Alaska research natural areas: 3. Serpentine slide.

Abstract

The 1730-ha Serpentine Slide Research Natural Area (RNA) is located in central Alaska in the White Mountains National Recreation Area. It is managed by the U.S. Department of the Interior, Bureau of Land Management, Steese-White Mountains District. Serpentine Slide was selected as a Research Natural Area (RNA) because it contains an alpine exposure of serpentinite; a 9-ha natural earth flow that has destroyed most vegetation in its path; bottom-land white spruce and balsam poplar forests growing on coarse gravels and sands of a major clearwater river flood plain; and warm, dry hill prairies on steep south-facing slopes. The area also contains several beaver dams, lodges, and ponds. Beaver-created habitats support typical wetland species including ducks and the northern wood frog. Open gravel bars and the high-quality, clear water of Beaver Creek provide nesting and breeding habitat for shore birds, especially the semipalmated plover. The Beaver Creek bottom-land corridor is a locally important habitat for grizzly bear, which use the RNA intensively in particular seasons. The variety of natural features of geologic, hydrologic, botanic, aquatic, and wildlife interest and the opportunity to monitor natural change in a locally diverse environment make Serpentine Slide RNA an outstanding scientific and educational resource.Concentric zones around serpentinite exposures in the RNA show increasingly toxic effects on plants. A widespread alpine plant in Alaska, Bupleurum triradiatum, is the vascular species most tolerant of serpentinite, but no special serpentine-adapted plant species have been discovered in the RNA. The center of serpentinite exposures in the RNA is naturally devoid of all plant life except an orange crustose lichen.The earth flow has been periodically active since at least the early 1950s. Dolomite and limestone are exposed on the lower slopes in the northeast portion of the RNA. The banks and overflow channels of Beaver Creek are made up of large to mediumsized smooth, rounded gravels with little fine sediments. The flood plain and terraces along the Beaver Creek portion of the RNA are generally made up of gravels and coarse sand, in contrast to the fine silts, sands, and clays of terraces and flood plains along typical northern Alaska rivers that carry glacial sediments.Belted kingfishers excavate nesting burrows in exposed river cutbanks along Beaver Creek. Goshawks use extensive stands of mature and old-growth white spruce forest and adjacent successional and wetland habitats.Three plants collected in the RNA, Carex eburnea, Artemisia alaskana, and Agropyron spicatum, are growing beyond their previously reported distribution in Alaska. A 150-year-old flood-plain white spruce forest supports about 40 m2/ha live tree basal area and contains dominant trees from 30 to 45 cm in diameter at breast height (d.b.h.) and up to 30 m tall. An upper elevation, south-slope white spruce forest supported 36 m2/ha, dominant trees 20 to 36 cm d.b.h. and a maximum of 19 rn tall.