A multiscale investigation of factors influencing local biophysical conditions within headwater streams of the Missouri Ozarks.

摘要

Riparian zones play an important role in regulating the physical, chemical, and biological character of streams, but have been severely degraded throughout much of the U.S. In Missouri, and much of the eastern U.S., most land is privately owned and small landholdings are the norm. These small landholdings, coupled with voluntary management programs, have led to localized and fragmented riparian management. There is conflicting evidence as to whether local (∼100-300 m) riparian management leads to improvements in biological integrity. The goal of my project was to evaluate the relative influence of local riparian conditions versus watershed and broader mainstem conditions on the biophysical character of Ozark headwater streams. Results show that local riparian conditions do influence local biophysical conditions within the adjacent stream. Results also show that conditions within the watershed cannot be ignored. Efforts directed at reducing maximum temperatures and fine sediment inputs are particularly important. Exclusion of cattle should result in measurable improvements in biophysical conditions, however, establishing or maintaining a mature forested corridor is equally, if not, more important. Riparian management should focus on the structural character and quality of riparian vegetation, rather than the width of the riparian corridor.