Mapping oak diversity and habitat suitability using multi-species niche modeling

Oak ( Quercus ) diversity is a defining feature of North American forests, comprising over 75% of the region's vegetation. Oaks play a vital role in supporting numerous wildlife species by providing essential food and habitat resources, while also contributing to carbon storage, soil stabilization, and cultural and economic values. Arkansas, with its highly diverse biogeography, offers suitable conditions for a wide range of oak species, leading to the formation of varied vegetation communities. The purpose of this study is to assess the diversity (species richness) of the Quercus genus across the state of Arkansas using multi species niche modeling. Geographic coordinates of 5,987 herbarium records, representing 26 native Oak species, were compiled. We employed an ensemble species distribution modeling approach to predict suitable habitat areas for oak species and to identify hotspots. Our results showed that mean temperature of driest month, precipitation of warmest month, and mean diurnal range contributed > 80% the model prediction. The highest oak richness in Arkansas was found in Crowley's Ridge and Mississippi Valley Loess Plains, each supporting 20 Quercus species, followed by Arkansas River Valley and Ozark highlands with 18 species each. Considering growing concerns over oak forest decline due to anthropogenic and climate change, this study offers valuable insights for conservation, assessment, management strategies, and silviculture planning of oak species in the region.