Association of Plant Distribution Patterns and Microenvironments on Patterned Ground in a Polar Desert, Devon Island, N.W.T., Canada

Abstract

In this study, we quantify the distribution patterns of vascular plant species among microsites (stony border, transition, and center) of sorted stone nets and stripes. We also monitored edaphic factors (frost heave, temperature, moisture, and texture) at three intensive sites to identify controls on plant distribution. Adult plants were more abundant in the transition microsite (73 and 77%) with its cryptogamic crust than random distribution would predict (transition cover 17 and 14%) at the noncrusted stone nets and stone stripes, respectively. Adult plants were frost heaved (10 and 32%) from the bare-soil center microsites at both sites. Nearly all of the few seedlings were in the transition microsite. At the crusted stone net, three species were randomly distributed; five species were over-represented in the two border microsites and two species were underrepresented there. No plants were frost heaved at this site and seedlings were abundant. There were 7.3 plants per lineal meter at the crusted net and only 3.0 and 2.3 plants per lineal meter at the noncrusted stone stripes and stone nets respectively. Of the environmental factors measured, soil heave (measured as soil settlement) appears most influential. Surface soils (0-1 cm) dry between summer rains and this may inhibit seedling establishment some summers. Soils at depth (5-10 cm) remain near saturation. Soil temperatures differed little between microsites