Little Rock Lake - CWH Study at North Temperate Lakes LTER - Benthic Macroinvertebrates 2002 - 2004

Benthic invertebrates were collected as part of CWH (coarse woody habitat) study on
Little Rock Lake in Vilas county, WI. Pre-manipulation sampling of the macroinvertebrate
communities was conducted in the summer of 2002 before the CWH reduction and six times after
the reduction, in early, mid, and late summer (May-August) of 2003 and 2004. We divided the
shoreline of Little Rock Lake into 50 m sections and randomly chose five sections from each
basin for each separate sampling of macroinvertebrates. We collected two benthos and two CWH
macroinvertebrate samples at each section. We constructed a benthos sampler by connecting a
SCUBA tank to a 7.6 cm PVC pipe with a hose attached 10 cm from one end of the pipe (Wahle
and Steneck 1991; Roth et al. 2007). A 500 m Nitex mesh bag was place at the top end of the
pipe furthest from the attached hose. Once the tank was turned on, a vacuum formed that
sucked the benthos sample into the bag. We used a 0.09 m2 hoop to delineate the benthos
sampling area. We sampled CWH using a self-contained, battery-powered aquatic vacuum with a
500 m Nitex mesh bag (Vander Zanden et al. 2006). Sampling lasted for 30 seconds. All
samples were stored in 95% ethanol until processed. Macroinvertebrates were identified to
the lowest possible taxonomic level. Helmus M.R. and Sass G.G. (2008) The rapid effects of a
whole-lake reduction of coarse woody debris on fish and benthic macroinvertebrates.
Freshwater Biology, 53, 1423-1433 Number of sites: 44 Sampling Frequency: once
pre-manipulation, 6 sampling regimes after reduction