“…Spatial patterns are the result of various processes that act on different spatial scales, and the occurrence of a species is the outcome of the combined influence of local environmental characteristics and large-scale geographical factors (Stevenson, 1997;Gombeer et al, 2011). Direct effects stem from aquatic habitat conditions related to temperature, altitude, catchment geology, hydromorphology, water quality, discharge, and substrate (Richards and Host, 1994) and indirect effects from shifts in primary (e.g., benthic algae) and secondary producers (e.g., fish; Richards and Host, 1994;Wang and Stevenson, 2005).…”