214
C. Hily and M. Bernard
Table 13.1 IBFI: each value of the index is associated with a description at the landscape scale.
(Modified from Bernard 2012)
IBFI Values
IBFI = 0
IBFI = 1
IBFI = 2
% “Brown/red”
MBca
Between 96 and 100 % Between 76 and 95 %
Between 56 and
75 %
% “White/green”
MBca (i.e. GMC)
Between 0 and 4 %
Between 5 and 24 %
Between 25 and
44 %
Overall description
No visible impact.
Uniform coverage of
brown/red algae on
MB upper surfaces
across the boulder
field. Exceptional
observation of few
patches with a white
color or a green
algae cover
Dominance of
brown/red algae
coverage on MB
upper surfaces. Few
sparse patches of
white color or green
algae coverage on
MB upper surfaces
Brown/red color is
more two times
that of green white
color
No to rare white/green
MB, almost
exclusive presence
of brown/red MB
Strong dominance of
brown/red MB and
low representation
of white/green MB
High numbers of
brown/red MB
and white/green
boulders well
represented
IBFI Values
IBFI = 3
IBFI = 4
IBFI = 5
% “Brown/red”
MBca
Between 36 and 55 %
Between 16 and 35 %
Between 0 and 15 %
% “White/green”
MBca (i.e. GMC)
Between 45 and 64 %
Between 65 and 84 %
Between 85 and
100 %
Overall description
No dominance
between brown/red
color and
white/green color
Dominance of
white/green algae
coverage on MB
upper surfaces. Few
sparse patches of
brown/red color
Almost no brown/red
color at the
boulder field
scale. It is
dominated by
white/green color
Alternance of
undisturbed zones of
boulders (brown/red
MB) and disturbed
zones of boulders
(white/green MB)
Strong dominance of
white/green MB and
low representation
of brown/red MB.
Common
characteristics
beween the two
categories of MB
upper surfaces
No to rare brown/red
MB, almost
exclusive presence
of white/green
MB. Distinction
between
brown/red MB
and white/green
MB becomes
ambiguous
4. Estimation of the index value: on the field, two options can be developed.
(1) A rough but easy estimation of the green cover can be obtained from a
fixed point of view (localized by GPS) for a simple monitoring. Photographs
must be taken from this fixed position for further diachronic analysis. (2) A
better estimation can be obtained by applying a more accurate protocol based
on quadrats. Five 5*5 meters quadrats are placed randomly within the boulder
field. In each quadrat materialized by a rope, the total number of MB is
C. Hily and M. Bernard
Table 13.1 IBFI: each value of the index is associated with a description at the landscape scale.
(Modified from Bernard 2012)
IBFI Values
IBFI = 0
IBFI = 1
IBFI = 2
% “Brown/red”
MBca
Between 96 and 100 % Between 76 and 95 %
Between 56 and
75 %
% “White/green”
MBca (i.e. GMC)
Between 0 and 4 %
Between 5 and 24 %
Between 25 and
44 %
Overall description
No visible impact.
Uniform coverage of
brown/red algae on
MB upper surfaces
across the boulder
field. Exceptional
observation of few
patches with a white
color or a green
algae cover
Dominance of
brown/red algae
coverage on MB
upper surfaces. Few
sparse patches of
white color or green
algae coverage on
MB upper surfaces
Brown/red color is
more two times
that of green white
color
No to rare white/green
MB, almost
exclusive presence
of brown/red MB
Strong dominance of
brown/red MB and
low representation
of white/green MB
High numbers of
brown/red MB
and white/green
boulders well
represented
IBFI Values
IBFI = 3
IBFI = 4
IBFI = 5
% “Brown/red”
MBca
Between 36 and 55 %
Between 16 and 35 %
Between 0 and 15 %
% “White/green”
MBca (i.e. GMC)
Between 45 and 64 %
Between 65 and 84 %
Between 85 and
100 %
Overall description
No dominance
between brown/red
color and
white/green color
Dominance of
white/green algae
coverage on MB
upper surfaces. Few
sparse patches of
brown/red color
Almost no brown/red
color at the
boulder field
scale. It is
dominated by
white/green color
Alternance of
undisturbed zones of
boulders (brown/red
MB) and disturbed
zones of boulders
(white/green MB)
Strong dominance of
white/green MB and
low representation
of brown/red MB.
Common
characteristics
beween the two
categories of MB
upper surfaces
No to rare brown/red
MB, almost
exclusive presence
of white/green
MB. Distinction
between
brown/red MB
and white/green
MB becomes
ambiguous
4. Estimation of the index value: on the field, two options can be developed.
(1) A rough but easy estimation of the green cover can be obtained from a
fixed point of view (localized by GPS) for a simple monitoring. Photographs
must be taken from this fixed position for further diachronic analysis. (2) A
better estimation can be obtained by applying a more accurate protocol based
on quadrats. Five 5*5 meters quadrats are placed randomly within the boulder
field. In each quadrat materialized by a rope, the total number of MB is