Southeast Farallon Island seed bank characterization

Characterization of soil seed banks ('seed banks' hereafter) are important to increased understanding of vegetation communities and can shed light on their true diversity as well as their response to and recovery from disturbance. These factors help guide effective environmental management, especially in disturbed ecosystems. We performed the first characterization of the seed banks on Southeast Farallon Island, assessing species richness, density, distribution, and temporal variation, and through these the status of native and nonnative seed banks on the island. These were compared with the aboveground vegetation in order to reveal patterns within and between the above- and belowground communities. Results show that the seed banks and aboveground vegetation were heavily impacted by non-native species in richness, density, and cover, although native species remain present and widespread in both systems. Seasonal variation characteristic of Mediterranean annual vegetation communities was exhibited in both the seed banks and aboveground vegetation, although no yearly variation was detected. Results suggest the existence of a largely homogenous seed bank across the island, of which the annual expression in the aboveground vegetation is dependent upon numerous factors including disturbance, environmental factors, germination cues, and seed input from previous seasons. By revealing a widespread and robust presence of native seeds in the seed banks, this study can help guide effective restoration of native vegetation on SEFI and provide a baseline dataset that future studies can use to assess impacts of ongoing and proposed management actions on Southeast Farallon Island and other temperate island ecosystems.