 |
| Titel |
Impact of gravel mining on benthic invertebrate communities in a highly dynamic gravel-bed river: an integrated methodology to link geomorphic disturbances and ecological status |
| VerfasserIn |
Maria Béjar, Chris Gibbins, Damià Vericat, Ramon J. Batalla, Cristina Buendia, Gemma Lobera |
| Konferenz |
EGU General Assembly 2014
|
| Medientyp |
Artikel
|
| Sprache |
Englisch
|
| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 16 (2014) |
| Datensatznummer |
250095008
|
| Publikation (Nr.) |
 EGU/EGU2014-10446.pdf |
|
|
|
|
|
| Zusammenfassung |
| Water and sediments are transported along river channels. Their supply, transport and
deposition control river morphology and sedimentary characteristics, which in turn
support habitat. Floods disturb river channels naturally although anthropogenic
impacts may also contribute. River channel disturbance is considered the main factor
affecting the organization of riverine communities and contributes to key ecological
processes.
In this paper we present an integrated methodology designed to analyze the impacts of
in-channel gravel mining on benthic invertebrate communities. The study is conducted in the
Upper River Cinca (Southern Pyrenees). A 11 km river reach is being monitored in order to
understand the effects of floods and gravel mining on channel morphodynamics and
invertebrate communities. The study reach is located in and upland gravel-bed system
historically and currently affected by periodical episodes of in-channel sediment mining.
This methodology has been developed in the background of the research project
MorphSed.
An integrated methodology of four components (Co) has been designed and is being
implemented: (Co1) acquisition of high resolution imagery to generate topographic models
before and after channel disturbances. Floods and in-channel gravel mining are considered
natural and anthropogenic disturbances, respectively. Topographic models are obtained by
means of combining automated digital photogrammetry (SfM) and optical bathymetric
models. Event-scale models are used to assess the spatial extent and magnitude of bed
disturbance. (Co2) Invertebrate sampling in 5 representative reaches along the study
site. Invertebrate surber samples are providing data to define assemblages and their
characteristics (composition, density, distribution, traits). These data is used to
assess the spatial extent of channel disturbance impacts on the taxonomic and trait
structure of communities. (Co3) Monitoring flow and sediment transport in the
upstream and downstream ends of the study site. These data is providing information
regarding to the magnitude of flood events (including hydraulics) and the sediment
budget in the study reach. Special emphasis is giving to the role of gravel mining in
increasing fine sediment availability and bed mobility. Finally, (Co4) a statistical
treatment of the data sets will be applied in order (i) to develop invertebrate-based
metrics to analyze the impact of bed disturbance and their recovery, and (ii) to
determine the most suitable physical metrics for detecting responses on benthic
invertebrates. These multi-event data sets will be a key goal for progress towards the
system-scale understanding of the interactions between river disturbance and ecological
responses, and provide the basis for an integrated methodology that can be used
to aid prediction, management and restoration of human stressed fluvial systems. |
|
|
|
|
|
|