On the multiple ecological roles of water in river networks

Abstract

Abstract. The distribution and movement of water can influence the state and dynamics of terrestrial and aquatic ecosystems through a diversity of mechanisms. These mechanisms can be organized into three general categories wherein water acts as (1) a resource or habitat for biota, (2) a vector for connectivity and exchange of energy, materials, and organisms, and (3) as an agent of geomorphic change and disturbance. These latter two roles are highlighted in current models, which emphasize hydrologic connectivity and geomorphic change as determinants of the spatial and temporal distributions of species and processes in river systems. Water availability, on the other hand, has received less attention as a driver of ecological pattern, despite the prevalence of intermittent streams, and strong potential for environmental change to alter the spatial extent of drying in many regions. Here we summarize long-term research from a Sonoran Desert watershed to illustrate how spatial patterns of ecosystem structure and functioning reflect shifts in the relative importance of different 'roles of water' across scales of drainage size. These roles are distributed and interact hierarchically in the landscape, and for the bulk of the drainage network it is the duration of water availability that represents the primary determinant of ecological processes. Only for the largest catchments, with the most permanent flow regimes, do flood-associated disturbances and hydrologic exchange emerge as important drivers of local dynamics. While desert basins represent an extreme case, the diversity of mechanisms by which the availability and flow of water influence ecosystem structure and functioning are general. Predicting how river ecosystems may respond to future environmental pressures will require clear understanding of how changes in the spatial extent and relative overlap of these different roles of water shape ecological patterns.

A Conceptual Model of Vegetation–hydrogeomorphology Interactions Within River Corridors

“…These zones reflect the well‐understood hydrological and fluvial processes introduced in the preceding section and described fully in numerous texts (e.g. Charlton, ; Hendriks, ; Uhlenbrook, ; Wohl, ; Kondolf and Piégay, ) and the ‘multiple ecological roles of water in river networks’ reviewed by Sponseller et al (). However, the zonal concept that is associated with vegetation–hydrogeomorphological interactions is new and central to the conceptual model.…”

Rivers of the Anthropocene

“…The geophysical-sociocultural shifts of the Anthropocene, new baselines and accelerated change, may require new modes of scholarship better suited to these new contexts. Rivers are of immense importance, geologically, biologically, historically, and culturally, and they are central to many of the environmental issues that concern society (see, e.g., Sponseller, Heffernan, and Fisher 2013). It is clear, however, that we are entering an era in which humans are accelerating and decelerating natural processes and altering, creating, and destroying ecosystems at "an astonishing pace" (Syvitski 2012, 12).…”

“…In the Tyne and other U.K. catchments, reorienting the EU Water Framework Directive goals of "good ecological status" toward maximized ecosystem service provision can potentially deliver greater societal benefit within multiple-use river landscapes (Stanford and Poole 1996;Everard 2011 What constitutes a healthy Anthropocene river? As numerous researchers (e.g., Vorosmarty et al 2010;Carpenter et al 2011;Sponseller et al 2013) have attested, the multiple roles that water plays in both minimally and intensively manipulated ecosystems raise numerous challenges for efforts to reverse degradation. Perhaps most problematic is the lack of truly integrative approaches linking "supporting, " "provisioning, " and "regulating" ecosystem services with "cultural" ecosystem services.…”

River, Culture and Tourism in Lok Baintan, South Kalimantan

“…The ecological function of river has been describes by numerous authors. The roles of river can be classified into three basic categories namely rivers as natural resources as habitat for biota, a media for connectivity, energy, materials, and organisms exchange, and an geomorphical agent for change and disturbance [6]. Rivers ecosystem contributes significantly in the high level of biodiversity in Kalimantan Island, especially aquatic biodiversity.…”