Lund easement baseline biological inventory

Abstract

This subset of the International Classification of Ecological Communities (ICEC) covers vegetation alliances and associations attributed to the Hill County, Montana. This community classification has been developed in consultation with many individuals and agencies and incorporates information from a variety of publications and other classifications. Appendix B Dynamics: Sarcobatus vermiculatus, like many facultative halophytes, is tolerant of alkaline and saline soil conditions that allow the species to occur in sites with less interspecific competition (Ungar et al. 1969, Branson et al. 1976). The shrub also occurs on extremely arid non-saline sites. Sarcobatus vermiculatus is often found on sites with high water tables that are intermittently flooded. Hansen et al. (1995) reported that it can tolerate saturated soil conditions for up to 40 days. Sarcobatus Appendix B 5 vermiculatus-dominated vegetation can occur as a narrow band along a channel, or in a mosaic of communities where composition and density of the shrub and understory species vary with depth to water table, salinity and alkalinity, soil texture, and past land use or disturbance. Hanson (1929) described stands in south-central Colorado and found that pure stands of Sarcobatus vermiculatus and Distichlis spicata are more common on strongly saline/alkaline sites with finetextured soil and shallow water tables, whereas stands with mixed shrubs such as Chrysothamnus or Artemisia are more common on drier, coarser textured, low-alkaline sites. Sporobolus airoides is found on dry, strongly alkaline sites, and Pascopyrum smithii is most common on less alkaline, moist, sites in low lying areas. Sarcobatus vermiculatus is not ordinarily browsed, but Daubenmire (1970) found that under heavy stocking rates, the shrubs will develop a compact canopy. Hansen et al. (1995) also reported browsing damage with heavy spring and summer grazing, but noted that Sarcobatus vermiculatus is moderately poisonous to livestock especially in the fall, and supplemental feed is recommended to avoid livestock loss. Hanson (1929) states that Sarcobatus vermiculatus can form an important part of winter forage for sheep. Fire will topkill Sarcobatus vermiculatus, but the shrub will promptly resprout from the root crown (Daubenmire 1970). NRCS range sites for the eastern plains of Colorado do not describe this alliance on good condition sites. Several range sites (Salt flat #33, Saline overflow #37) list Sarcobatus vermiculatus as present in low abundance in good condition stands but describe it as increasing with overgrazing. The NRCS range sites also describe Bouteloua gracilis increasing with overgrazing. Stands dominated by Sarcobatus vermiculatus with an understory dominated by Bouteloua gracilis been observed in eastern Colorado (S. Kettler pers. obs.).