Relationships between water availability, carbon isotope discrimination and plant productivity in two semi-arid grass and shrub species

• Published in: Journal of arid environments Vol. 41; no. 1; pp. 49 - 60
• Main Author: LAUNDRE, J. W
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier Ltd 01.01.1999; Elsevier
• Subjects: Agricultural and forest climatology and meteorology. Irrigation. Drainage; Agricultural and forest meteorology; Agronomy. Soil science and plant productions; Agropyron smithii; Animal and plant ecology; Animal, plant and microbial ecology; Artemisia tridentata; Autoecology; Biological and medical sciences; cool desert; Fundamental and applied biological sciences. Psychology; General agronomy. Plant production; Plants and fungi; sagebrush; south-east Idaho; Water balance and requirements. Evapotranspiration; western wheatgrass; United States; North America; Idaho; America; cool desert; sagebrush; western wheatgrass; south-east Idaho; Monocotyledones; Carbon isotope discrimination; Fodder shrub; Water supply; Agropyron smithii; Compositae; Biological productivity; Artemisia tridentata; Gramineae; Semi arid zone; Dicotyledones; Angiospermae; Spermatophyta; Fodder crop; Desert
• ISSN: 0140-1963; 1095-922X
• DOI: 10.1006/jare.1998.0469

The positive relationship between water availability and carbon isotope discrimination (Δ) is well documented. There is also evidence that Δ is positively related to plant productivity. However, most of the data are concerned with cross species and genotypic variation in Δ relative to broad geographical differences in water availability or on general trends in local populations. We still lack quantified data on the response of localized populations to changing water availability, carbon isotope discrimination (Δ) and plant productivity, especially on a year to year basis. To provide data in this area, this study measured above-ground productivity in western wheatgrass (Agropyron smithii) and vegetative stem growth in big sagebrush (Artemisia tridentata), and carbon isotope discrimination in both species over several years of varying water availability. Estimates of Δ were regressed against spring soil moisture estimates, and plant productivity measure ments against Δ estimates. For sagebrush, carbon isotope discrimination estimates were positively related to spring soil moisture levels (p=0.027,r2=0.11) and productivity estimates (p=0.002,r2=0.23). Carbon isotope discrimination for wheatgrass also regressed significantly with soil moisture levels (p=0.039,r2=0.10) and productivity estimates (p< 0.001,r2=0.33).