Document: JEA-3-64-10

Restoring dry meadow ecosystems using threshold and alternative state concepts: Environmental and seedling response.

CHAMBERS, J.C.* ¹, A.R.LINNEROOTH ² and P.S.MEBINE ²

USDA Forest Service, Reno, NV 89512 USA ¹
University of Nevada, Reno, Reno, NV 89512 USA ²

Abstract:
Degradation of riparian corridors due to livestock overgrazing and stream incision in the western US has resulted in the encroachment of a native perennial shrub, Artemisia tridentata. The potential for restoration to former meadow systems may still exist where an environmental threshold determined by water table levels has not been crossed. We used two environmentally similar ecosystem types that appear to exist as alternative states, the dry meadow and A. tridentata/Elymus cinereus trough drainageways, as models for examining the potential restoration of sagebrush dominated sites to dry meadows. The restoration treatment included three water table levels and involved a paired-plot approach in which half of the plot was burned and seeded with native grasses characteristic of the dry meadow and half served as a control. Burning resulted in higher soil temperatures, especially in undershrub environments, higher levels of extractable nutrients, and higher soil water availability at deeper depths. Sites with high water tables had lower soil temperatures and higher soil water availability. In these semi-arid ecosystems, seedling emergence was highest on sites with high water tables, during a wet year, and for species adapted to drier conditions. More favorable environmental conditions and establishment of dry meadow species indicate that sites with high water tables have not crossed a threshold and can be restored to dry meadows. Our research indicates that alternative states exist on the landscape and that the thresholds between them can be defined based on abiotic and biotic variables. This information can be used to determine restoration protocols.

Keywords: Restoration, riparian, _Artemisia tridentata_, seedling establishment

This abstract is being presented at: 10:30 AM in session:
RESTORATION ECOLOGY AND INVASIONS