Natural resource managers frequently face difficult decisions that attempt to promote competing objectives (e.g., biodiversity, human well-being) in the presence of diverse stakeholder preferences and uncertainty of decision outcomes. Structured decision making (SDM) has emerged as an effective tool for addressing such contexts. SDM applications for natural resources often focus on evaluating biological objectives with rigorous models while social objectives are less frequently included and rigorously evaluated. SDM has not been applied to a pervasive and challenging conservation issue: roads. Roads present multiple threats to nearby wildlife populations at various scales; however, management attempting to reduce impacts to wildlife must also consider roads as valuable infrastructure important to people’s daily lives and local economies. We describe the co-development of a multi-objective SDM framework with local stakeholders to identify management decisions using the diamondback terrapin (Malaclemys terrapin) as a focal species and the Jekyll Island Causeway (Jekyll Island, Georgia, USA) as a model system. We also demonstrate the novel practice of integrating human dimensions research, capturing the preferences of large stakeholder groups, into an SDM framework to more accurately predict social outcomes of decisions.
Results/Conclusions
When considering management decisions for the JIC, stakeholders identified five fundamental objectives: maximizing terrapin persistence, human safety, patron satisfaction, and transferable knowledge (learning), and minimizing net cost. We used ecological and human dimensions data, as well as expert opinion, to model the effects of 20 alternative management strategies on objective outcomes. Strategies were comprised of a unique combination of actions designed to impact objectives, including roadside barriers, on-road signage, education programs, and predator and vegetation management. Decision analysis showed that i) stakeholders varied in their preferences for objectives, but terrapin persistence and human safety were most important, on average, ii) the best-performing strategy overall did not rank best for any one objective but included complementary actions (roadside barriers, warning signage, conservation awareness campaigns) that allowed it to perform well across most objectives, and iii) the best strategy was insensitive to stakeholder-specific preferences. Our results provide direct recommendations for addressing terrapin conservation and socioeconomic goals for Jekyll Island. Furthermore, our study demonstrates the efficacy of applying SDM to road management contexts and the benefit of using human dimensions data to more accurately measure preferences of diverse stakeholder groups and model decision-outcomes.