Community structure and leaf trait heterogeneity in a deciduous thicket community of the Middle Zambezi River Valley, Zambia

Deciduous Zambezi thicket forms a mixed-layered, dry woodland community on deep alluvial soils of the Middle Zambezi Valley. The dominant species are spiny, thicket-forming deciduous shrubs and small trees with no single dominant species and variable composition along the valley. A detailed community study of deciduous thicket along the Middle Zambezi River provided an indication of the wide variation of species-specific characteristics of growth form, phenology, and leaf traits that combine to produce a heterogeneous assemblage. Two families, the Capparaceae and Leguminosae, are particularly well represented. Leaf traits of nitrogen content, specific leaf area, δ13C, and δ15N are highly variable between species, with indications of some consistency in family traits within the Capparaceae and Leguminosae. A number of species exhibit a strong pattern of association with termite mounds, and termitaria are known to have significant potential impacts on spatial patterns of soil nutrient availability and water relations in savanna communities. There remains a poor understanding of the significance of symbiotic nitrogen fixation in deciduous African thicket, and savanna, and woodland communities and its importance in ecosystem fluxes of nitrogen, and these issues cannot be resolved by simple measurements of δ15N alone. Intraregional patterns of variation in leaf traits may impact the broad application of regional ecosystem models, as with those developed in the SAFARI 2000 program, when the variance between species is high, demonstrating that climatic controls on ecosystem δ15N abundance are scale‐dependent.