Abstract
During summer 2010, we conducted surveys of riparian spiders along 3, 10-m reaches separated by 10 m each. Sampling was conducted between August 12 and 14. During summer 2011, we conducted surveys of riparian spiders along five, 10-m reaches that were spaced by 10 m. Surveys took place within 3 days of one another and were conducted after dusk with high-power flashlights (Surefire, Fountain Valley, CA, USA). Each survey lasted about 1 hour per stream. We conducted monthly surveys from June to August for each of the 15 study streams. Riparian areas were left undisturbed by not walking in the riparian or up the stream for at least 24 h before surveys were conducted. Observers walked up the stream and counted all arboreal spiders on both banks above the active channel and within 1 m of the stream edge to a maximum height of 2.5 m. Spiders were identified to family on sight, which was accomplished easily based on web construction and body morphology (Ubick 2005). Although we recorded all spiders that were encountered during the surveys, we focused our later analysis on web-spinning spiders because these taxa of spiders (i.e., Tetragnathidae, Araneidae, Linyphiidae) rely more heavily on aquatic emergence. Thus, their populations can closely track emerging prey (Marzcak et al. 2007b).