Temperature Observations in High Arctic Plants in Relation to Microclimate in the Vegetation of Peary Land, North Greenland

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Abstract
Temperatures were recorded in Peary Land in and around the sparse vegetation in a number of microenvironments of differing snow cover, moisture, slope effect, insolation and plant species, during the summer of 1978. Temperature measurements of this kind have not previously been made so far north. Some of the results compare well with existing knowledge from other arctic investigations, whereas others appear to be previously unrecorded. Under sunny conditions plant temperatures are very high, often more than 20.degree. C above ambient air temperature. There is a marked diurnal temperature variation in plants and soil as well as in the air close to the ground and under the midnight sun. The variation is less pronounced 2 m above the ground and is almost absent with overcast sky. Slope has a pronounced effect on microclimate. On a 20.degree. north-facing slope the diurnal variation is opposite that of level ground and of that of south slopes. Inversion was observed only on a south-facing slope. The response of arctic plants to insolation differs between species. Dryas integrifolia, Saxifraga caespitosa, and S. oppositifolia, for example, attain much higher temperatures than other members of the high arctic flora. Organs with no obvious design for heat accumulation or heat conservation often show the highest temperatures. Most pronounced are the shoot apices of the species listed above. This heat generation may have a physiological rather than physical explanation.