Characterization and ecological significance
of a seed bank from the Upper Pennsylvanian
Wise Formation, southwest Virginia
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1 |
Department of Biological Sciences, East Tennessee State University, PO Box 70300, Johnson City, TN 37614, USA |
2 |
Department of Biological Sciences, University of Texas of the Permian Basin, 4901 E. University, Odessa, TX 79762, USA |
3 |
Associate Vice President, Office of Research and Sponsored Programs, California State University, Titan Hall, 2nd Floor, 1121 North State College Blvd., Fullerton, CA 9283, USA |
Online publication date: 2017-12-19
Publication date: 2017-12-19
Acta Palaeobotanica 2017; 57(2): 165–175
ABSTRACT
Soil seed banks are important to the maintenance and restoration of floras. Extant seed banks
exhibit unique characteristics with regard to the distribution of seed size and seed density. Seeds were recovered
from the Upper Pennsylvanian Wise Formation in southwest Virginia. Structurally preserved seeds were also
examined from coal balls of the Pennsylvanian Pottsville and Allegheny Groups, Ohio. The size distribution of
the seeds from the Wise Formation is similar to that of structurally preserved seeds of the Upper Pennsylvanian
Pottsville and Allegheny Group coal balls. In contrast, the seed size distributions in extant wetland, grassland,
woodland and forest habitats are significantly narrower than that of seeds from the Pennsylvanian seed banks.
Larger seeds are less dependent on light for germination, and aid in seedling establishment more than smaller
seeds, especially in dense stable forests where disturbance events are rare. Large seed size may contribute to
increased seed longevity, which reduces the effect of environmental variability on seed germination and development.
The significantly larger size of the Palaeozoic seeds may have imparted an advantage for seedling establishment
in the dense Palaeozoic forests. The preponderance of large seeds may be a result of the absence of large
seed predators (e.g. herbivorous tetrapods), and may have been an evolutionary strategy to minimize damage to
the embryo from a predator population dominated by small invertebrates with chewing or sucking mouthparts.
The estimated seed density of 192 seeds/m2 in the Palaeozoic seed bank falls within the range of modern seed
banks, but at the lower end of modern seed bank densities in a variety of habitats.