Spatial distributions of small water body types in modified landscapes: lessons from Indiana, USA

Because of their large numbers and biogeochemical activity, small water bodies (SWB), such as ponds and wetlands, can have substantial cumulative effects on hydrologic, biogeochemical and biological processes, yet the spatial distributions of various SWB types are often unknown, especially in modified landscapes. Using updated National Wetland Inventory data, we compare the spatial distribution of SWB types across various ecoregions and land covers within the state of Indiana. Of 203 942 total SWB, 75% contain a permanent water feature and 80% of those SWB are classified as excavated or impounded ponds. Both underlying geology and human modifications influence SWB distributions. Wetlands are most prevalent in the agricultural Drift Plain and are larger with a greater range of sizes than man-made open water features. Small impoundment ponds dominate the southern forested region of the Interior Plateau. Analysis of variance of slopes from power law distributions confirms differences between SWB distributions in the Drift Plain and the Interior Plateau as well as differences between forested wetlands and diked and excavated open waters across ecoregions. SWB densities are lowest in the Corn Belt regions and in agriculture overall. SWB in urban lands tend to have higher median area than natural or agricultural lands and have intermediate densities. This analysis highlights the presence of hydrological modifications in SWB distributions, namely the potential legacy of wetland removal and pond creation practices in the state. Determining these modified distributions and patterns is the first step in understanding cumulative SWB influences on various ecological processes in modified landscapes. Copyright © 2015 John Wiley & Sons, Ltd.