ENVIRONMENTAL AUDITING: A Vegetation-Based Method for Ecological Diagnosis of Riverine Wetlands

Abstract

/ The management of riverine wetlands, recognized as a major component of biodiversity in fluvial hydrosystems, is problematic. Preservation or restoration of such ecosystems requires a method to assess the major ecological processes operating in the wetlands, the sustainability of the aquatic stage, and the restoration potential of each riverine wetland. We propose a method of diagnosis based on aquatic macrophytes and helophytes. Plant communities are used because they are easy to survey and provide information about (1) the origin of a water supply (i.e., groundwater, seepage, or surface river water) and its nutrient content, (2) effects of flood disturbances, and (3) terrestrialization processes. The novelty of the method is that, in contrast to available typologies, it is based on the interference of gradients resulting from several processes, which makes it possible to predict wetland sustainability and restoration potential. These predictions result from knowledge of the processes involved in terrestrialization, i.e., the influence of flood disturbances, occurrence of groundwater supplies, trophic degree, and water permanency of the habitat during a yearly cycle. The method is demonstrated on five different river systems.

Aquatic macrophytes as biological indicators of environmental conditions of rivers in north-eastern Spain

“…On the other hand, recent research has shown that local environmental conditions may be a less important factor than species colonisation processes in the distribution of macrophyte species (Demars & Harper 2005). Despite their limitations, macrophytes are undoub-tedly useful indicators of the environmental conditions of rivers, such as high trophic state (Kelly 1998, Thié-baut & Muller 1999, Amoros et al 2000, Kohler & Schneider 2003, Schneider & Melzer 2004. In fact, many authors have reported on macrophytes' role as valuable biological indicators of river water quality (Haslan 1987, Peñuelas & Sabater 1987, Romero & Onaindia 1995, Lazaridou et al 1997, Szymanowska et al 1999, Lehmann & Lachavanne 1999, Haslam 2000, Klumpp et al 2002, Demirezen & Askoy 2004.…”

Conservation status assessment of aquatic habitats within the Rhine floodplain using an index based on macrophytes

“…We show that at highest trophic level, there are high variations of specific diversity often related to a high level of disturbance (high connectivity, see Bornette et al 1998. Amoros et al (2000) showed that these two phenomenons, nutrient tolerance and disturbance, can interfere in some cases. An example is the oligotrophic species P. coloratus which is tolerant to physical disturbances, that is why this species could survive in connected sectors but under nutrient -low conditions.…”

Ecological evaluation of transitional and coastal waters: A marine benthic macrophytes-based model

“…Since they are important structural and functional components of the transitional and coastal waters, inhabiting sediment (roots of seagrasses) as well as water (seaweeds and leaves of seagrasses), they can potentially provide an integrated measure of ecological status. Several other models to predict ecological status of different aquatic ecosystems by using one (HOLMES et al, 1998;RITZ & TRUDGILL, 1999;AMOROS et al, 2000) or several types of bio-indicators (BRICKER et al 1999;GIBSON et al, 2000;LAFONT et al, 2001) have recently been developed. The main advantages of these models are: (1) Anthropogenic stress is evaluated from the community response (CROWE et al, 2000) and (2) The evaluation does not include antagonistic response parameters like nutrient concentrations (driving force) and phytoplankton or seaweed biomass (impact) in the same matrix.…”