Variation in creosotebush (Larrea tridentata) canopy morphology in relation to habitat, soil fertility and associated annual plant communities

• Published in: The American midland naturalist Vol. 137; no. 1; pp. 13 - 26
• Main Authors: De Soyza, A.G. (USDA, ARS, Jornada Experimental Range, Las Cruces, NM.), Whitford, W.G, Martinez-Meza, E, Van Zee, J.W
• Format: Journal Article
• Language: English
• Published: Notre Dame University of Notre Dame 01.01.1997; University of Notre Dame, Department of Biological Sciences; American Midland Naturalist
• Subjects: ANATOMIA DE LA PLANTA; ANATOMIE VEGETALE; Botany; CALIFORNIA; CALIFORNIE; Creosote bush; Desert soils; Deserts; Flowers & plants; Larrea tridentata; Morphology; NEVADA; NEW MEXICO; Nitrogen; NOUVEAU MEXIQUE; NUEVO MEXICO; PLANT ANATOMY; Plant communities; Plant morphology; Plants; Shrubs; Soil morphology; Soil nutrients; Soils; Stems; Vegetation canopies; Water; XEROFITAS; XEROPHYTE; XEROPHYTES; USA, Southwest
• ISSN: 0003-0031; 1938-4238
• DOI: 10.2307/2426751

Differences in creosotebush (Larrea tridentata) crown morphology may reflect changes in the relative demand for water vs. nutrient resources, coinciding with shrub growth and development. Creosotebushes with inverted cone-shaped crowns were more abundant in water-limited environments whereas hemispherical shaped creosotebushes were more abundant in less water-limited environments. Cone-shaped creosotebushes accumulated substantially less litter under their canopies than did creosotebushes with hemispherical shaped crowns. Soil nutrient concentrations under conical shrubs were similar to those in intershrub spaces and both of these were significantly less than soil nutrient concentrations under hemispherical shrubs. In ecosystems where overland flow of water exerted a greater influence on the movement of organic litter than did wind, shrub shape had little effect on long-term litter accumulation. No persistent differences in the biomass or diversity of ephemeral taxa exploiting undershrub areas were found, probably because the positive effects of greater nutrient resources under hemispherical shrubs were offset by the limitations imposed by the larger, more dense canopies of hemispherical shrubs. Overall, creosotebush morphology affected litter accumulation patterns and soil nutrient patterns, and must be considered when assessing the heterogeneity of desert ecosystems in the southwestern USA.