Global change and precipitation redistribution: Effects on tree-grass ratios
- Univ. of Arizona, Tucson, AZ (United States)
Predicted shifts in precipitation seasonality (caused by global increases in atmospheric [CO{sub 2}]) may affect competitive interactions between grasses and woody plants, and ultimately affect their abundance and distribution. We are investigating the potential importance of 4 precipitation redistribution scenarios on woody plant/grass interactions at an oak woodland/semi-desert grassland ecotone in southeastern Arizona. Experimental soil volumes decoupled from ambient precipitation and soil moisture are hand-watered such that controls (C) receive the equivalent of mean annual precipitation (602mm) for the site, and treated plots receive all combinations of 50% additions and reductions of summer (S=JAS) and winter (W=DJF) precipitation. Plots contain extant stands of C{sub 4} bunchgrasses, into which we planted Emory oak (Quercus emoryi) acorns on 17 July 1994. Oak seedling emergence was complete by 30 September (end-of-summer), with means of 51, 20, and 61% in C, S{sub dry}, and S{sub wet} plots, respectively; corresponding survival of emerged seedlings was 91, 95, and 94%. End-of-summer herbaceous standing biomass was 167, 102, and 154 g/m{sup 2} in C, S{sub dry}, and S{sub wet} plots. Seedling survival on 14 January 1995 was 2-3% (absolute) lower than at end-of-summer, with the exception of S{sub wet}/W{sub dry} plots that experienced a 10% reduction in survival. Results to date suggest that Emory oak recruitment is directly linked to the quantity of monsoonal precipitation, and that climate change-induced shifts in seasonal soil moisture may affect tree-grass ratios.
- OSTI ID:
- 95904
- Report Number(s):
- CONF-9507129-; ISSN 0012-9623; TRN: 95:004728-0172
- Journal Information:
- Bulletin of the Ecological Society of America, Vol. 76, Issue 2; Conference: 80. anniversary of the transdisciplinary nature of ecology, Snowbird, UT (United States), 30 Jul - 3 Aug 1995; Other Information: PBD: Jun 1995
- Country of Publication:
- United States
- Language:
- English
Similar Records
Data from: "Warming and the dependence of limber pine (Pinus flexilis) establishment on summer soil moisture within and above its current elevation range"
Warming-Induced Biome Change at the Temperate-Boreal Ecotone: An Experimental Test of Key Regeneration Processes (Final Technical Report)