Arbuscular Mycorrhizal Fungi Colonization Response to Dike Removal in the Salmon River Estuary

Abstract

Arbuscular mycorrhizal fungi (AMF) form symbiotic relationships with wetland plants and are important to the restoration of coastal estuaries. The purpose of this study was to assess the presence and colonization of arbuscular mycorrhizal fungi in Distichlis spicata from three formerly diked areas of the Salmon River Estuary to determine an initial understanding of the mycorrhizal community in tidal wetlands post-restoration. AMF were present in all four sample areas and total colonization ranged on average 39-72%. The reference site had the lowest levels of total colonization, which is contrary to the findings of studies of younger wetland restorations. Most importantly, arbuscular colonization was not significantly different between any sites suggesting that the levels of nutrient exchange in the restoration sites were comparable to reference conditions. Lower soil pH of the restored site due to increased oxidation and acid sulfates could increase AMF nutrient storage and communication with host plants by increasing vesicular colonization. The levels of AMF colonization and soil characteristics showed that the Salmon River Estuary is nearly restored since dike removal. The proximity and connectivity of restoration sites to disturbed sites can potentially influence the AMF community and expedite the restoration process. Existing AMF communities and native fungal inoculum can influence the succession of plant species in restoration sites and should be considered in wetland restoration projects. AMF are incredibly dynamic, resilient, and influential organisms with enormous potential in wetland restoration ecology.