Riverine biodiversity in space and time: Effects of network position and hydrologic variation Travis M. Apgar, University of California- Berkeley;Michael Bogan, University of Arizona/SNRE;Shang Gao, University of Oklahoma;David Herbst, UC Santa Barbara/SNARL;Brian Gill, University of Arizona;Rose Mohammadi, University of California- Berkeley;Albert Ruhi, University of California, Berkeley;