Canadian Forest Service Publications
Dissimilar bacterial and fungal decomposer communities across rich to poor fen peatlands exhibit functional redundancy. 2015. Haynes, K.M.; Preston, M.D.; McLaughlin, J.W.; Webster, K.; Basiliko, N. Canadian Journal of Soil Science 95 (3): 219-230.
Year: 2015
Issued by: Great Lakes Forestry Centre
Catalog ID: 36396
Language: English
Availability: PDF (request by e-mail)
Abstract
Climatic and environmental changes can lead to shifts in the dominant vegetation communities present in northern peatland ecosystems, including from Sphagnum- to vascular-dominated systems. Such shifts in vegetation result in changes to the chemical quality of carbon substrates for soil microbial decomposers, with leaves and roots deposited in the peat surface and subsurface that potentially decompose faster. This study characterized the bacterial and fungal communities present along a nutrient gradient ranging from rich to poor fen peatlands and assessed the metabolic potential of these communities to mineralize a variety of organic matter substrates of varying chemical complexity using substrate-induced respiration (SIR) assays. Distinct microbial communities existed between rich, intermediate and poor fens, but SIR in each of the three sites exhibited the same pattern of carbon mineralization, providing support for the concept of functional redundancy, at least under standardized in vitro conditions. Preferential mineralization of simple organic substrates in the rich fen and complex compounds in the poor fen was not observed. Similarly, no preference was given to “native” organic matter extracts derived from each fen, with microbial communities opting for the most bioavailable substrate. This study suggests that soil bacteria and fungi might be able to respond relatively rapidly to shifts in vegetation communities and subsequent changes in the quality of carbon substrate additions to peatlands associated with environmental and climatic change.
Plain Language Summary
In northern peatland ecosystems, climatic and environmental changes can lead to shifts in the dominant vegetation communities. This results in changes to the leaves and roots deposited in the peat surface and subsurface, which can affect the rate of decomposition by soil microbes. We characterized the bacterial and fungal communities present along a nutrient gradient, ranging from rich to poor fen peatlands. We assessed the metabolic potential of these communities to mineralize a variety of organic matter substrates. We found that distinct microbial communities existed in the rich, intermediate and poor fens but the three sites exhibited the same pattern of carbon mineralization. This study suggests that soil bacteria and fungi might be able to respond relatively rapidly to shifts in vegetation communities and subsequent changes in the quality of carbon substrate additions to peatlands associated with environmental and climatic change.