Nitrogen addition increases fecundity in the desert shrub Sarcobatus vermiculatus

• Published in: Oecologia Vol. 143; no. 3; pp. 349 - 356
• Main Authors: Drenovsky, R.E, Richards, J.H
• Format: Journal Article
• Language: English
• Published: Berlin Springer 01.04.2005; Springer Nature B.V
• Subjects: Analysis of Variance; Animal and plant ecology; Animal, plant and microbial ecology; Biological and medical sciences; Calcium - metabolism; California; Community composition; Desert Climate; Desert soils; Deserts; Dunes; ecological succession; Ecophysiology; Fecundity; Fertility - physiology; Fertilizers; Fundamental and applied biological sciences. Psychology; General aspects; Leaves; Magnesium - metabolism; Magnoliopsida - drug effects; Magnoliopsida - growth & development; Magnoliopsida - physiology; Micronutrients; Nitrogen; Nitrogen - metabolism; Nitrogen - pharmacology; nitrogen content; nitrogen fertilizers; Nutrients; Phosphorus - metabolism; Plant communities; plant growth; Plant Leaves - metabolism; Plant nutrition; Plants; Sandy soils; Sarcobatus vermiculatus; Seed production; seed productivity; Seedlings; Seeds; Seeds - drug effects; Seeds - growth & development; Shrubs; Soil nutrients; xerophytes; Demography; Production quality; Leaf nutrient concentration; Fertilization; Seed production; Shrub; Fertilization experiment; Nitrogen; Medium enrichment; Reproduction; Black greasewood; Nutrient; Seed production and quality; Desert; Fecundity; Fitness
• ISSN: 0029-8549; 1432-1939
• DOI: 10.1007/s00442-004-1821-y

Nutrients, in addition to water, limit desert primary productivity, but nutrient limitations to fecundity and seed quality in desert ecosystems have received little attention. Reduced seed production and quality may affect recruitment, population, and community processes. At the Mono Basin, CA, USA where the alkaline, sandy soil has very low availability of N, P, and most other nutrients, seed production, recruitment, and dominance of the desert shrub Sarcobatus vermiculatus decrease over a dune successional sequence. Concurrently, Sarcobatus leaf N, P, and Ca/Mg ratio decline from early to later successional dunes. At two later successional dune sites, we fertilized adult Sarcobatus shrubs for 2 years and determined which nutrient(s) limited growth, seed production, and seed quality. We also tested whether nutrient addition at these older sites made these fitness-related variables equivalent to a younger, high-fecundity site. Nitrogen addition, alone, increased Sarcobatus leaf N, growth, and seed production per shoot module. Any treatment including P, Ca, Mg, or micronutrients but not N had an insignificant effect on growth and fecundity. Nitrogen addition also increased filled seed weight, a predictor of potential seedling survival, at one of the sites. Nitrogen-limited seed production and seed mass may reduce Sarcobatus fitness and contribute to the observed successional changes in plant community composition in this alkaline desert ecosystem.