A journey through space and time: impact of forest planning approaches on spatio-temporal habitat connectivity

Forest planning increasingly addresses biodiversity, yet planning often overlooks connectivity, which is a key aspect of conservation. To explore this issue, we compared the economic, ecological, and spatio-temporal connectivity impacts of different planning approaches aiming at landscape multifunctionality. We used deterministic multi-objective optimization to develop four scenarios that maximize the combined economic and ecological value in a boreal forest landscape in Norway. The scenarios varied according to two dimensions: (1) land unit specialization, comparing functional segregation and Triad functional zoning, and (2) spatial configuration, comparing a mosaic landscape with a spatially clustered configuration. Scenarios were evaluated over a 50-years planning horizon for their economic value, ecological value (using deadwood volume and habitat availability for three forest bird species), and spatio-temporal connectivity (using the Probability of Connectivity index). The Triad scenario performed better for deadwood volume (+11%) and habitat availability (+21%), with 10% economic losses compared to segregation. Triad maintained higher connectivity for the three-toed woodpecker, while for the long-tailed tit and the hazel grouse, it resulted in connectivity values similar to those under the segregation approach. Spatial clustering of conservation stands improved the economic value (5 to 8%) but at great costs for habitat availability (from -39 to -17%) and spatio-temporal connectivity (from -49 to -29%). Our results suggest that planners should prioritize increasing habitat availability over spatial configuration, at least in the short to medium term when overall habitat is scarce. In this context, connectivity metrics can support decision-making when planning for species conservation in a managed forest landscape.