Viable reserve networks and conservation incentives

Conservation in densely-settled biodiversity hotspots areas often requires setting up reserve networks that maintain sufficient contiguous habitat to support viable species populations. Because it is difficult to secure landholder compliance with an tightly constrained reserve network design, attention has shifted to voluntary incentive mechanisms, such as purchase of conservation easements by reverse auction or through a fixed-price offer. These mechanisms carry potential advantages of transparency, simplicity, and low cost. But uncoordinated individual response to these incentives has been assumed to be incompatible with conservation goals of viability (which depends on contiguous habitat) and biodiversity representation. Such incentives were modeled for southern Bahia in the Brazilian Atlantic Forest, one of the biologically richest and most threatened global biodiversity hotspots. Here, forest cover is spatially autocorrelated and associated with depressed land values, a situation that may be characteristic of longsettled areas with forests fragmented by agriculture. It was found that in this situation, a voluntary incentive system can yield a reserve network characterised by large, viable patches of contiguous forest, and representation of subregions with distinct vegetation types and biotic assemblages – without explicit planning for those outcomes.