The Offset Design Process
42
BBOP Pilot Project Case Study – Ambatovy Project
been collected in 2009. The inclusion of fish components for stream habitats will also require further
analysis and consideration.
VULNERABILITY
: although this attribute was integrated in the April 2008 calculations (see Appendix 5), it is
excluded from the present iteration of the loss calculations. The taxa groups should be considered
together, not only at the species level, so that the same weight can be given to all taxa (lemurs, birds,
herpetofauna, etc). This would allow the Project to consider not only specific species, but also the
taxonomic groups that are important for monitoring purposes. In fact species
EXTIRPATION
can sometimes
be linked to group effects or intra-species interactions; therefore, it is best to consider taxa group
vulnerability rather than that of specific species. It is thus assumed that vulnerability considered as an
attribute makes more ecological sense than that considering specific species alone. However, the use of
vulnerability attributes requires further detailed analysis, to be conducted in 2009.
Calculating biodiversity loss at the impact site
The attributes presented above are for the mine and pipeline components.
As described in the previous sections, the pipeline’s impact on forest habitat is very limited since routing
avoided relic forest fragments present in the first 32 km (after which the area crossed is entirely exotic
secondary vegetation resulting from slash and burn activities). Only the first 2 km of the pipeline cross quasi
primary forest, and these losses were included in the mine loss calculations. The pipeline’s losses thus
correspond to the forest fragments (16.5 ha) that could not be avoided: the habitat hectares could be
calculated for this as the area impacted could be compared to the zonal forest
BENCHMARK ATTRIBUTES
. The
pipeline’s forest fragments are classed as Ecological Vegetation Class (EVC) 3: ‘heavily fragmented and
degraded primary forest’. Instead of using the ‘basal area’ attribute, ‘volume’ was considered since these
forests are heavily exploited by the local communities for fire wood. Volume can also be used in the future
socioeconomic compensation analyses. The pipeline’s aquatic components include the crossing of more than
400 streams with variable levels of ecological integrity and sensitivity. However, pipeline-related impacts to
the aquatic environment are considered temporary, which cannot be captured by the habitat hectare
methodology. The Project will therefore use methodological options for integrating temporary impacts in the
next iteration of the loss calculations.
The locations of the processing plant and tailing management facility have an EVC of 4 (essentially heavily
degraded, with no remaining integrity, based on ESIA data). The habitat hectares calculation for this fourth
category has not yet been undertaken for these areas. However the Project is committed to ‘
TRADING UP
’
these areas and will work with BBOP to define an appropriate methodology for doing so. The harbour has
been used as an industrial port for some time and little biodiversity of any significant conservation value is
found there now.
The mine area includes two Ecosystem Vegetation Classes (EVC): ‘quasi pristine primary forest’ and
‘disturbed primary forest’. The pipeline has only one EVC: ‘heavily fragmented and degraded primary forest’.
For each EVC the Project will have either a:
‘High impact’ corresponding to total forest clearance with or without grubbing (removal of stumps, roots,
and vegetable matter). A total area of 1,336 ha will fall in this impact category.
‘Medium impact’ corresponding to the environmental buffer around the mine footprint (100 m) and linear
features (pipeline / roads, with a 50 m buffer), which will be indirectly affected by forest clearance (impacts
are mainly through edge effects such as light, dust and unauthorised disturbances.
