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Titolo:
Experimental manipulations of precipitation seasonality: Effects on oak (Quercus) seedling demography and physiology
Autore:
Weltzin, JF; Snyder, KA; Williams, DG;
Indirizzi:
Univ Arizona, Sch Renewable Nat Resources, Tucson, AZ 85721 USA Univ Arizona Tucson AZ USA 85721 able Nat Resources, Tucson, AZ 85721 USA
Titolo Testata:
WESTERN NORTH AMERICAN NATURALIST
fascicolo: 4, volume: 61, anno: 2001,
pagine: 463 - 472
SICI:
1527-0904(200110)61:4<463:EMOPSE>2.0.ZU;2-6
Fonte:
ISI
Lingua:
ENG
Soggetto:
CARBON ISOTOPE DISCRIMINATION; TEMPERATE SAVANNA ECOTONES; HERBACEOUS VEGETATION; CLIMATIC-CHANGE; GAS-EXCHANGE; WATER-UPTAKE; RESPONSES; EMORYI; PLANTS; BIOGEOGRAPHY;
Keywords:
Quercus emoryi; precipitation seasonality; seedling recruitment; population demographics; carbon isotope discrimination; leaf gas exchange;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Agriculture,Biology & Environmental Sciences
Citazioni:
59
Recensione:
Indirizzi per estratti:
Indirizzo: Weltzin, JF Univ Tennessee, Dept Ecol & Evolutionary Biol, 569 Dabney Hall, Knoxville,TN 37996 USA Univ Tennessee 569 Dabney Hall Knoxville TN USA 37996 7996 USA
Citazione:
J.F. Weltzin et al., "Experimental manipulations of precipitation seasonality: Effects on oak (Quercus) seedling demography and physiology", WEST N AM N, 61(4), 2001, pp. 463-472

Abstract

Predicted changes in regional precipitation patterns and soil moisture caused by anthropogenic trace gas emissions may affect the distribution and abundance of woody plants in and and semiarid regions. To test the response of woody plants to potential changes in precipitation regimes, we manipulated summer and winter precipitation on plots that contained seedlings of Quercus emoryi Torn (Emory oak), the dominant tree in oak savannas of the southwestern United States. Throughout the growing season, we monitored seedlingsurvival and physiology (predawn leaf water potential, midday instantaneous gas exchange, and leaf carbon isotope discrimination). Seedling survival and physiological performance differed little between treatments, which embodied 50% changes to quantities of summer and winter precipitation, and encompassed a continuum of precipitation from 359 mm (.) year(-1) to 846 mm (.) year(-1). However, survival and physiological performance of seedlings were negatively impacted by seasonal environmental conditions common to all treatments, especially during the annual pre-'monsoon' drought. Seedling predawn leaf water potentials, net CO2 assimilation, and stomatal conductance indicate that growing conditions for Q. emoryi seedlings at this site are generally restricted to periods with adequate soil moisture (i.e., April andAugust). Results contrast with an assumption implicit to the "two-layer" soil water resource partitioning hypothesis that woody plants in all life history stages are more dependent upon winter than summer precipitation. In fact, summer precipitation appears more important than winter precipitation for Q. emoryi seedling recruitment and grow-th.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 29/03/20 alle ore 17:29:37