18 The Seascape as an Indicator of Environmental Interest and Quality . . .
281
Table 18.3 Species or groups
of species which are rare or
limited to a particular
bathymetric section
Macrophyta
Lithophyllum lichenoide
Magniolophytes
Cnidaria
Corallium rubrum
Mollusc
Patella ferruginea
Fish
Sciaena umbra
Labrus bimaculatus
Shoal
Particular seabed
Coralligenous habitat
Maërl
to a particular bathymetric section, the Biological Description of a sector is therefore
directly correlated to their presence along a radial (Table 18.3). Other species or
groups of species have a large bathymetric distribution, the Biological Description
of the sector is directly proportional to the colonized surface and therefore to the
number of times they are listed across the entire radial which is divided into portions
of 50 m (Table 18.4).
For those species that are rare or strictly limited to a bathymetric section, the
diver notes the presence (or absence) of species or groups of species across the entire
radial. A value (v) of 0 or 2 which corresponds to the absence 0 or the presence (2)
across the entire radial is attributed. On the other hand, for the species or groups
of species which have a large bathymetric distribution, their presence or absence is
noted for each portion of 50 m, a value of 0, 1, or 2 is attributed by comparing the
frequency of their presence ( of presence for the portions i of 50 m/ the number
i of the portion of 50 m) with the expected frequency (Table 18.4). This method is
applied to all the species or groups of species for the indexes (R and S) in which they
occur.
The remarkable species: the R index. The remarkable species considered for the
biological description are, on one hand, those that benefit from local legal protection
regionally or in the administrative departments, nationally by means of decrees or
laws or internationally by means of conventions (Berne, Bonn, Barcelona); and on
the other hand, species which are not protected but considered to be regressing or
species considered to be vulnerable (Bellan-Santini et al. 1994; Harmelin 1991;
Lejeusne et al. 2010; Malak et al. 2011) (Table 18.5). Eleven species or groups of
species were considered.
For each radial, the value (v) attributed to each species or group of species is the
same as that described above. These values are integrated into the following equation
to calculate the R index for remarkable species:
R = vCystoseira sp + vL. byssoides + vMagnioliophytes + vCorallium rubrum
+ vCladocora sp. + vPatella ferruginea + vPinna sp. + nPalinurus elephas
+ vEpinephelus marginatus + vSciaena umbra + vLabrus bimaculatus/22
281
Table 18.3 Species or groups
of species which are rare or
limited to a particular
bathymetric section
Macrophyta
Lithophyllum lichenoide
Magniolophytes
Cnidaria
Corallium rubrum
Mollusc
Patella ferruginea
Fish
Sciaena umbra
Labrus bimaculatus
Shoal
Particular seabed
Coralligenous habitat
Maërl
to a particular bathymetric section, the Biological Description of a sector is therefore
directly correlated to their presence along a radial (Table 18.3). Other species or
groups of species have a large bathymetric distribution, the Biological Description
of the sector is directly proportional to the colonized surface and therefore to the
number of times they are listed across the entire radial which is divided into portions
of 50 m (Table 18.4).
For those species that are rare or strictly limited to a bathymetric section, the
diver notes the presence (or absence) of species or groups of species across the entire
radial. A value (v) of 0 or 2 which corresponds to the absence 0 or the presence (2)
across the entire radial is attributed. On the other hand, for the species or groups
of species which have a large bathymetric distribution, their presence or absence is
noted for each portion of 50 m, a value of 0, 1, or 2 is attributed by comparing the
frequency of their presence ( of presence for the portions i of 50 m/ the number
i of the portion of 50 m) with the expected frequency (Table 18.4). This method is
applied to all the species or groups of species for the indexes (R and S) in which they
occur.
The remarkable species: the R index. The remarkable species considered for the
biological description are, on one hand, those that benefit from local legal protection
regionally or in the administrative departments, nationally by means of decrees or
laws or internationally by means of conventions (Berne, Bonn, Barcelona); and on
the other hand, species which are not protected but considered to be regressing or
species considered to be vulnerable (Bellan-Santini et al. 1994; Harmelin 1991;
Lejeusne et al. 2010; Malak et al. 2011) (Table 18.5). Eleven species or groups of
species were considered.
For each radial, the value (v) attributed to each species or group of species is the
same as that described above. These values are integrated into the following equation
to calculate the R index for remarkable species:
R = vCystoseira sp + vL. byssoides + vMagnioliophytes + vCorallium rubrum
+ vCladocora sp. + vPatella ferruginea + vPinna sp. + nPalinurus elephas
+ vEpinephelus marginatus + vSciaena umbra + vLabrus bimaculatus/22