Environmental Assessment
Volume B-4.1
Mine
Flora
Ambatovy Project
182
January 2006
Residual Impacts to Plant Diversity
During construction and operations, there will be a reduction in plant diversity
within the mine LSA. Approximately 1,700 ha of native vegetation, including
1,326 ha of azonal and transitional vegetation (46% of these vegetation types),
and 371 ha of zonal forest (3% of this vegetation type) will be cleared as a result
of mine-related activities. Native plant communities within the mine site are
considered to have high levels of diversity. Over time and as reclamation
proceeds, diversity is expected to increase but not to the levels observed at
baseline. Thus, the magnitude of effects is considered to be moderate. The
effects will be restricted to the local mine area and will continue beyond the life
of the project. Based on these factors, changes to plant species diversity are
predicted to result in a moderate environmental consequence.
Prediction Confidence
Confidence in impact predictions is related to four main elements:
•
Adequacy of baseline data for understanding current conditions.
•
Understanding of project-related impacts on the ecosystem.
•
Knowledge of the effectiveness of mitigation.
•
Probability of chance events.
Many of the flora impact predictions are based on the spatial distribution of
vegetation types within the mine LSA. The baseline vegetation map was
developed from a combination of orthophoto interpretation and ground-truthing.
Not all areas in the LSA were ground-truthed; however, the orthophotos were
stratified on the basis of tones and textures representing different vegetation
types, and sampling was done within most of the stratified units. Consequently,
the vegetation type classification is considered to be relatively accurate and
therefore the prediction confidence for direct effects on vegetation (i.e., loss of
vegetation types) is high.
Mitigation to deal with the effects of vegetation removal is primarily focused on
the following:
•
Establishing azonal conservation areas (on-site and off-site).
•
Forest management planning.
•
Forest rehabilitation/land reclamation.
