Publication

Unintended consequences: Tamarisk control and increasing threats to the southwestern willow flycatcher

Date: 2018/01/01

Author(s): McLeod, M.A.

Publication: In: Johnson, R. Roy; Carothers, Steven W.; Finch, Deborah M.; Kingsley, Kenneth J.; Stanley, John T., tech. eds. 2018. Riparian research and management: Past, present, future: Volume 1. Gen. Tech. Rep. RMRS-GTR-377. Fort Collins, CO: U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station. p. 62-84

URL: http://doi.org/10.2737/RMRS-GTR-377-CHAP5

DOI: 10.2737/RMRS-GTR-377-CHAP5

Abstract:

It is well known that nonnative tamarisk (Tamarix parviflora, T. ramosissima, T. chinensis, and their hybrids; a.k.a. saltcedar) has replaced native riparian woodland vegetation along many streams in the arid Southwest over the last 100 years. Tamarisk can form extensive, dense monocultures and may alter not only the physical structure of the riparian woodland but also soil salinity and fire frequency (Sher 2013). There is significant debate, however, over whether tamarisk is the driver or a passenger of ecological change (Johnson 2013). The decline in the numbers and range of native riparian wildlife has been concurrent with the spread of tamarisk, and numerous studies show that tamarisk-dominated stands may support a lower density and/or diversity of wildlife than do native habitats (Bateman and Ostoja 2012; Sogge et al. 2008; Strudley and Dalin 2013). Consequently, tamarisk is often portrayed as the primary cause for declines in riparian wildlife (e.g., DeLoach et al. 2003a). Although it is now recognized that water use by native vegetation compared to tamarisk depends on site conditions (Zavaleta 2013), tamarisk was also widely blamed for water consumption in excess of native species (Nagler and Glenn 2013). Tamarisk control efforts, many of which were driven by the desire to make more water available for human use, began in the 1940s (Douglass et al. 2013) and continue to the present day, with improvement of wildlife habitat often cited as a goal of tamarisk removal.