In annual species, seeds are the perennating organ. Plants occupy new habitats via sexual reproduction and seed dispersal, and asexual reproduction in close proximity to the parent plant. 2007), and these patches are interspersed with the remaining forest canopy, influencing the ease, timing, and type of post-fire colonization.
Invasión 1997 Patch#
For example, there is large variation in patch sizes of newly regenerated early seral conditions (Hessburg et al. Intact forest canopies may filter seed rain and reduce seed influx, while high severity fires are more open to invasion by seed dispersal.įorest fires and other ecological processes produce complex patterns of vegetation on the landscape. Our results suggest that high severity fire plots are more porous to seed rain than low severity plots. In these paired Tyee patches the average number of new seed species (species not found in the extant plot vegetation) was greater for high severity than low severity fire. Seed rain richness was greater in Tyee high severity patches than paired low severity fire patches. Seed rain at the Fischer Fire patches (sampled one year after the fire) was predominantly composed of annual species, while that of the Tyee Fire patches (sampled nine years after fire) was predominantly perennial species. At the Tyee Fire Complex, the total seed production for each of the two fire severities was similar, but the period of maximum seed dispersal was later for high severity than low severity fire.
The high severity fire patches in the Fischer Fire Complex had a higher total seed production than low severity fire patches of the same complex. Unburned plots had the lowest average seed production. Using seed traps, we studied impacts of fire severity on timing of seed dispersal, total seed rain, and seed rain richness in patches of high and low severity fire and unburned Douglas-fir ( Pseudotsuga menziesii) forests in the Fischer and Tyee fire complexes in the eastern Washington Cascades. Forest seed dispersal is altered after fire.
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