Climate change in the Mojave Desert (USA) may result in a greater intensity of summer (monsoon) rain events and greater atmospheric N deposition. Patches of the dominant biological crust moss Syntrichia caninervis were exposed to field treatments of low and high nitrogen supplementation, added summer rain, and combinations thereof, for a period of five years. In the lab, shoots were subjected to a moderate (single rapid-dry treatment) and a severe (double rapid-dry treatment) desiccation stress. Shoots were then hydrated and allowed to regenerate for 6 weeks on sterile sand. Shoots exhibited lower aboveground biomass from the +monsoon treatment, indicating carbon balance deficits under conditions of recurring summer rainfall. The low N treatment and the severe desiccation stress promoted shoot burning (chlorosis) and negatively affected regeneration responses. High N treatment, however, only adversely affected the resumption of apical meristematic growth. Summer irrigation and N application interacted to mitigate the effects of later protonemal emergence time, lower protonemal cover, and lower shoot numbers. Increased monsoonal frequency and higher N deposition as forecast for the northern Mojave Desert may result in declines in shoot biomass and reduced regenerational vigor in S. caninervis.
|Number of pages||7|
|Journal||Journal of Arid Environments|
|State||Published - May 2011|
Bibliographical noteFunding Information:
We thank Lorenzo Nichols II for assistance in the laboratory, Lynn Fenstermaker, Dene Charlet, and Jon Titus for installing the initial field site treatments, and Eric Knight and Derek Babcock for providing field assistance and managing site operations. This research was supported by the Office of Science, Biological and Environmental Research Program (BER), U.S. Department of Energy (DOE), through the Western Regional Center of the National Institute for Climate Change Research (formerly known as Nat. Inst. for Global Environmental Change) under Cooperative Agreement No. DE-FCO2-03ER63613. Financial support does not constitute an endorsement by DOE of the views expressed in this article. DNM was supported by NSF grant IOB 0416407. LRS was supported by a UNLV faculty sabbatical leave during a portion of this project.
- Biological soil crust
- Desiccation tolerance
- N deposition
ASJC Scopus subject areas
- Ecology, Evolution, Behavior and Systematics
- Earth-Surface Processes