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Wetland Diatom Assemblages as Indicators of Flooding Influence and Surrounding Landuse in the Willamette Valley, OR
Author(s) -
Weilhoefer C. L.,
Pan Y.
Publication year - 2003
Publication title -
journal of phycology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.85
H-Index - 127
eISSN - 1529-8817
pISSN - 0022-3646
DOI - 10.1111/j.0022-3646.2003.03906002_170.x
Subject(s) - wetland , diatom , floodplain , species richness , environmental science , ecology , abundance (ecology) , hydrology (agriculture) , indicator species , fragilaria , land use , biology , habitat , phytoplankton , geology , nutrient , geotechnical engineering
The objective of this study was to examine the influences of the adjacent river and surrounding landuse on wetland diatom distributional patterns. Diatoms were identified in surface sediment samples from 35 riverine‐impounded wetlands within the Willamette Valley, OR. A total of 221 species were identified and no single species dominated the assemblage at all sites. Diatom richness was high throughout the area (median 71, range 66–75). The Araphidineae:Centrales index, a measure of periphytic to planktonic species ratio, was lowest at sites within the river's annual floodplain zone. A low A:C index is to be expected at wetlands that receive inputs of river planktonic species through regular flooding by adjacent large rivers. Surrounding landuse can confound the influence of riverine flooding on wetland diatom assemblages by influencing water quality. Relative abundance of the two most common species, Aulacoseira crenulata and Fragilaria capusina related negatively to % agricultural landuse surrounding the wetland. These results indicate that riverine wetland diatom assemblages may be influenced by flooding from adjacent rivers and surrounding landuse and therefore wetland sediment diatoms might serve as useful indicators of both historical environmental changes in nearby large rivers and surrounding watersheds.