Short-Term Benthic Macroinvertebrate Response to Fire and Hydrologic Event-Induced Changes in Stream Bed Sediment in the Colorado Front Range

摘要

The effect of wildfires on forests and aquatic environments in the Colorado Front Range is relatively well understood. However, the way in which macroinvertebrate community structures change in the six months after a fire is an aspect currently lacking consensus. This study evaluates the response of benthic macroinvertebrates in the Cache la Poudre to the High Park Fire of 2012, and emphasizes the change in sediment sizes in the stream bed and how food sources may be affected. Changes in stream health and its potential impact on water quality are also considered. Comparisons were made between invertebrate communities in Boulder Creek, an unburned reference stream, and the Cache la Poudre from 2003 and 2012 to determine how taxa distributions changed. Sediment sizes were measured in both streams in November 2012, and these data were compared to sediment size data from a study conducted after the Hayman Fire of 2002. Macroinvertebrate diversity decreased in the Cache la Poudre after the fire, and stream health was slightly degraded. Sediment sizes decreased overall, and most likely impacted the availability of food for invertebrates, which may have contributed to their reduced diversity and poorer stream health.