Classification and environmental correlates of tidal wetland vegetation in Nova Scotia, Canada

Abstract

We numerically classified tidal wetland vegetation and determined the relationships between variation in plant species composition and environmental factors. Sampling was conducted at eight sites along a range of tidal magnitudes (<2 to >14 m). Cluster analysis revealed seven distinct salt or brackish marsh plant associations, usually dominated by a single graminoid species. Redundancy analysis showed continuous variation among community units and identified inundation time, elevation, soil salinity, and organic matter content as key correlates of plant community patterns. Associations detected were similar to those found in New Brunswick’s Bay of Fundy and Northumberland Strait wetlands, and to those farther south in northern New England, but two new brackish associations were also identified within this study (Juncus balticus Willd. – Festuca rubra L. and Spartina pectinata Link). Although elevation is understood to drive vegetation types in salt marshes in the region, here we show that salinity can differentiate vegetation types at the same elevation. These data provide a quantitative baseline and allow for better predictions of tidal wetland ecological restoration trajectories in Nova Scotia.