Inland salt marsh ecology and the restoration of rare plant communities on a solvay waste site: A functional approach

This dissertation examines---from a functional perspective---processes of assembly and restoration of inland salt marshes, a globally impleriled plant community. This functional approach is taken to describe the ecophysiological underpinnings of inland salt marshes and provide a rigorous basis of design for restoration.;In New York's three remaining inland salt marshes, species composition varied primarily along interacting gradients of soil electrical conductivity and Na:K, and flooding duration. Variation in species relative abundance along these gradients was primarily driven by species location on the salinity tolerance axis---a syndrome of traits providing efficient water use and tolerance of sodium toxicity. Species that scored high on this axis were competitively excluded from non-saline settings due to tradeoffs in nitrogen allocation between salinity tolerance and competitive ability. Plant leaf size also played a key role in the sorting of species, with small-leaved species increasing in presence or relative abundance as soil sainity and pH increased and total N decreased. This leaf size pattern was repeated at a saline restoration site, the Solvay Settling Basins (SSB), where biomass production and evapotranspiration of experimental plant communities were correlated with community-level leaf size. As soil salinity increased, the slope between community-level leaf size and biomass production shifted from positive to negative, and partial correlation analyses suggested that community-level leaf size drove biomass production via plant survivorship under saline conditions and via resource use (i.e., light interception and evapotranspiration) under non-saline conditions. Leaf size explained patterns of species relative abundance along environmental gradients at a 2.1 ha restoration project where rare plant communities restricted to highly stressful habitats (i.e., inland salt marsh, marl fen, alvar grassland, and Great Lakes dune) were used to restore a largely barren Solvay waste site. These rare native plant communities were found to be amenable to restoring ecological function and natural heritage value to areas with barren/unproductive soils formed from Solvay waste. Inland salt marsh species exhibited high levels of survivorship and moderate levels of productivity on SSB soils with salinities similar to that of seawater. The highly stressful soil conditions present at the SSB offer opportunities to restore rare plant communities that were once abundant in Central New York but are currently imperiled.;Keywords: alvar grassland, ecological restoration, Great Lakes Dune, marl fen, plant traits, restoration ecology, salinity, salt tolerance, Solvay Settling Basins, Solvay Waste Beds...