Landscape Position Project: Mollusks

Benthic invertebrate assemblages of 35 lakes surveyed for PhD dissertation of David B Lewis, conducted at the Center for Limnology, University of Wisconsin-Madison. A subset of these data was used in conjunction with the Landscape Position Project.Lakes were selected to provide gradients of landscape position within a variety of multi-lake catchments, where lakes within a catchment are linked by unidirectional groundwater and surface water flow. Within a lake, snail samples were collected from several randomly selected sites of each of four habitats: sand, cobble, coarse woody debris, and submerged vegetation. Vegetation was sampled by sweeping a standardized area with a D-net and sampled other habitats using time search and SCUBA. Complete sampling details are published in Lewis and Magnuson (2000, Freshwater Biology, 43:409-420).Sampling Frequency: each lake sampled once; sampling done during July and August of 1997-1999Number of sites: 35 lakes, including 5 LTER primary study lakes (non-bog lakes); 5-20 sites per lake depending on habitat availabilit