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General abstract
Territories
face more and more the consequences on the environment
of the human activities (agriculture, forestry and
industry) and are forced to restore the damaged areas.
The involvement of the professional men and women to the
collaborative production of scientific results with
researchers forms the singularity and relevance of this
scientific area. It answers to necessary demand to
understand scientific and technical mechanisms of
ecosystems, and to develop adapted solutions. This
special issue illustrates the variety of actions of
research lead in this theme. It also focuses on the
specific case of abraded lands and the use of the
biological engineering to rehabilitate them.
Decision-making tools for accidental pollution
management of rivers: toward sustainable solutions
Isabelle Laffont-Schwob, Xavier Moreau, Véronique
Masotti, Carole Di Giorgio, Laetitia De Jong-Moreau,
Jacques Rabier, Michel De Méo, Caroline Martin-Chauvin,
Luc Sarrazin, Fabienne Rousset and Alain Thiéry - p.
9-16
Abstract
Industries regularly interface with natural environment.
The natural environment is often impacted when
accidental industrial pollution occurs. Classical
procedure makes use of physico-chemical analyses to
state the pollution of the environment. However,
diagnosis on the living is often neglected in this
inventory. The authors suggest an approach adapted to
rivers to identify the impacts on the living. This
approach may be a decisional tool for field operationals
and a first step towards rehabilitation or ecological
restoration of environment.
Small dam removal: a tool for landscape and ecological
river restoration? Focus on social issues – French case
studies – Sèvre nantaise, Thouet (west of France)
Régis Barraud, Olivier Constantin, Guillaume
Charruaud and Antoine Charrier - p. 17-30
Abstract
Small dam removal (most of them are watermills dams or
irrigation weirs) has become a new option in river
ecological restoration. From United-States to european
countries dam removal (and particularly small dam
removal) has emerged as a major environmental managment
issue. The European Water Framework Directive (EWFD)
encourages States and local authorities to reduce
ecological impact of these hydraulic works (fish-pass,
small dam removal). This new context leads to the
increase of conflicts of use and to indecisive public
policies. This article deals with this issue through the
analysis of two cases studies in western France (Sèvre
nantaise, Thouet).
How emerging trees can be used for a passive restoration
of the stream banks at Vallée-Aux-Berges (Normandy,
France)
Guillaume Forget and Ivan Bernez - p. 31-39
Abstract
Riparian
ecosystems are complex and sensitive. The restoration of
these ecotones can be done in particular by the
reforestation to prevent from the erosion. The aim of
this study hold on the ecological restoration of a
headwater stream in Normandy, France : we studied the
natural reforestation of the banks by a passive
restoration method. Our results show a rapid recruitment
of young shrubs and trees the first year and a
stabilization after one year. An increase of specie
richness and of the species distribution heterogeneity
is notice on all the area. Furthermore, downstream
meadows are more diversify than those upstream. This
study brings to light the ecological efficiency of
passive restoration and its potential for riparian
reforestation.
Herbaceous vegetation restoration of urban sandy areas –
Assessment of urban greenspaces management
Maxime Guérin, Caroline Gutleben and Hervé Daniel -
p. 41-53
Abstract
Some towns
have decided to stop chemical weed control of sandy
areas and to transform them into herbaceous plant
communities. There is a need for a global assessment of
management techniques and their consequences for plant
cover. A survey of such practices has been conducted in
13 towns. Vegetation has been recorded at 56 sites
within 9 towns. This field study aims to assess the
influence of various factors in vegetation restoration.
The survey showed that restoration measure may be
efficient ; the slowness of the installation of
spontaneous herbaceous vegetation may be a problem for
the managers of green spaces because it is sometimes
negatively perceived by the citizens. Therefore,
appropriate communication explaining objectives and
interests of these practices is essential to increase
their acceptance by the local population.
Experience feedback of mitigations mesures and
environmental accompaniing works about Port 2000
Christophe Aulert, Pascal Provost, Christophe
Bessineton and Christelle Dutilleul - p. 55-72
Abstract
In 2001,
different works to extend the harbour of Le Havre, Port
2000, have been initiated in the Seine estuary (France).This
extension is located near one of the most important
National Nature Reserve in France and concern one part
of the EC protected area for the birds “estuary and
wetlands of the Basse Seine”. The major consequence of
these important works where to distroy the main high
tide resting area for the limicols and other water
birds. They also contribute to increase
hydro-sedimentary impacts in the estuary in addition to
draggings and reclamations done during the last century.
To take in account these important environmental stakes,
mitigations mesures and environmental accompaniing works
have been initiated to reduce the impacts of “Port 2000”
project on habitats and species : the dredging of a
channel 2800 m long, creation of a high tide resting
zone for birds of 40 ha large, creation of an artificial
island for birds. After six years of monitoring, results
are showing what is running well and what mesures are
not completely eficient and need modifications.
What kind of surveys for follow-up and evaluation of
ecological restoration operation ? Example of the
Quiberon's « Côte Sauvage »
Sébastien Gallet, Frédéric Bioret and Armelle Hélou -
p. 73-81
Abstract
Among the
numerous operations of ecological restoration set up in
particular on over-frequented sites of the French
Atlantic coast, only few of them are the object of
scientific (follow-up) monitoring ?, which are
necessary for the evaluation of the success of used
techniques. These surveys also allow to identify the
blocking or the drift in the dynamics of the concerned
systems. One of the reasons of this lack of such surveys
is the absence of standardized, simple methodology
allowing a global evaluation of such operations. Within
the framework of a collaboration between scientists and
site managers, we established a method of evaluation
based on a simplified mapping and criteria allowing to
monitor the dynamic of the system, without requiring
deepened knowledge in botany or in ecology. The
objective is to define a methodology which can be
operated at regular intervals, without prohibitive cost,
within the framework of recent operations but also for a
posteriori evaluation of older ones.
