The U.S. Geological Survey provides science support to land managers within the Department of the Interior. This support often requires that ecological and biological analyses respect specific management objectives in light of feasible organization options and other practical constraints. Increasingly, this support also requires that complex and interacting external forces (e.g., climate) be considered in the analysis. While state and transition simulation modeling (STSM) can be used as a stochastic modeling approach, it can also be utilized as an organizing framework to integrate external forcings, species- or habitat-specific ecological traits, and management scenarios. We will present STSM as such a framework and give examples where external forcing of climate, fire, and invasive species are integrated with management options for managing key resource on Department of the Interior lands.
Results/Conclusions
A recent case study explored integrated STSM to predict distribution of sagebrush plant community phases and states over time with relationships between invasive cheatgrass and climate model outputs and their effects on the number of ecological disturbance occurrences per year. Another study focusing on whitebark pine in the Greater Yellowstone Ecosystem linked an STSM to a correlative species distribution model in order to reproduce historical observations related to mountain pine beetle mortality and project whitebark pine population trends into the future under various climate and management scenarios. STSMs of invasive buffelgrass in the Tuscon area were able to highlight the tradeoff between inventory and monitoring, efficiencies gained with different management strategies, and the potential influence of fire and climate change on the landscape in the future. Sensitivity analyses in all STSMs highlighted knowledge gaps of importance to decision making. All of these case studies highlight the utility of STSMs to inform management strategies and future research directions.