The influence of cryptogamic crusts on the thermal environment and temperature relations of plants in a high arctic polar desert, Devon Island, N.W.T., Canada

The thermal microenvironment and leaf temperatures of two plants (Saxifraga caespitosa and S. oppositifolia) were studied in a high arctic polar desert over four summers. Surface and plant temperatures exceeded air temperatures by 5 to 15°C during sunny periods, with smaller effects on soil temperature in plant rooting zones. Midday plant temperatures of 20 to 30°C measured during good weather are favorable for physiological activity, but the number of such days is restricted by a short snow-free period (16-45 d). Surfaces in polar deserts are dominated by sorted stones and bare mineral soil with sparse vascular plant cover (usually