Restoring riparian meadows currently dominated by Artemisa using alternative state concepts ‐ above‐ground vegetation response

Abstract

Abstract. Livestock overgrazing and stream incision in the western USA often result in encroachment and dominance of Artemisia tridentata ssp. tridentata (Big sagebrush) in riparian areas that formerly supported meadows. To define the alternative states and thresholds for these ecosystems, we conducted a restoration experiment that included sites with high, intermediate or low water tables. We used a paired‐plot approach in which one plot on each site was burned and seeded with native grasses and forbs typical of naturally occurring dry meadow and Artemisia/Leymus cinereus ecological types, while adjacent unburned plots served as controls. Sites with high and intermediate water tables had greater initial abundances of perennial grasses typical of dry meadows, such as Leymus triticoides and Poa secunda ssp. juncifolia, and these species increased after the burn. In contrast, sites with low water tables were dominated by annual forbs such as Chenopo‐dium album and Descurainia pinnata after the burn. Biomass increased progressively from 1997 to 1999 on burned plots, while controls showed little change. Burning effects were microsite specific, with former Artemisia microsites exhibiting lower biomass than interspaces initially, but similar or higher biomass by the third year. Establishment of seeded species was low and species composition was determined largely by pre‐burn vegetation. Artemisia dominated sites with high water tables appear to represent an alternative state of the dry meadow ecological type, while sites with low water table sites have crossed an abiotic threshold governed by water tables and represent a new ecological type. Burning is an effective tool for restoring relatively high water table sites, but low water table sites will require burning and seeding with species adapted to more xeric conditions.

Climatic controls on sap flow dynamics and used water sources of Salix psammophila in a semi-arid environment in northwest China

“…Evaluating the ecosystem response to environmental fluctuations is crucial, among other things, to the management and restoration of plant communities (Wright and Chambers 2002;Ridolfi et al 2006). These processes depend on sap flow, which drives the physiological responses of desert plants, and sap flow depends on the plant's water balance and on subsurface hydrology (Lambs and Berthelot 2002).…”

A review of fire effects on vegetation and soils in the Great Basin Region: response and ecological site characteristics

“…native perennial grasses and forbs had low cover prior to treatment and invaders existed on the site Koniak 1985;Hosten and West 1994;Young and Miller 1985;Wright and Chambers 2002;Chambers and others 2007, in press;Miller and others in review). However, as illustrated in fig.…”

“…Annual forb cover usually increases in the first one to five years post-fire followed by a decline within three to five years ( fig. 29) (Barney and Frischknecht 1974;Everett and Ward 1984;Koniak 1985;Cook and others 1994;Wright and Chambers 2002;Dhaemers 2006;others 2007a, 2011;Davies and others 2007;Rhodes and others 2010;Miller and others in review). Bates and others (2007a) reported annual forb cover increased >3-fold in the first year following fire but dropped below pre-burn levels in the fifth post-fire year.…”

An eco-hydrological approach to predicting regional vegetation and groundwater response to ecological water conveyance in dryland riparian ecosystems

“…The understanding of the systems and their response to anthropogenic and natural disturbances are of foremost importance for management and restoration of these ecosystems (Wright and Chambers, 2002;Ridolfi et al, 2006). To understand such systems, integration of hydrology and ecology is needed, and a new interdisciplinary research focus called eco-hydrology has been created (Crawford, 2000;Zalewski, 2002;Hannah et al, 2004).…”