In the August 2005 feature article, “Tiff over Tamarisk: Can a Nuisance Be Nice, Too?” the author raises several issues about which there is currently scientific debate, and presents some of the differing perspectives. A phenomenon surrounding discussions of tamarisk in the West is revealed and reinforced in the article—the polarized nature of the debate. Over the years, this polarization has fueled acrimonious exchanges between scientists and led to confusion regarding the effects of tamarisk, thus hindering the ability of resource managers to formulate clear policies for managing this species. Unfortunately, the author has perpetuated the polarized nature of the tamarisk debate by labeling two camps—“revisionists” and “traditionalists.”
I suggest that instead of continuing to view those engaged in research on, or management of, tamarisk as falling into one camp or another, all participants recognize and seek to better understand the ecological complexity behind the issues. It is this complexity that enables those with different perspectives to find examples that support their “side.” Tamarisk grows across a huge geographic area, encompassing several ecoregions, along dynamic riparian lands managed by entities with different priorities. There are many instances where tamarisk invasion has been facilitated by stream-flow regulation, but there are others where tamarisk has invaded relatively pristine sites. Tamarisk's abundance and its associated effects on ecosystems vary greatly. Different wildlife taxa respond differently to tamarisk—some are unaffected or benefit, others do not thrive in tamarisk habitat. Tamarisk may use more or less water than other vegetation that might replace it. Scientists and resource managers should stay focused on seeking to better understand this complexity, so that they can best support the development of appropriate management strategies.
One key issue that I think was underreported in the article is that of restoration or revegetation associated with tamarisk control. The extent to which wildlife use or water use changes following tamarisk control depends largely on what vegetation replaces tamarisk. Thus, the feasibility and cost of producing and maintaining desired replacement vegetation deserve careful consideration before embarking on control efforts, not after, as is often the case.
Finally, I had asked that the word “mesic” be added to a comment attributed to me in the article so that it read, “Recent studies do not show that tamarisk consumes more water than mesic native species.” The scientific evidence does not clearly show that tamarisk uses more water than mesic (moist site) native riparian species such as cottonwood and willow. There is, however, evidence that tamarisk uses more water than many xeric (dry site) native species (e.g., some grasses and shrubs).