Conservation Costs of Retention Forestry and Optimal Habitat Network Selection in Southwestern Germany

Promoting the maintenance of biodiversity in managed forests should take into account economic efficiency of conservation plans. Therefore, novel economic valuation schemes must be developed in order to support conservation programs and mitigate biodiversity loss. Here, we assess the economic implications of retention forestry practices and create a habitat network in a mixed-montane forest in Southwestern Germany. We applied a simulation-optimization approach for i) evaluation of retention forestry practices applied in the region, ii) creation of forest reserves with a minimum eligible area for biodiversity conservation and establishing a connecting corridor with minimum cost, and iii) allocation of deadwood islands inside the connecting corridor with minimum cost. The average opportunity cost arising from retention forestry practices amounted to 1795 EUR/ha by leaving a minimum deadwood volume of 35 m3/ha and 2.5-5 habitat trees/ha. The optimized plan for establishing a habitat network would reduce the net present value (NPV) of forest management between 3.7% and 4.2%, and the novel design for the allocation of deadwood islands would impose a marginal reduction (<1%) to the NPV. We conclude that the creation of a habitat network for biodiversity conservation can be realized with the minimum trade-off to forest management profitability.