Environmental Assessment
Volume B-4.4
Mine
Natural Habitats and Biodiversity
Ambatovy Project
282
January 2006
•
Combined marsh edge forest and marsh ecotypes comprise 5% of the
LSA; all of these ecotypes are extremely rare relative to zonal habitat.
•
Ephemeral pools, which are unique to the azonal forest, represent the
rarest ecotype in the mine LSA. In the 1997 Phelps Dodge (PDM)
study, patches of marsh edge forest and ephemeral pools were
anticipated to be highly vulnerable to impacts because of their small size
and patchy distribution.
•
Current land use areas are associated with low biodiversity potential.
The amount of edge associated with land use areas is also high.
Table 4.4-2 Fragmentation Results for Primary Vegetation Communities
(Ecotypes) and Land Use Areas in the Mine Local Study Area
Landscape Metric
Azonal
Habitat
Transitional
Forest
Zonal
Forest
Ephemeral
Pools
Marsh Edge
Forest
Marsh Other
(a)
total area (ha)
1,380
1,489
12,573
5
231
915
6,301
proportion of total area (%)
6.0
6.5
54.9
0.02
1.0
4.0
27.5
mean area of patch (ha)
460
372
349
0.2
14
229
37
number of patches
3
4
36
30
16
4
171
mean distance to nearest
neighbour (m)
607
343
96
182
336
233
120
coefficient of variation in
distance to nearest
neighbour (%)
123
99
105
124
176
89
124
total edge (km)
70
127
665
6
58
114
580
(a)
Includes pasture, rice paddies, eucalyptus woodlots, slash and burn areas, and villages.
Forested land classes included disturbed and non-disturbed natural treed habitats,
and eucalyptus woodlots. Non-forested classes included disturbed natural
habitats in early succession, and various agriculture land use patches. Wetlands,
rice paddies, and human settlements were excluded from this analysis.
Fragmentation analysis indicated that forested land classes covered 15,887 ha of
terrestrial habitat in the LSA, while the amount of non-forested area was
5,539 ha. Mean patch size of forested habitat was 241 ha, and patches were
highly dispersed on the landscape (Coefficient of variation in distance to nearest
neighbour [CVDNN] = 297%). Non-forested patches were numerous and
moderately dispersed throughout the landscape (number of patches = 205,
CVDNN = 153%) (see Volume J, Appendix 4.1 for further discussion regarding
CVDNN).
