Contextualizing vulnerability of ecological systems to landscape alteration

Abstract

ContextA variety of processes, such as urbanization and development projects, can degrade connectivity in habitat systems, presenting significant threats to species persistence. Effective mitigation of such threats depends in part on knowledge about where and when landscape changes may occur as well as how species may respond to changes in the landscape.ObjectivesA spatial decision support framework for informing planning efforts involving alterations to the landscape that may impact prospects for species’ inter-habitat connectivity is proposed.MethodsAs a variety of movement objectives are thought to influence species’ perception of habitat connectivity, efficient paths supporting movement among habitats in a planning period are identified by way of a multiobjective least-cost path model. This set of paths represent the best options for inter-habitat connectivity in a particular planning period. Provided this representation of inter-habitat connectivity, the worst-case scenario of landscape alteration on inter-habitat connectivity is then identified. This multi-level optimization process is repeated over a set of planning periods until inter-habitat connectivity has been completely eliminated.ResultsThe results indicate that representing habitat connectivity with a limited set of paths reflecting a single objective for species movement could result in an overestimate of a habitat system’s resilience to landscape change over time. Representations of connectivity involving a more diverse set of paths reflecting tradeoffs among a set of objectives offer more robust representation of complex biological movements.ConclusionsThe application results indicate that landscape alterations occurring more proximate to habitat patches have the highest negative impact to connectivity. In addition, whereas alterations to the landscape may have no or little impact on inter-habitat connectivity in one planning period, when coupled with future alterations they can result in significant barriers to connectivity.