The effects of nitrogen deposition on plant-soil interactions in European raised bogs – a review

Abstract

Nitrogen deposition as a result of agriculture and fossil fuel burning is globally affecting a wide range of ecosystems. Including vulnerable and valuable raised bogs. These peatlands provide important ecosystem services, like carbon storage and water buffering. This review focussed on the effect of nitrogen deposition on the plant soil interactions in European raised bogs. Sphagnum mosses are the dominant species in raised bogs, they are hard to decompose and create a wet and acidic environment. They are able to filter nitrogen from the air, essentially filtering out the nitrogen before it can reach the soil. This does however negatively affect the growth and survival of the Sphagnum mosses. Only after Sphagnum is saturated, the nitrogen gets into the soil which stimulates vascular plant growth. Which can shift the vegetation from Sphagnum dominated to vascular plant dominated and increases the amount of easily degradable plant litter. These changes also cause a change in microbial community and increases decomposition. These responses limit the ecosystem services of raised bogs, limiting the amount of carbon that is sequestrated and the amount of water that can be stored. These systems are however able to recover, which means conservation and restoration of raised bogs is possible. To understand these processes better, it is important to research why Sphagnum declines as a result of nitrogen deposition and how different microbial groups are influenced by nitrogen directly. Limiting nitrogen deposition globally is also important so raised bogs can keep sorting carbon and buffering water.