Distribution and habitat characteristics of aquatic snails in the Iowa Great Lakes
Anna Belyaeva, GIS Certificate Candidate, Department of Ecology, Evolution and Organismal Biology
Advisor: Dr. van der Valk
Abstract: he aquatic snails of the Iowa Great Lakes were first studied in 1890, and their conditions were last updated in 1980. The previously noticeable alterations in snails’ densities and composition were attributed to the changes in lakes’ water quality. The current survey of aquatic macroinvertebrates, including snails, was conducted in 2010-2012 on Big Spirit, West Okoboji, East Okoboji, and Lower Gar Lakes before the establishment of the invasive zebra mussel. This survey includes data on species composition and densities, sediment types, and sampling depths. The stratified random sampling was employed: macroinvertebrate samples were randomly collected from three lake zones that were defined a priory. Sampling locations (45 per lake) were recorded with a GPS unit, and digitized maps were used for lake contouring. The objective of this research is to examine the depth and sediment preferences of several species of snails. The regression analysis will be employed to determining within lake factors affecting the distribution of snails. The proposed GIS application is to create snails’ density maps based on 30 and 45 samples and compare their misclassification. The interpolation of the surfaces will be conducted by the original Kriging method with ArcGIS Spatial Analysist tool.