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Changes to herbaceous plant communities on a regulated desert river
Author(s) -
Beauchamp Vanessa B.,
Stromberg Juliet C.
Publication year - 2008
Publication title -
river research and applications
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.679
H-Index - 94
eISSN - 1535-1467
pISSN - 1535-1459
DOI - 10.1002/rra.1078
Subject(s) - edaphic , herbaceous plant , riparian zone , environmental science , vegetation (pathology) , species richness , arid , ecology , abundance (ecology) , grassland , wetland , plant community , hydrology (agriculture) , soil water , habitat , geology , soil science , biology , medicine , geotechnical engineering , pathology
Riparian plant communities are shaped by gradients of disturbance intensity and frequency and resource availability. Reservoir operation can alter the composition and abundance of riparian vegetation by changing the flood regime and by trapping fine sediments and associated nutrients within the reservoir system. We examined differences in herbaceous species richness, abundance and composition in Populus‐Salix stands along an unregulated and regulated reach of a river in semi‐arid Arizona, contrasted flood inundation frequency and edaphic conditions (soil moisture, nutrients and texture) between the reaches, and interpreted the vegetation differences in light of observed differences in environmental conditions. Flooding frequency was similar between reaches, but the proportion of fine textured soils in the unregulated reach was nearly double that of the regulated reach and soil nutrient levels were up to three times higher in the unregulated reach. Herbaceous cover and richness were consistently lower in the regulated reach, with between‐reach differences greatest during dry seasons. These patterns suggest that an edaphic‐based change in resource availability is the principal pathway by which river damming is altering herbaceous vegetation in this system. Our results demonstrate that sediment transport within riparian corridors is important for maintenance of herbaceous communities and that restoration of flow regimes alone may be insufficient to restore herbaceous flora on some regulated reaches. Copyright © 2008 John Wiley & Sons, Ltd.