Distribution, species composition and management implications of seed banks in southern New England coastal plain ponds

TitleDistribution, species composition and management implications of seed banks in southern New England coastal plain ponds
Publication TypeJournal Article
Year of Publication2009
AuthorsNeill, Christopher, Bezerra Maira Ometto, MCHORNEY RICHARD, and O’Dea Claire B.
JournalBiological Conservation
Pagination1350 - 1361
Date Published7/2009
Keywordsfreshwater wetland, pond shore, seed germination

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 coastalplainponds 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 seedbanks, (2) determine if hydrologic status as permanent and ephemeral ponds led to differences in seedbanks, 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 nine ponds. Native species dominated pond-shore seedbanks and made up 89–100% of all species. There was high overlap in seedbankcomposition 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 seedbank 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 coastalplainpond plants contained in pond sediment seedbanks should be implemented across pond hydrologic classes and across a wide geographic area. Shoreline seeddistributions 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 seedbanks 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.