To address this knowledge gap, researchers from the Rocky Mountain Research Station and Colorado State University measured the spatial distribution of carbon pools along different valley types of headwater streams in Rocky Mountain National Park, Colorado. Estimates of riverine carbon storage represent a previously undocumented but important carbon sink.
Results indicated that not all mountainous rivers rapidly exported carbon, and not all valley segments were equally important in carbon storage. Researchers found that low-gradient, broad valley bottoms with old-growth forest or active beaver colonies store the majority of above- and below-ground carbon. Laterally unconfined valley segments constituted <25% of total river length, but stored ~75% of the carbon. Floodplain sediment and coarse wood dominated carbon storage. Results also suggest that historical changes in riverine complexity have likely reduced carbon storage.
These findings highlight the importance of headwater streams and associated riparian areas in watershed scale carbon retention. Management to reduce effects of climate warming on headwater river corridors is important for maintaining ecosystem services such as carbon storage in mountainous watersheds.