172
A. Cheminée et al.
11.4 Discussion: Applying the Seascape Approach with Regard
to Management of the Infralittoral
Over the whole territory of the Calanques National Park, the extent of the nurseries
is small (less than 8 % of the total coastline). In addition, most of these nurseries
are situated outside the core area, within the AMA, where the anthropic pressures
are high (bays of Marseille and La Ciotat) and where the level of protection is by
definition lower (cf. 3.2). These data thus confirm those of Cheminée et al. (2011):
the white seabream nurseries within the core area of the Calanques National Park
would appear to be insufficient in themselves to ensure the renewal of the local
adult populations which probably depend on the migration of recruits from the more
abundant nurseries situated within the adjacent maritime area (AMA).
The management zoning in our study does not a priori take into account all the
essential habitats and their connectivity (seascape approach). There are however
examples of the management of natural environments that adopt this approach at
seascape level and notably the notion of connectivity: the concept of ‘ecological
solidarity’ encompasses these principles and is the focus of current discussion within
the French national parks authority (Parcs Nationaux de France) (INEA et al. 2009;
Thompson et al. 2009; Gabrié et al. 2007). The Ramsar convention (1971) and
the recommendations of the various subsequent members’ conferences have also
encouraged their members to take into account the functionality of the habitats and
processes of connectivity, at landscape scale, for the selection of their ‘wetlands
of international importance’ (Direction de l’Agriculture de Mayotte et al. 2002;
Cheminée 2002).
We propose here a conceptual schema (Fig. 11.6), illustrated by our case study
and applicable in a general way to the management of any coastal site in order to
favour a ‘seascape’ approach.
The aim is firstly to manage the habitats of juveniles (Fig. 11.6, point a). To this
end, once the characteristics of the habitats of juveniles (nurseries) are known (b)
they are mapped (c) for the purposes of localisation and quantification. In a zone
under statutory protection (core area of the park in our example; d), the aim is to
conserve the nursery value of the habitat: this requires in particular (e) the strict
maintenance of the characteristics of the micro-habitat; in the case of the white
seabream (Diplodus), it has been shown (Cheminée et al. 2011) that it is necessary
to respect the heterogeneous character of shallow gently sloping bottoms if they are
to perform their nursery function (notion of ‘heterogeneity’ and ‘complexity’, for
further details see Box 1). In our case study, the nurseries situated within the core
area benefit from a high level of protection: the special core area regulations entails
a principle of a ban on development works, construction and installations, concerning in particular the DPM (Domaine Public Maritime—public maritime domain),
without special permission, which gives the public authority the means to protect
these habitats from direct destruction. In certain cases, if the statutory protection is
insufficient (f), the competent public authority can propose (g) additional statutory
measures: for example, to specifically list the habitats and their characteristics that
A. Cheminée et al.
11.4 Discussion: Applying the Seascape Approach with Regard
to Management of the Infralittoral
Over the whole territory of the Calanques National Park, the extent of the nurseries
is small (less than 8 % of the total coastline). In addition, most of these nurseries
are situated outside the core area, within the AMA, where the anthropic pressures
are high (bays of Marseille and La Ciotat) and where the level of protection is by
definition lower (cf. 3.2). These data thus confirm those of Cheminée et al. (2011):
the white seabream nurseries within the core area of the Calanques National Park
would appear to be insufficient in themselves to ensure the renewal of the local
adult populations which probably depend on the migration of recruits from the more
abundant nurseries situated within the adjacent maritime area (AMA).
The management zoning in our study does not a priori take into account all the
essential habitats and their connectivity (seascape approach). There are however
examples of the management of natural environments that adopt this approach at
seascape level and notably the notion of connectivity: the concept of ‘ecological
solidarity’ encompasses these principles and is the focus of current discussion within
the French national parks authority (Parcs Nationaux de France) (INEA et al. 2009;
Thompson et al. 2009; Gabrié et al. 2007). The Ramsar convention (1971) and
the recommendations of the various subsequent members’ conferences have also
encouraged their members to take into account the functionality of the habitats and
processes of connectivity, at landscape scale, for the selection of their ‘wetlands
of international importance’ (Direction de l’Agriculture de Mayotte et al. 2002;
Cheminée 2002).
We propose here a conceptual schema (Fig. 11.6), illustrated by our case study
and applicable in a general way to the management of any coastal site in order to
favour a ‘seascape’ approach.
The aim is firstly to manage the habitats of juveniles (Fig. 11.6, point a). To this
end, once the characteristics of the habitats of juveniles (nurseries) are known (b)
they are mapped (c) for the purposes of localisation and quantification. In a zone
under statutory protection (core area of the park in our example; d), the aim is to
conserve the nursery value of the habitat: this requires in particular (e) the strict
maintenance of the characteristics of the micro-habitat; in the case of the white
seabream (Diplodus), it has been shown (Cheminée et al. 2011) that it is necessary
to respect the heterogeneous character of shallow gently sloping bottoms if they are
to perform their nursery function (notion of ‘heterogeneity’ and ‘complexity’, for
further details see Box 1). In our case study, the nurseries situated within the core
area benefit from a high level of protection: the special core area regulations entails
a principle of a ban on development works, construction and installations, concerning in particular the DPM (Domaine Public Maritime—public maritime domain),
without special permission, which gives the public authority the means to protect
these habitats from direct destruction. In certain cases, if the statutory protection is
insufficient (f), the competent public authority can propose (g) additional statutory
measures: for example, to specifically list the habitats and their characteristics that