Optimizing habitat management for amphibians: from simple models to complex decisions

Habitat loss, degradation and fragmentation remain leading causes of amphibian declines across the globe. To mitigate these impacts, conservation managers may protect core habitats and pursue habitat creation or enhancement actions, including construction of artificial wetlands, manipulation of wetland hydroperiods, removal of invasive species or restoration of aquatic and riparian vegetation. Yet management budgets are universally tight. When planning such actions, managers face the fundamental and complex problem of choosing where and when to invest limited resources to maximize the likelihood of species persistence. Here, we extend our previous research on this problem, and demonstrate the utility of coupling occupancy models with optimization algorithms to identify preferred habitat management schemes across multiple, disjunct habitat networks. Our real-world case study, completed in close collaboration with conservation managers, focussed on optimal habitat creation schemes for a threatened Australian frog in a rapidly urbanizing region. Our new technique identified clear priorities for investment in wetland construction both among and within seven disjunct habitat networks, solving a spatial prioritization problem that entailed millions of potential solutions and which was otherwise intractable. Such complex, multi-scale spatial prioritization problems are pervasive in amphibian conservation. Coupling occupancy models with spatial optimization algorithms represents a promising avenue to solve these problems and design habitat protection, creation and management schemes that maximize the chance of species persistence.