Environmental Assessment
Volume E-4.1
Tailings Facility
Flora
Ambatovy Project
157
January 2006
4.1.5.2 Assessment Criteria
Residual impacts were determined based on a classification system that
incorporates direction, magnitude, geographic extent, duration, reversibility and
frequency of the impact as described in Volume A (Section 7.4). Determination
of the overall environmental consequence uses magnitude, geographic extent,
and duration. The assessment criteria used for plant communities are presented
in Table 4.1-1.
Table 4.1-1 Impact Description Criteria for Plant Communities
Direction
Magnitude
Geographic
Extent
Duration
Reversibility
Frequency
neutral
: no
change
(a)
in plant
communities
negative:
a change
in plant
communities
negligible:
no
measurable effect on
plant communities
low:
<10% change in
plant communities
moderate:
10-20%
change in plant
communities
high:
>20% change in
plant communities
local: effect
restricted to the
LSA
regional: effect
extends beyond
the LSA
short term: <3
years
medium term:
3 to 30 years
long term:
>30 years
reversible or
irreversible
low:
occurs
once
medium:
occurs
intermittently
high:
occurs
continuously
(a)
change in structure or composition
4.1.5.3 Mitigation
Mitigations are planned to reduce the magnitude, geographic extent and duration
of impacts from the project on flora within the tailings facility LSA. The main
areas of mitigation include:
•
maximize avoidance of key plant communities through siting design;
•
progressive reclamation of disturbed areas;
•
adherence to a closure and reclamation plan;
•
establishment of a reclamation trials program; and
•
consultation with local planners and stakeholders as to end use.
4.1.5.4 Results
Direct Losses to Plant Communities Within the Tailings Facility Local
Study Area
Direct losses to disturbed plant communities resulting from construction and
operation of the tailings facility will amount to 1,130 ha (45% of the tailings
