The Role of Equisetum in Nutrient Cycling in an Alaskan Shrub Wetland

Marsh, Anne; Arnone, John; Bormann, Bernard; Gordon, John

'1 Although plants of Equisetum spp. are generally thought to be of little value to ecosystems, a study of a cold-temperate Alaskan shrub wetland showed that they acquired and cycled phosphorus and other nutrients more efficiently than other plant community members. While Equisetum plants represented only 5% of the above- and below-ground biomass in the community, they contained 16% of the P and 24% of the K. 2 Equisetum plants accounted for 29% of the P and 39% of the K in annual community foliage litterfall. Over a 2-year period, losses from Equisetum litter contributed 55, 41, and 75% of the P, K and Ca litter inputs into soil nutrient pools. 3 The ability of different species of Equisetum to acquire nutrients is linked to their deep rooting habit. While the majority of their roots and rhizomes, and particularly the fine roots, were located in the C horizon, the majority of roots and rhizomes of other species were located in the overlying O horizon. The biomass of Equisetum plants was also correlated with edaphic characteristics of the C horizon. 4 The absorption of nutrients from the C horizon by Equisetum helped bring P and other minerals to the soil surface, increasing the amount of minerals in the O horizon and thus making them potentially available to other species, including Myrica gale, Salix spp., and Carex spp. Productivity in this community is limited by P and N, and the ability of Equisetum to act as a nutrient pump may help explain why its net primary productivity is high for a cold-temperate wetland.'

The Role of Equisetum in Nutrient Cycling in an Alaskan Shrub Wetland

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