River Ecology and Restoration - River Dynamics and Integrated River Management - page 627

(a) (b)
(c) (d)
Fig. 10.2 (a) Forest matrix in the suburbs of Beijing, China; (b) A township patch and a surrounding stream corridor in
Wasserburg, Germany; (c) Stream corridor (the Leinbach River in Germany) and riparian forest matrix; and (d) Mosaic
consisting of forest, lake, island, and hills (Banff, Canada). (See color figure at the end of this topic)
terms can still be used to describe the ecological structure within watersheds. However, one could further
describe the watershed structure more meaningfully by also focusing on elements such as upper, middle,
and lower watershed zones, drainage divides, upper and lower hill slopes; terraces; floodplains; estuaries
and lagoons; and river mouths and deltas. Figure 10.3 displays examples of (a) the upper watershed (the
Yangtze River at the Shennongjia Mountain); (b) a mountain stream the Yellow River Basin); (c) an
alluvial river (the Blue Nile at the confluence with the White Nile River); and (d) an estuary (the Venice
Lagoon at the Po River mouth).
The river corridor is a spatial element (a corridor) at the watershed and landscape scales. Common
matrices in stream corridors include riparian forest or shrub cover or alternatively herbaceous vegetation.
Examples of patches at the stream corridor scale are wetlands, forest, shrub land, grassland patches,
oxbow lakes, residential or commercial development, islands in the channel, and passive recreation areas
such as picnic grounds. Figure 10.4 shows a cross section of a river corridor. The river corridor can be
subdivided by structural features and plant communities. Riparian areas have one or both of the following
characteristics: (1) vegetative species clearly different from nearby areas; and (2) species similar to adjacent
areas but exhibiting more vigorous or robust growth forms. Riparian areas are usually transitional between
wetland and upland
10.1.2 Biological Communities
The biological community of a river ecosystem is determined by the characteristics of both terrestrial and
aquatic ecosystems. The terrestrial ecosystem depends mainly on the plant community and the aquatic