Integrating habitat suitability, disturbance, and biotic interactions into the ecological restoration of the saguaro (Carnegiea gigantea) in drylands of the southwest of the United States and northern Mexico

This study proposes a combined approach encompassing habitat suitability, biotic interactions, and disturbance to identify high-value restoration areas (HVRA) for the saguaro (Carnegiea gigantea, Cactaceae)-that is, areas with high habitat suitability for the saguaro and species that favor its establishment, growth, and dispersal (hereafter associated species), which were damaged by wildfires. We used species distribution modeling to produce habitat suitability maps for the saguaro and associated species (four nurse-plants and 63 animals). We used Hot Spot Spatial Analysis to estimate hotspots of habitat suitability for the saguaro (HSS), nurse species (HNS), and associated animal species (HAS), and Moderate Resolution Imaging Spectroradiometer to identify burned (disturbed) areas. Finally, we estimated the overlay across habitat suitability hotspots and burned areas to identify HVRA. Overall, HSS, HNS, and HAS were mostly distributed across the northeast part of the Sonoran Desert. Results also indicated a strong overlay among HSS, HAS, and HNS. For the first time, this study provides distributional maps using biotic and bioclimatic variables for the giant saguaro cactus. Beyond saguaro conservation, our study can assist conservationists and managers in planning and implementing post-fire regeneration strategies (e.g. monitoring the spread of exotic invasive grasses across burned areas). HVRA can also aid managers in preserving undisturbed priority areas, managing burned landscapes, prioritizing restoration activities, and evaluating post-fire vegetation responses.