Species richness, abundance, rarity and environmental gradients in coastal barren vegetation

Abstract

Coastal barrens in Nova Scotia are heathlands characterised by short, predominantly ericaceous vegetation, sparse tree cover, exposed bedrock, pockets of Sphagnum bog, and stressful climatic conditions. Although coastal barrens are prominent in the physical and cultural landscape, they are largely unprotected. We selected six barrens along the Atlantic coast, and surveyed 20 1-m 2 plots at each barren for vascular plants, macrolichens, mosses and environmental factors. We recorded 173 species (105 vascular, 41 macrolichen, 27 moss), including six provincially rare vascular species found predominantly in nearshore areas with high levels of substrate salt and nutrients, variable substrate depth, and short vegetation. Although vascular plant and moss richness were similarly correlated with vegetation height, substrate depth, organic matter content, and rock exposure, there were no clear correlations between vascular plant, macrolichen and moss richness across all sites. Vascular plant rarity and species richness were not correlated, but had inverse relationships with key environmental gradients. Tailoring conservation efforts to protect areas of high richness may thus mean that rare species are missed, and vice versa. Ordination and ANOSIM show that barrens vegetation differs widely among sites; therefore, protecting any singular coastal barren will not protect the entire range of vegetation communities and species in this heathland type. Conservation planning should emphasize protecting environmental gradients correlated with richness, rarity and plant community structure, including substrate depth and moisture, and vegetation height. Additionally, protected areas should include a coastal-inland gradient and a diversity of substrate types, including exposed rock and trees.

The effect of topsoil removal in restored heathland on soil fauna, topsoil microstructure, and cellulose decomposition: implications for ecosystem restoration

“…Heathland is a traditional habitat in Western Europe (De Smidt 1979;Webb 1998) and parts of Northern America (Oberndorfer and Lundholm 2009) with very characteristic plants and animals (Delettre et al 2008;Lin et al 2007;Maes et al 2003;Telfer and Eversham 1996). In most countries, the present area covered with this vegetation type is only a fraction of the area covered around 1900 (Härdtle et al 2009), and heathland is now considered an EU priority habitat for conservation.…”

Saxicolous Lichens on a Nova Scotian Coastal Barren

“…All lichens were sampled within 550 m of the shoreline, the same range distance to coast studied in previous research on coastal barrens in Nova Sco (Oberndorfer and Lundholm 2009), along three transects within the Chebuc Head wilderness area.…”

“…Research describing the composition of their vegetation has revealed a diverse array of vascular plants, mosses, and macrolichens in these "barren" habitats (Oberndorfer and Lundholm 2009). Lichens play an important role in coastal heathland ecosystems, often covering substantial areas (Chris tensen andJohnsen 2001, Oberndorfer andLundholm 2009). describing the gradient of lichen communit terrestrial region. However, large-scale p tion do show a maritime gradient (McCune are specific to coastal habitats (Brodo et Fletcher (1973a, b) provided an extensi pralittoral lichens in Great Britain.…”

Cladonia lichens on extensive green roofs: evapotranspiration, substrate temperature, and albedo

“…They can survive and grow on the bare surface of rocks and in poor soils such as heathlands, peat lands, sand dunes, and toxic spoil heaps 10 . Selection of vegetation types appropriate for extensive green roofs often involves identifying local habitats that have characteristics in common with green roofs (shallow soil, harsh abiotic conditions) 11 ; lichens are a common component of rock barrens, dunes, and heathland habitats that can be a source of plants for green roofing projects 12, 13 .…”