Measurements of suspended load in the Durance river over
150 years (1857-2007): links with the operations of
ecological restoration at the scale of the catchment and
the river
Alain Poirel - p. 85-98
Abstract
The aim of
this paper is to make a review of suspended sediment
load in the Durance river for 150 years, trying to
relate evolutions to changes in the basin and in
hydroclimatology. This work illustrates the difficulty
of isolating the factors of each others because the
feedback loops between processes are numerous. Essential
for erosion, forest cover, for example, has been
significantly increased to approximately 40 % of the
basin today. Before 1948, this increase is mainly due to
reforestation of eroded mountains (260 000 ha). After
that date, the processes of natural recolonization of
degraded land is fundamental. On marly small
experimental basins near Digne, in the Bleone sub-basin,
we now measure specific annual production of sediments
220 times less important in a catchment with a
vegetation coverage of 87 % that a catchment with a
vegetation coverage of 32 %. To analyze the data during
more than a century, it is also necessary to understand
the "relationship to the object of study" that
scientists from different periods have because their
motivations directly affect the datas and papers that
they leave to us. This should make us think on those we
will leave to future generations.
Bioengineering techniques for erosion control in rivers:
age old techniques in constant progress
Pierre-André Frossard and André Évette - p.
99-109
Abstract
Soil
bioengineering techniques against erosion are very old
techniques. The principle of the techniques is to use
biological, physiological and physical abilities of
plants to get solutions against soil erosion. Soil
bioengineering techniques can be applied to riverbanks
but also for other kinds of slopes, for ecological
restoration or to prevent from natural hazards
(avalanche...). Soil bioengineering applied to
riverbanks is ruled by a specific regulation. Mechanical
resistance of these works is hard to define accurately,
and increase with time. New researches are currently
done about ecological characterization of species
already used and other quite news. At least, we can
quote the recent creation of the French association for
soil bioengineering for erosion control (AGEBIO) that
aims to federate parties involved.
Evaluating species response to erosive perturbations:
implication for the ecological restoration of eroded
lands
Mélanie Burylo and Freddy Rey - p. 111-120
Abstract
The aim of
this paper is to illustrate how current investigations
on species response to erosive perturbations can be of
major interest for the ecological restoration of eroded
marly lands in the French Southern Alps. Indeed,
restoration ecology and ecological engineering are close
fields, both stemming from applied ecology, but
belonging to two different circles, respectively the
researcher’s and the practitioner’s world. These two
disciplines are complementary and present strong
interactions. The aim of our investigations is to
determine, explain and predict species resistance to
uprooting and burial by marly sediment caused by
concentrated runoff and shallow mass movements. The use
of plant traits to relate species performance to their
morphological characteristics offers the possibility to
generalize the results and is therefore highly relevant.
The results of our study can be integrated in different
ways into ecological rehabilitation or restoration
actions. They can be used to evaluate the success of
restoration projects or the vulnerability of eroded
lands, and to optimize management strategies.
TLALOC: a spatio-temporal model of vegetation dynamics
related to erosive and sedimentologic dynamics in marly
gullies
Philippe Delcros, Maëlle Lepoutre, Mélanie Burylo and
Freddy Rey - p. 121-134
Abstract
The marly
gullies of the French Southern Alps are frequently
subjected to torrential floods. The latter are
responsible for erosive hazards leading to damages
downstream (increase of flood risk, silting of
hydroelectric dams). For erosion control, using
bioengineering allows creating stabilization of the
gully floors, revegetating them and favouring vegetation
dynamics. In this context, we developed a spatio-temporal
and stochastic model simulating natural vegetation
dynamics on the stabilized soil (installation, growth,
competition, mortality) at the plant scale, as well as
flood events (depending on frequency, date and
intensity) and their impact on vegetation. The final
objective of this model is to estimate the successful
probability of a bioengineering work in sediment
trapping.
Erosion
and landscape in Mediterranean mountains – Learning of a
comparison from Southern France and Spanish Catalonia
study cases and literature
Marianne Cohen, Francesc Aspero, Véronique Fourault,
Alia Gana, Catherine Mering, Luis Outeiro, Milena
Palibrk, Ana Poletto, Raymond Raymond and Xavier Ubeda -
p. 135-156
Abstract
A
comparative study France-Spain of the relationships
between erosion, landscape and sustainable development
is relied on measurements and regionalization of erosion
and inquiries of local stakeholders. In Catalonia
(wooded matrix), the paths produce sediments, in
Southern Alps (mosaic landscape pattern), it is the case
of the badlands. These measurements are confirmed by the
first results of a generalization study, with a special
methodology. Local stakeholders do not take enough in
consideration erosion problem ; they are more concerned
by fire hazard (Catalonia) and shrub encroachment
(French Alps).
Do
the sustainable development territorial strategies help
for designing ecological engineering projects? Some
cases study in the French South Alps
Alain Bédécarrats - p. 157-165
Abstract
Ecological
engineering projects affect spaces belonging to
territories on which environmental and social questions
are addressed. Those questions have to be taken in
account in the design of projects at the local scale.
Territorial charters or management plans are documents
displaying territorial sustainable development
strategies. In this work one examines the possibility to
use those documents in order to identify the territorial
scale specifications with which the ecosystems and
landscape design has to comply. Documents describing
five territorial strategies
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Contact :
ingenieries@cemagref.fr
