Environmental Assessment
Volume C-4.4
Slurry Pipeline
Natural Habitats and Biodiversity
Ambatovy Project
157
January 2006
Direct impacts from the project are predicted to be local in geographic extent.
The buffer provided for the pipeline (1 km either side) should contain all project-
related impacts (habitat and fragmentation effects) associated with the expected
25 to 100 m zone of disturbance. Construction of the pipeline is expected to take
two years so disturbance will be medium in frequency. Habitat loss and
associated fragmentation effects from construction and operations are predicted
to be medium-term in duration, and reversible. The pipeline will be buried
immediately, and operation of the maintenance road for project-related activities
will cease at closure.
During operations and closure, reclamation is anticipated to reverse impacts to a
negligible magnitude. Based on adjacent vegetation, revegetation will likely
provide habitats with similar structure and composition as existing primary and
degraded forest, and provide suitable habitat for plants and animals (although the
small change in wetlands will likely be irreversible). The marginal amount of
disturbance to habitats and associated negligible fragmentation effects should
enable the ecosystem to return to an equilibrium state within the operation phase.
It is anticipated that ecosystem stability will increase further during closure.
Reclamation will occur periodically (medium frequency), with a medium-term
duration.
Taking all criteria into consideration, the environmental consequence of direct
impacts from the project on natural habitats and biodiversity is predicted to be
low during construction and operation, and negligible during closure
(Table 4.4-7).
Prediction Confidence
Confidence in residual impact predictions is related to the adequacy of baseline
data for understanding current conditions, understanding of project-related
impacts on the ecosystem, and knowledge of the effectiveness of mitigation.
Estimates of the metrics used to assess current biodiversity in the pipeline study
area (i.e., species richness, endemism and conservation status) were a function of
baseline sampling intensity and distribution, and the types of taxa sampled.
Given the nature of the sampling distribution and intensity (see Volume J;
Appendices 1.1, 2.1, 3.1), it is likely that not all species inhabiting the study area
were recorded. This is not surprising considering the amount of effort required to
collect a detailed inventory of tropical species, even from one area (Lawton et al.
1998). Consequently, the number of potential impacted species is uncertain.
Thus, there is a moderate degree of uncertainty as to whether the marginal
decrease in primary habitats will surpass potential threshold levels for species to
be able to absorb project-related changes and persist into the future.
