The role of coastal ecotones: a case study of the salt marsh/upland transition zone in California

Abstract

Summary1 Ecotones, the transition zones between adjacent ecological systems, may intensify or concentrate the flow and processing of materials and organisms between systems. 2 To determine whether the salt marsh/upland transition zone is an ecotone, both in functioning as a habitat, as well as concentrating materials and organisms, I conducted an extensive survey of 12 marsh /upland transition zones in the Pt Reyes area of California. 3 The high saltmarsh was identified as an ecotone, with biological and physical conditions distinct from the adjacent marsh plain and upland. It supports a unique plant assemblage and greater total soil nitrogen than the adjacent upland. 4 Taxonomic richness patterns did not reflect changes in habitat spatial characteristics (e.g. ecotone area, ecotone area/perimeter), instead showing a quadratic correlation along the gradient, with increased diversity of both plants and spiders in the ecotone. Spider richness was enhanced with increased vegetation complexity, which was greatest in the ecotone. 5 This study presents empirical evidence that suggests coastal marsh/upland ecotones harbour increased diversity and may concentrate nitrogen pools, thereby highlighting the need for further research investigating the relationship between landscape connections and the coupling of species and biogeochemical processes.

Distribution and Invasion Potential of Limonium ramosissimum subsp. provinciale in San Francisco Estuary Salt Marshes

“…Declining moisture across this vertical range is well established, but our soil moisture values were lower than similar studies. Traut (2005) found moisture decreased from 40% to 15% from mid-marsh into upland soils in June and July. St.…”

“…Omer 2004), at Pt. Reyes National Seashore (Traut 2005), in Elkhorn Slough (Harvey et al 1978;Byrd and Kelley 2006), and in cooler climates (Oregon: Seliskar 1985), but contrasting with patterns in southern California marshes where soil is hypersaline during summer months through the transition zone up to maximum high water (Callaway et al 1990). Soil moisture, too, decreased with elevation across LIRA's vertical range.…”

“…For example, in San Pablo Bay (northern estuary), Mahall and Park (1976) found that maximum salinity occurred just above MHW (which corresponded in their study within the pickleweed plain) and decreased landward, regardless of season. Similarly, Traut (2005) found soil salinity decreased from the pickleweed dominated mid-marsh through the transition zone in Pt. Reyes National Seashore (50 km N of the estuary).…”

A stem-boring moth drives detritus production in SW Atlantic marshes

“…Mitsch & Gosselink 1993), and depending on their permeability (Stamps et al 1987, Lopez-Barrera et al 2007, they can regulate the flux of organic matter between habitats (e.g. nutrients, detritus and species; Mitsch & Gosselink 1993, Traut 2005. These charac-ABSTRACT: Boundary habitats are frequently hotspots for the production and flow of organic matter (OM) and exert strong effects on ecological processes in the habitats which they link.…”

“…Although boundary habitats share characteristics with neighbouring habitats, they also have their own unique characteristics that are defined by the strength of their interactions with their neighbour habitats (e.g. Holland 1988, Traut 2005. Boundary habitats are frequently production hotspots (e.g.…”