The Nature and Restoration of Denuded Areas in Iceland

Abstract

Denuded areas in Iceland can be divided into the following categories: glacial deposits, sandy areas, postglacial lavas, alluvial and colluvial materials, and areas covered with pumice. Of these, glacial deposits are most extensive. The paper describes the nature of the denuded areas with emphasis on the glacial deposits. The denuded glacial deposits generally have sparse plant cover (< 5070) and suffer from wind abrasion and cryoturbation. The soils are deficient in organic matter (about 1%). The texture is sand and loamy sand. Despite the lack of organic materials and the coarse texture, the sum of exchangeable cations ranges from 5 to 15 meq 100 g-l dry soil. Revegetation with agronomic grasses and fertilization under subarctic conditions in the Ice-landic highlands has increased the vegetative cover to over 50% after 5 yr of fertilization. Little increase in soil organic matter is apparent after 5 yr. Objectives for revegetation in Iceland include (1) reclamation of disturbed areas; (2) stabilization of moving sand; (3) prevention of soil erosion; (4) forage production; (5) aesthetic reasons; and (6) restoration. Slow natural restoration is attributed to grazing, low temperatures , freeze-thaw cycles and needle ice, abrasion due to wind erosion, desiccation, lack of seed sources, low biological activity, low nutrient status, and leaching of nutrients.