Decomposition of Chaparral Shrub Foliage: Losses of Organic and Inorganic Constituents from Deciduous and Evergreen Leaves
1981; Wiley; Volume: 62; Issue: 3 Linguagem: Inglês
10.2307/1937744
ISSN1939-9170
AutoresWilliam H. Schlesinger, Mavis M. Hasey,
Tópico(s)Botany, Ecology, and Taxonomy Studies
ResumoLitterbag methods were used to study the decomposition of leaves from an evergreen sclerophyll shrub, Ceanothus megacarpus, and a deciduous shrub, Salvia mellifera, in the chaparral of southern California. Initial concentrations of nitrogen were similar in the abscised leaves of both species, but abscised leaves of the evergreen species had higher concentrations of lignin. Over a 1—yr period, leaf litter of C. megacarpus lost 15 and 19% of its original ash—free dry mass at sites at 910 and 350 m elevation, respectively. Comparable losses for S. mellifera were 20 and 24%, respectively. Among the leaf constituents, the losses of soluble carbohydrates, phenolics and potassium in 1 yr were all >70% of original content for both species. Losses of calcium, magnesium and cellulose were smaller and there was no apparent release of nitrogen or decomposition of lignin. For these species the content of lignin or phosphorus appears to determine decomposition rates more than does the C/N ratio. Evergreen sclerophyll shrubs such as C. megacarpus are predominant over large areas of California chaparral. Despite relatively high lignin content in leaf litter, the mean residence time for organic matter on the soil surface was 4.6 yr for this species. Decomposition of leaf litter during the interval between natural fires may be a substantial source of plant nutrients for chaparral growth.
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