Environmental Engineering Reference
In-Depth Information
Dominance index
D
A measure of the degree of dominance by one or a few patch types in
a landscape:
H
max
þ
P
m
D
p
i
ln
p
i
where
H
max
is the maximum diversity when all patch types are present in equal
proportions,
m
is the total number of patch types, and
p
i
is the proportion of
the landscape area occupied by patch type
i
. Small values of
D
tend to
indicate landscapes with numerous land use types of similar proportions.
¼
i¼
1
Largest patch index
LPI
The ratio of the area of the largest patch to the total area of the landscape (unit:
percentage).
Mean patch size
MPS
The average area of all patches in the landscape (unit: ha).
Patch size standard deviation
PSSD
The standard deviation of patch size in the entire landscape (unit: ha).
Patch size coefficient
of variation
PSCV
The standard deviation of patch size divided by mean patch size for the entire
landscape (unit: percentage).
Landscape shape index
LSI
A modified perimeter/area ratio of the form:
LSI ¼
0
:
25
E
p
where E is the total length of patch edges and A is the total area of the landscape
(unitless).
Mean patch shape index
MSI
A patch-level shape index averaged over all patches in the landscape:
"
#
P
1
P
m
n
0
:
25
P
ij
a
ij
p
i
¼
j
¼
1
MSI
¼
N
where P
ij
and a
ij
are the perimeter and area of patch ij, respectively, and N is the
total number of patches in the landscape (unitless).
Area-weighted mean patch
shape index
AWMSI
Mean patch shape index weighted by relative patch size:
"
!
a
ij
#
A
¼
P
1
P
0
:
25
P
ij
a
ij
m
n
AWMSI
p
i
¼
j
¼
1
where P
ij
and a
ij
are the perimeter and area of patch ij, respectively, A is the total
area of the landscape, m is the number of patch types, and n is the total
number of patches of type i (unitless).
