Event Title

Post-Fire Microsites and Effects of Bryophytes on Germination and Establishment of Conifers and Early-Seral Species

Event Website

http://www.nafew2009.org/

Start Date

22-6-2009 11:10 AM

End Date

22-6-2009 11:30 AM

Description

Bryophytes are often the dominant vegetation layer with patchy distributions in early post-fire succession. Little is known about early-seral bryophyte habitat requirements or their influence on germination and establishment of vascular plants. In the presence of seed or spore sources, microsite conditions can affect distributions of bryophytes, conifers and early-seral vegetation. The objectives of this study were to examine the distribution and characteristics of microsites following post-fire restoration, habitat requirements for establishment of post-fire bryophytes, and to compare germination and establishment of vascular plants between bryophyte and bare soil seedbeds. An observational study and greenhouse seeding trial were utilized to address these objectives. Post-fire microsites were heterogeneous, partially due to the existence of pre-fire legacies, including downed wood, snags, and sprouting vegetation. Post-fire bryophytes occupied specific microsites that generally occurred on undisturbed soil with low to moderate litter and overstory cover. Impacts of bryophyte seedbeds on germination and growth of vascular plants differed by bryophyte type and vascular plant species. Germination of early-seral vascular plants or conifers was not affected by burnt bryophyte seedbeds, but Pinus ponderosa germination was higher in unburnt bryophytes compared to other seedbeds in the greenhouse. Ceanothus sanguineus and Chamerion angustifolium had reduced growth in burnt bryophyte seedbeds compared to other seedbeds while conifers did not. Pseudotsuga menziesii, Abies concolor and Pinus ponderosa had higher shoot biomass in unburnt bryophyte seedbeds than other seedbeds. Competitive interactions appeared to occur between early-seral bryophytes and vascular plants but not between late-seral bryophytes and vascular plants. Fundamental differences exist between early-seral and late-seral bryophytes that could cause this discrepancy including dominant bryophyte lifeforms, mat density, and mat depth. Restoration treatments have the potential to alter successional patterns following fire due to alteration of microsite characteristics, which impact early-seral bryophyte distributions and germination and establishment of vascular plants.

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Jun 22nd, 11:10 AM Jun 22nd, 11:30 AM

Post-Fire Microsites and Effects of Bryophytes on Germination and Establishment of Conifers and Early-Seral Species

Bryophytes are often the dominant vegetation layer with patchy distributions in early post-fire succession. Little is known about early-seral bryophyte habitat requirements or their influence on germination and establishment of vascular plants. In the presence of seed or spore sources, microsite conditions can affect distributions of bryophytes, conifers and early-seral vegetation. The objectives of this study were to examine the distribution and characteristics of microsites following post-fire restoration, habitat requirements for establishment of post-fire bryophytes, and to compare germination and establishment of vascular plants between bryophyte and bare soil seedbeds. An observational study and greenhouse seeding trial were utilized to address these objectives. Post-fire microsites were heterogeneous, partially due to the existence of pre-fire legacies, including downed wood, snags, and sprouting vegetation. Post-fire bryophytes occupied specific microsites that generally occurred on undisturbed soil with low to moderate litter and overstory cover. Impacts of bryophyte seedbeds on germination and growth of vascular plants differed by bryophyte type and vascular plant species. Germination of early-seral vascular plants or conifers was not affected by burnt bryophyte seedbeds, but Pinus ponderosa germination was higher in unburnt bryophytes compared to other seedbeds in the greenhouse. Ceanothus sanguineus and Chamerion angustifolium had reduced growth in burnt bryophyte seedbeds compared to other seedbeds while conifers did not. Pseudotsuga menziesii, Abies concolor and Pinus ponderosa had higher shoot biomass in unburnt bryophyte seedbeds than other seedbeds. Competitive interactions appeared to occur between early-seral bryophytes and vascular plants but not between late-seral bryophytes and vascular plants. Fundamental differences exist between early-seral and late-seral bryophytes that could cause this discrepancy including dominant bryophyte lifeforms, mat density, and mat depth. Restoration treatments have the potential to alter successional patterns following fire due to alteration of microsite characteristics, which impact early-seral bryophyte distributions and germination and establishment of vascular plants.

http://digitalcommons.usu.edu/nafecology/sessions/fire_effects/4