Ecological Responses of Bryophytes to Changing Climate
Vitt, Dale H. .
Boreal Peatlands: Climatically Sensitive Ecosystems Dominated by Boreal Peatlands: Climatically Sensitive Ecosystems Dominated by Bryophytes.
BROADLY defined, peatlands are ecosystems in which production is greater than decomposition – the result is accumulation of peat and sequestration of carbon from the atmosphere. Peatlands occupy about 24% of the boreal forest and carbon-rich peatland soils represent about 1/3 of the world’s soil carbon. Instantaneous release of this store of carbon into the atmosphere would increase present-day atmospheric CO2 concentrations by more than 50%. A large percentage of this stored carbon is bryophytic -- mainly Sphagnum in bogs and poor fens and true mosses in rich fens. Conceptually, bryophyte responses to both temperature and precipitation changes are not parallel to those of vascular plants, making prediction of ecosystem responses difficult. In this presentation, I discuss four aspects of peatland response to environmental changes that have has ramifications on bryophyte survival and function. 1) Peatland responses to Holocene climatic changes were dynamic and involved functional responses in dominant bryophyte species. These changes are documented at the site level and at the regional level. 2) Bryophyte re-establishment and subsequent successful growth are fundamental to the re-establishment of peatland carbon sinks after wildfire. Our recent data collected in boreal Canada describe the trajectory of net ecosystem exchange relative to bryophyte re-establishment. 3) Bryophyte responses to recent boreal forest droughts clearly set the stage for our understanding of how bryophyte-dominated ecosystems will potentially respond to increasing drought. And 4) response surface modeling has provided glimpses into how bryophyte species will react to higher CO2 atmospheric concentrations. In conclusion, the functioning of peat accumulating ecosystems may be strongly affected by the internal responses of ground layer bryophytes.
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1 - Southern Illinois University, Department of Plant Biology, 1125 Lincoln Drive, Carbondale, Illinois, 62901-6509, USA
Presentation Type: Symposium or Colloquium Presentation
Date: Monday, July 31st, 2006
Time: 11:15 AM