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Making it big in bottomlands: regeneration strategies of intermediate species.
Collins, Beverly*,1, Battaglia, Loretta2, 1 Savannah River Ecology Laboratory, Aiken, SC2 Southern Illinois University Carbondale, Carbondale, IL
ABSTRACT- The dynamics of bottomland hardwood (BLH) forests are controlled largely by plant response to heterogeneity generated by flooding and frequent windstorms, which open the canopy and generate local microtopographic variation. We examined regeneration strategies of canopy species relative to flooding and light heterogeneity in BLH forests. Highly flood-tolerant species are typically shade-intolerant and grow quickly enough to avoid inundation. Most shade-tolerant species are flood-intolerant and restricted to drier portions of the floodplain. In contrast, highly shade-intolerant species regenerate in large openings and colonize substrates over a range of flooding conditions. Between these extremes, intermediate species comprise the bulk of BLH canopy. These species may 1) have broad tolerances, with regeneration driven by chance, dispersal, or biotic interactions or 2) exhibit small-scale sorting over environmental heterogeneity and trade-offs in plant traits over life history stages. We synthesized information for common intermediate bottomland species, including Liquidambar styraciflua, Quercus michauxii, and Q. pagoda, and propose a conceptual model of regeneration strategies linked to species coexistence and regeneration patterns in complex, highly productive bottomland forests.
Key words: regeneration, bottomland hardwood forest