Understanding natural patterns and processes in river corridors as the basis for effective river restoration

Abstract

Running water ecology is a young science, the conceptual foundations of which were derived largely from research conducted in Europe and North America. However, virtually all European river corridors were substantially regulated well before the science of river ecology developed. While regulation of North American river systems occurred later than in European systems, river ecology also developed later. Therefore, there is a general impression of rivers as being much less heterogeneous and much more stable than they actually are in the natural state. The thesis of this paper is that established research and management concepts may fail to fully recognize the crucial roles of habitat heterogeneity and fluvial dynamics owing to a lack of fundamental knowledge of the structural and functional features of morphologically intact river corridors. Until quite recently, most concepts in river ecology were based on the implicit assumption that rivers are stable, single-thread channels isolated from adjacent floodplains. Unfortunately, many rivers are in just such a state, but it should be recognized that this is not the natural condition. This incomplete understanding constrains scientific advances in river ecology and renders management and restoration initiatives less effective. Examples are given of the high level of spatio-temporal heterogeneity that may be attained in rivers where natural processes still operate on a large scale. The objective of this paper is to promulgate a broader and more integrative understanding of natural processes in river corridors as a necessary prelude to effective river conservation and management.

Nutrient dynamics, transfer and retention along the aquatic continuum from land to ocean: towards integration of ecological and biogeochemical models

“…2) fail to describe how nutrients and sediments are delivered to streams and rivers through weathering, leaching from soils, transport through groundwater and riparian areas and denitrification therein, and erosion. Except for the telescoping model, the concepts do not include the vertical dimension, i.e., the continuum of upland soil, groundwater, riparian zone, and hyporheic zone (Ward et al, 2001), particularly with respect to the flows of water and nutrients therein. Biogeochemistry is an integrative discipline.…”

Site-Occupancy Monitoring of an Ecosystem Indicator: Linking Characteristics of Riparian Vegetation to Beaver Occurrence

“…Restoration and management of regulated rivers can be difficult because of competing demands for water and differences in dynamics between systems (Schmidt et al 1998). However, one commonality to all restoration and management projects is the need to accurately monitor key species associated with riverine processes (Ward et al 2001).…”

Grays River Watershed and Biological Assessment Final Report 2006.

“…The loss of floodplain connectivity and side-channel areas within a river system can significantly reduce sediment storage capacity (Ward et al 1999(Ward et al , 2001. Instream LWD, especially large logjams, can also be very effective in storing sediment within stream channels .…”