The Future of Oaks in the Santa Monica Mountains: A Case Study in Using Remote Sensing Data for Species Distributions Models

The Woolsey Fire began on November 8, 2018, and lasted for almost two weeks, during which it burned almost 100,000 acres of valuable landscape and habitat, including a vast area of woodland. The persistence of key woodland species provides aesthetic, monetary, and ecological value to the landscape through carbon sequestration, air temperature moderation, and erosion mitigation, among other ecosystem services. This study investigated the impact of the Woolsey Fire on native woodland species distributions and identified areas suitable for restoration within the Santa Monica Mountains National Recreation Area. Species distribution models for four vegetation guilds of interest were created using the MaxEnt software package that utilized historic and projected climate variables, and topographic variables. Climate data for the species distribution models were acquired from the NASA Earth Exchange (NEX) Downscaled Climate Projections (NEX-DCP30) dataset, which included outputs for the representative concentration pathways (RCP) scenarios developed by the Intergovernmental Panel on Climate Change. We used monthly averages of precipitation flux, maximum near-surface air temperature, and minimum near-surface air temperature for historical, RCP 4.5, and RCP 8.5 scenarios. Topographic variables such as slope, aspect, and flow accumulation were acquired from the Shuttle Radar Topography Mission. Models with high predictive capabilities indicated by area under the receiver-operator curve (AUC) values (> 0.7) were created using topographic and climate variables in combination with species occurrence data provided by the National Park Service that utilized remotely sensed and in situ observations. These accurate woodland species distribution models can be used to assist local land managers as they draft planting priority plans to continue sustainable management of the recreation area.