Abstract Detail

The evolution and ecology of aquatic bryophytes

Benscoter, Brian [1].

Bryophyte community feedbacks to ecosystem structure and function in boreal peatlands.

Boreal peatlands are ecosystems dominated by bryophytes, both compositionally and functionally. Bryophytes, particularly Sphagnum mosses, occupy extensive portions of the boreal peatland ground layer as well as that of many lowland boreal forests. These mosses form thick soil organic layers contributing substantially to the regional and global terrestrial carbon (C) pool, with boreal peatlands comprising more than a third of the global terrestrial C stock. Bryophyte species distribution patterns within peatlands are the product of autogenic and allogenic forces, primarily centered on moss adaptations for and spatial distributions of soil moisture conditions. The strong spatial heterogeneity of moss and lichen communities along soil moisture gradients also produces similar heterogeneity in ecosystem C cycling due to species-specific differences in peat formation processes. Trade-offs between productivity and decomposability help to reinforce spatial patterns of structure and composition through differential peat accumulation and column elevation feedbacks to edaphic conditions. Such feedbacks also influence the likelihood and behavior of wildfire in peatlands. Moisture-retaining moss communities produce soil fuel conditions that restrict combustion while communities prone to drying have increased vulnerability to burning. The severity of combustion affects community recovery post-fire, with relict unburned communities recovering to pre-fire conditions much faster than more severely burned communities. Differential trajectories of community recovery post-fire will similarly produce differential patterns of ecosystem C exchange. Early post-fire, peatlands are sources of atmospheric C due to decreased bryophyte cover. As the community recovers, peatlands become C sinks, although autogenic stress and community change can reduce or even reverse peat C storage.  These late-succession autogenic changes as well as altered climate can have positive feedbacks to fire severity, increasing the vulnerability of peatlands and their C storage capacity. Therefore, it is important to understand how drivers of bryophyte communities may change under future scenarios and the implications these may have for wildfire regimes and peatland C cycling. 

1 - Florida Atlantic University, Biological Sciences, 3200 College Ave, Davie, FL, 33314, USA

Keywords:
Sphagnum
fire
carbon sink
microtopography.

Presentation Type: Symposium or Colloquium Presentation
Session: SY02
Location: Payette/Boise Centre
Date: Monday, July 28th, 2014
Time: 4:15 PM
Number: SY02007
Abstract ID:719
Candidate for Awards:None