Ostracodes as Hydrologic Indicators in Springs, Streams and Wetlands: A Tool for Environmental and Paleoenvironmental Assessment

Although the majority of publications on extant nonmarine ostracode species in North America are concerned with lacustrine settings, many species that are potentially valuable as indicators of water quality changes live in non-lacustrine settings. Ostracode distributions in 157 springs, wetlands and streams in the United States are examined here in order to assess 1) species richness, 2) association with physical and chemical parameters of their habitats and 3) the presence of potentially useful biomonitors and environmental sentinels. The 157 non-lacustrine sites are a subset of a large database (North American Non-marine Ostracode Database: NANODe version 1) consisting of 611 mostly lacustrine sites with ostracode species, presence-absence data, hydrochemistry and climate data (Forester et al., in review). Of the 89 species represented in NANODe version 1, 51 species are found in springs, 59 species are found in wetlands and only 15 species are found in streams. Many species are found in at least two of these habitats and some in all three. Principal Components Analysis of these 157 sites indicates that 71% of the variance is explained by salinity (total ionic concentration), alkalinity and temperature, a result consistent with previously published analyses of natural water. Cluster analysis shows that spring species are most strongly tied to temperature, whereas wetlands and streams are most strongly tied to ionic composition. Three species are found to be potentially valuable biomonitors: Cavernocypris wardi in springs, Fabaeformiscandona rawsoni in wetlands and Physocypria globula in streams.