The Offset Design Process
46
BBOP Pilot Project Case Study – Ambatovy Project
It is important to note reforestation of the azonal forest area will create zonal type forest, with some azonal
influences arising from the use of backfill originating in the azonal areas (which has specific geochemistry and
broken ferricrete crust and pisolitic iron). Complete restoration to azonal habitat is deemed impossible due to
its strong links with the removed ground structure and geochemistry.
To improve the basic simulation discussed above, the Project will collect available rehabilitation data for
Madagascan lateritic soils and the eastern domain. This will enable the refinement of reforestation predictions.
Based on Madagascan forestry experience, it is estimated that at 30 years forests will begin to offer a habitat
that can be exploited by lemurs and other important taxa, for both food and shelter. The closure biodiversity
programme will include monitoring of priority taxa in these rehabilitated areas to define the rate of
recolonisation. Irrespective of improvements in the model, continuing care in integration of rehabilitation data
in the loss calculations will be necessary due to:
1. Limitations in the availability of specific information on Malagasy forests rehabilitation success rates;
2. The specificity of the Ambatovy mine site forests and overall associated uncertainties; and
3. The risk that lower success rates may occur despite improved confidence in predictions.
Consequently, the Project may decide to take a more precautionary approach and retain conservative habitat
hectares scores to ensure that
NO NET LOSS
is not undermined by an undersized offset design.
7.3.6 Step 6: Review potential offset locations and activities and assess the
biodiversity gains which could be achieved at each
Identifying offset options
Preliminary surveys of offset candidate sites were undertaken in 2005 (see Appendix 6, Survey for Off-site
Azonal Outcrops (in French)) with the objective of identifying potential in-kind type offsets. The surveys were
based on geological, substrate, altitude and forest structure similarities (see Figure 9, showing correlation
between the EVC (azonal, transitional and zonal), substrate and topography) and comprised:
A desk study using geological maps to identify ultramafic outcrops and satellite imagery for remaining
forest cover.
Aerial (plan) reconnaissance survey to confirm the presence of forest cover and rapid visual integrity
assessment; the survey had to be conducted by air, due to the absence of road infrastructure and general
remoteness of the areas. Two potential candidate sites (of 14 initially identified – see Figure 8) were
chosen based on forest integrity and surface area.
Aerial (helicopter) reconnaissance survey and walk over ground survey of potential candidate sites
(Vohimenakely and Ankerana). Vohimenakely, located northwest of Zahamena National Park appeared to
have azonal characteristics but was very small (<10 ha) and highly disturbed. Thus, this location has some
potential for off-site purposes, but it is not highly regarded because of its small size and relatively poor
condition. Ankerana, located northeast of Mantadia National Park is the best potential off-site azonal
vegetation area among those visited. It had the general appearance of Analamay, although the presence
of ferricrete could not be confirmed from the air. It appeared a reasonable size (>500 ha) and with no signs
of disturbance (see Photograph 1).
A ground-level vegetation survey at selected candidate site (Ankerana) to determine if it has similar habitat
and floristic (see Photograph 2) characteristics as at Ambatovy and Analamay. The preliminary comparison
of the Ankerana area with Ambatovy / Analamay is presented in Appendix 7. Ankerana had previously and
independently been identified by the Missouri Botanical Garden – Madagascar (a Project partner) as a
