Evaluating the Ecological Sustainability of a Pinyon-Juniper Grassland Ecosystem in Northern Arizona

In order to develop strategic land management plans, managers must as- sess current and future ecological conditions. Climate change has expanded the need to assess the sustainability of ecosystems and predict their conditions under different climate change and management scenarios using landscape dynamics simulation models. We present a methodology for developing a state-and-transition model (STM) with the Vegetation Dynamics Development Tool (VDDT), using outputs from the Forest Vegetation Simulator (FVS). Preside, a recently developed accessory to the FVS program, is used to process and report FVS outputs in terms of succession prob- abilities and residence times for each STM. We've applied these tools with a case study based on the pinyon-juniper grassland ecosystem in northern Arizona. After applying local probability values for natural growth, contemporary fire, insect and disease, and management activities, VDDT simulations were conducted to project future ecosystem conditions including carbon accounting. Finally, we also describe how these models can be retooled with FVS support to reflect the effects of climate change so that managers can consider adaptation and mitigation strategies.