Snowbeds trapping seed rain - a comparison of methods

The possibility of assessing seed rain by deposits in snowbeds was investigated in the Abisko area in northernmost Swedish Lapland. In late summer the "grey blanket" on the snowbed surface was skimmed off, melted and sieved through a filter paper. The debris contained on average 741 seeds m(-2), making up 6.5% of the total debris dry mass. A total of 11,909 seeds, representing 69 species, were encountered in the study. Phyllodoce cocridea, Carex bigelowii and Juncus trifidus were the most abundant. The efficiency of the snowbeds as diaspore traps was compared with a set of artificial traps. Data from two years were compared. The snowbed proved to be more efficient than artificial seed traps, in particular for trapping seeds of graminoids and herbs. Both methods revealed considerable among-year variation in seed output as a possible result of differences in summer climate. The results also suggest that snowbed can be used for assessing aeolian inorganic deposition, in the present study on average 9.0 g m(-2).