Defining restoration goals for the Humboldt Coastal Nature Center, Manila, California, based on an analysis of ecological processes in coastal dunes

Invasive plants have had significant impacts on the dune ecosystem on the North Spit of Humboldt Bay, where they have modified ecological processes. A large area of these dunes lies adjacent to the community of Manila, including Friends of the Dunes' Humboldt Coastal Nature Center, where restoration activities are under close public scrutiny. Management recommendations for the Humboldt Coastal Nature Center were identified through an analysis of key ecological processes: examination of vegetation succession using a Geographic Information System (GIS), mapping invasive plants and endangered plants with a Global Positioning System (GPS), investigating dune morphology with local experts, and gathering input from residents of the community of Manila on how they feel about restoration activities. Findings from the analysis show that the Humboldt Coastal Nature Center landscape went from being composed of 32.4 ha of active coastal dunes in 1948 to having only 7.9 ha of active coastal dunes in 2009. It appears that vegetation began stabilizing some of the active dune areas through natural succession between 1954 and 1970, and it is plausible that invasive plants, which covered 20.7 ha by 2009, sped up the process of this stabilization. Along with the stabilization of the dunes, geomorphic processes have been impeded by European beachgrass invading the foredune which cuts off inland sand supply from the beach. The main concern from residents of the community of Manila was that restoration activities could compromise their safety, but investigation of geomorphic processes found that restoration activities could strengthen the community's defense against storm waves and tsunamis. From these findings, management recommendations for the Humboldt Coastal Nature Center were compiled in a GIS. Management recommendations focused on restoring ecological processes and native vegetation across the entire property, and restoring geomorphic processes in the foredune area. Furthermore, recommendations suggested adaptive management strategies for dune management near human communities and identified areas of further research that will benefit coastal dune restoration efforts in the region and beyond.