Buried seeds that germinate during periods of low water or water level drawdown can play
important roles in shaping plant community composition, community dynamics and species
richness in ecosystems with fluctuating water levels. Northeastern US coastal plain ponds have
fluctuating water levels and contain a characteristic shoreline flora that contains many rare
plants. The objectives of this study were to: (1) test whether geographically distant ponds in
Cape Cod and Martha’s Vineyard had distinct seed banks, (2) determine if hydrologic status as
permanent and ephemeral ponds led to differences in seed banks, and (3) examine seed diversity
and seed abundance across gradients of shoreline elevations and sediment characteristics. Viable
seeds of 45 plant species were identified from 9 ponds. Native species dominated pond-shore
seed banks and made up 89 to 100% of all species. There was high overlap in seed bank
composition across hydrological classes and geographic regions. One hydrological class captured
73-76% of total species and one geographical region captured 69-78% of the total species
recovered from the entire suite of seed bank samples. Seeds were relatively evenly distributed
along the shorelines of ephemeral ponds but seed diversity and abundance were lower at low
elevations in permanent ponds. Results suggest that strategies to protect pond shorelines to
capture maximum diversity of coastal plain pond plants contained in pond sediment seed banks
should be implemented across pond hydrologic classes and across a wide geographic area.
Shoreline seed distributions indicate that ground-water withdrawals or climate changes that
lower pond water levels in permanent ponds will reduce the diversity and abundance of plants
recovered from seed banks by shifting water levels to a shoreline zone of high sediment organic
matter where seed densities are lower. This effect will be much less in ephemeral ponds where
seed diversity and abundance on pond bottoms was high.