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RESOURCE CONGRUENCE AND FOREST REGENERATION FOLLOWING AN EXPERIMENTAL HURRICANE BLOWDOWN
Author(s) -
Carlton G. C.,
Bazzaz F. A.
Publication year - 1998
Publication title -
ecology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.144
H-Index - 294
eISSN - 1939-9170
pISSN - 0012-9658
DOI - 10.1890/0012-9658(1998)079[1305:rcafrf]2.0.co;2
Subject(s) - boiler blowdown , canopy , environmental science , ecology , spatial ecology , ecosystem , spatial heterogeneity , biology , geology , inlet , geomorphology
Catastrophic uprooting of forest canopy trees creates mounds, pits, and other microsites that provide opportunities for regeneration of particular species. We measured environmental factors on five types of microsites created by simulated blowdown of a mixed deciduous forest in central New England, United States. We then estimated spatial variation in resource levels and quantified congruence among different resources at each site. Effects of simulated blowdown on light levels and CO 2 concentrations were more pronounced after three years than effects on nitrogen availability and other soil resources. Spatial heterogeneity in light levels and net nitrification rates was greater in the blowdown, but heterogeneities of soil organic matter concentration and net mineralization rates were greater in the undisturbed forest. Availability of nitrate, a limiting resource in most New England forests, was low on mounds and in pits, but high on the vertical portion of forest floor resulting from uprooting of canopy trees. At a spatial scale relevant to seedlings, resource congruence was greater in the undisturbed forest than in the experimental blowdown, primarily because of the effects of blowdown on light levels. Congruence in the blowdown increased with an increase in spatial scale, but congruence in the undisturbed forest was similar at both spatial scales. Seedling growth of two birch species was correlated with light levels and with congruence among soil resources. This study shows that immediate disturbance effects on microtopography and light levels determine recruitment patterns of colonizing species, with changes in soil resource levels influencing later community development. Furthermore, some species appear to respond to resource congruence, which may provide an additional dimension to the regeneration niche.