The Formation of Channel and Floodplain Habitats Essay

The Formation of Channel and Floodplain Habitats - Essay Example The abundance of LW in stream channels is an indication of the intimate association of river ecosystems with the surrounding terrestrial environment (Naiman and Bilby 1998, Naiman and Dà ©camps 1997). Understanding this relationship is crucial in river basin management. Large wood abundance in the watershed depends on channel size, channel type, and the surrounding riparian forest. LW is more abundant in small channels on a per unit area basis because LW is easily transported in larger channels; it follows that whilst abundance in large channels is lower, the average LW sizes are bigger (Bilby and Ward 1989). LW is also more abundant where the stream channel is unconstrained and has fine substrate compared to constrained channels with boulder substrate (Bilby and Wasserman 1989). Moreover, LW is more abundant in forests where conifers are dominant compared to forests where hardwoods are dominant because conifers are larger making them less transient (Harmon et al., 1986). The abundance of LW is also more pronounced where the forest is mature than in forest dominated by young stands of small hardwoods (Bilby and Ward 1991). Woodland river ecosystems in their natural and pristine conditions are surrounded by riparian forest and have multiple channels. Over the years, the anthropogenic disturbance has greatly reduced riparian forest cover, the topography graded for agricultural purposes, and rivers were constrained by levees into a single channel (Caroll & Robinson, 2007; Florsheim & Mount, 2002). Other than forest denudation, this also has deleterious effects on the morphological development of stream and the stream biota.