Geology Reports⌕ Search

USGS · 70011559

Stream-grade variation and riparian-forest ecology along Passage Creek, Virginia

Abstract

Passage Creek, in northwestern Virginia, flows on relatively nonresistant shales, then cuts through a gorge underlain by resistant sandstone In the gorge, the stream gradient steepens, the size of bed material increases, a braided channel forms, and riparian-forest composition and growth form changes relative to areas outside the gorge Effects of flooding are intensified within the gorge and revealed in the pattern and deformation of streamside vegetation Increased stream gradient within the gorge provides for high stream power and coarse sediment deposition relative to the flood plain outside the gorge. A more diverse upland forest grows on the flood plain in the gorge The riparian forest in the gorge may be an example of a nonequilibrium forest, resulting from periodic disturbance by destructive floods. Recognition of vegetation patterns resulting from such disturbances may be useful in detection of potential flooding.

Explore related subjects

90° N90° S · 180° W ← longitude → 180° E
Source-reported bounding extent: 38.903739942845306° to 38.9564952246742° latitude; -78.36374722152102° to -78.29175031724742° longitude. This indicates report coverage, not an exact sampling location. View area on OpenStreetMap.

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

Cliff R. Hupp. 1982. Stream-grade variation and riparian-forest ecology along Passage Creek, Virginia. https://doi.org/10.2307/2996489

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related USGS reports

More flowers or new cladodes? Environmental correlates and biological consequences of sexual reproduction in a Sonoran Desert prickly pear cactus, Opuntia engelmannii

Should a platyopuntia expend all aerolar meristems in flower production, now new cladodes could be produced, and further reproductive effort and vegetative growth would cease. To investigate the trade-off between flower and cladode production, the numbers of flowers, fruits, and cladodes were monitored for 4 years on 30 Opuntia engelmannii Salm-Dyek, plants on Tumamoc Hill, Tucson, Arizona. Plant size controlled the number of flowers initiated each spring. The proportion of flowers that developed (i.e., did not abort) was perhaps determined by December-February rainfall in the months before bloom, with more being developed in the wettest years. Models based on different ratios of initiated cladodes to initiated flowers demonstrated that continued high investment in flowers and fruits would eventually terminate reproduction altogether; therefore periods of high sexual reproduction should alternate with periods of high vegetative growth. In the first 3 years of this study, the ratio of new cladodes to initiated flowers was low, showing a high investment in sexual reproduction. As suggested by the model, the population recouped this investment in the fourth year, when the number of new cladodes was nearly 3 times the 1992-1994 mean, and the number of initiated flowers was only 73% of the 3-year mean.

Arizona↗