Mining and conservation: implications for Madagascar's littoral forests

Abstract

A recent article in Conservation Letters by Virah-Sawmy (2009) presents new evidence with the potential to change conservation planning in Madagascar. However, it ends with unsubstantiated policy recommendations that, if followed, could accelerate clearance of the few remaining patches of littoral forest in south-eastern Madagascar, one of the most threatened ecosystems on the island. The principal threat to littoral forests in southeastern Madagascar is mining. One justification for the conversion of remaining littoral forests for mining has been that these forests have been heavily cleared since prehistoric times and will therefore be lost anyway in the near future (QIT Madagascar Minerals 2001). Using paleo-ecological data, Virah-Sawmy convincingly shows that this justification is not scientifically supported as the patchy distribution of littoral forest is best explained by soil moisture rather than the actions of past human activities. In fact, it is only in the past three decades that large-scale deforestation has occurred in some stands of littoral forest, and this has been associated with the mining venture (Ingram & Dawson 2006). In a surprising set of policy recommendations, Virah-Sawmy does not call for the cessation (or reassessment) of mining activity in the threatened littoral forest ecosystems, but contends that “Based on our analysis, we suggest that if the appropriate conditions and measures are put in place for restoration … the littoral forest may once again expand and regenerate after the degradation it suffered in the last few decades … .” These recommendations are highly problematic for two reasons. First, with about 6,000 ha (80% of the littoral forest in the region) subject to planned clearance over the next 50 years (Vincelette et al. 2003), it seems obvious to us that conservation policy must focus foremost on reducing the areal extent of habitat loss. Second, Virah-Sawmy did not investigate the appropriateness of offsetting or restoration activity, so her claim that littoral forests can be restored “if appropriate conditions and measures” are taken, is simply unsubstantiated. In fact, littoral forest plants grow more slowly in demineralized soils in comparison with normal soils and grow poorly away from standing forest fragments (Vincelette et al. 2007). Moreover, the size of the proposed conservation zone currently planned (three patches protected with a total size of 970 ha; Vincelette et al. 2003) is dwarfed by the amount of habitat about to be lost, so does not “compensate for residual, unavoidable harm to biodiversity” in Virah-Sawmy's own words. This level of reservation is inadequate for the persistence of littoral forest bird and mammal communities and for key ecological functions such as seed dispersal (e.g., Ramanamanjato & Ganzhorn 2001; Bollen et al. 2004; Watson et al. 2004, 2005, 2009). Although we believe that Virah-Sawmy has provided a valuable historical perspective on forest patchiness in southeastern Madagascar, mining is a serious imminent threat to endangered littoral forest ecosystems, and it is imperative that conservation policy recommendations do not unintentionally condone proposed habitat destruction by treating it as a fait accompli.