The roles of climate and soil nutrients in shaping the life histories of grasses native to the Cape Floristic Region

• Published in: Plant and soil Vol. 355; no. 1/2; pp. 323 - 340
• Main Authors: Verboom, G. Anthony, Moore, Timothy E., Hoffmann, Vera, Cramer, Michael D.
• Format: Journal Article
• Language: English
• Published: Dordrecht Springer 01-06-2012; Springer Netherlands; Springer Nature B.V
• Subjects: Agronomy. Soil science and plant productions; Animal, plant and microbial ecology; Annuals; Aquatic plants; Biological and medical sciences; Biomass; Biomedical and Life Sciences; Botanical research; Climate; Data processing; Ecological life histories; Ecology; Ehrharta calycina; Environment; Environmental aspects; Evolution; Flora; Fundamental and applied biological sciences. Psychology; General agronomy. Plant production; Grasses; Inflorescences; Joints; Life history; Life Sciences; Mountains; Nutrients; Plant growth; Plant Physiology; Plant Sciences; Plant-soil relationships; Plants; Poaceae; Rainy season; Regular Article; Rhizomes; Sand; Soil; Soil fertility; Soil nutrients; Soil plant interactions; Soil science; Soil Science & Conservation; Soil water; Soil-plant relationships. Soil fertility; Soil-plant relationships. Soil fertility. Fertilization. Amendments; Substrates; Survival; Southern Africa; Sub-Saharan Africa; Africa; Australia; Root mass ratio; Cape floristic region; Annual; Fynbos; Perennial; Relative growth rate; Rainfall; Flowering; Soil nutrients; Poaceae; Biomass allocation; Succulent karoo; Monocotyledones; Climate; Phytogeography; Growth rate; Biogeography; Physical environment; Biomass; Inorganic element; Rain; Gramineae; Angiospermae; Shrubbery; Partition; Life history; Meteorological phenomenon; Root; Mediterranean vegetation; Fynbos (sclerophyll shrubland); Soils; Vegetation type; Flora; Vegetative apparatus; Spermatophyta; Atmospheric precipitation
• ISSN: 0032-079X; 1573-5036
• DOI: 10.1007/s11104-011-1102-6

Aims We hypothesized that in seasonally-arid systems the evolution of annuality is controlled by both moisture regime and substrate quality, with infertile soils either precluding annuality or selecting for improved nutrient acquisition in annuals. The grass flora of the Cape Floristic Region to test these ideas. Methods We compared intrinsic variation in life history and nutrient acquisition traits between populations of Ehrharta calycina J. E. Sm. (Poaceae) situated along an aridity gradient and on diverse substrates. We also evaluated the importance of moisture regime and substrate as predictors of life history across 79 Cape grass species. Results In E. calycina, rhizome survivorship, plant growth and reproductive maturation rate were interrelated and closely tied to wet season duration. By contrast, life history variation was poorly correlated with soil nutrients, and there was little evidence of enhanced nutrient acquisition in annual populations. Across multiple species, however, substrate was identified as a significant co-predictor of life history. Conclusion Our identification of substrate as an important predictor of life history across multiple species but not within E. calycina is not paradoxical, since E. calycina consistently acts as an annual species in avoiding the ultra-oligotrophic, quartzitic sands that dominate the Cape mountains. Overall, our data support the joint influence of climate and substrate on the evolution of annuality and associated life history traits.