Browsing-induced effects on leaf litter quality and decomposition in a southern african savanna

D. A. Fornara, J. T. Du Toit

    Research output: Contribution to journalArticle

    23 Citations (Scopus)

    Abstract

    We investigated the linkages between leaf litter quality and decomposability in a savanna plant community dominated by palatable-spinescent tree species. We measured: (1) leaf litter decomposability across five woody species that differ in leaf chemistry; (2) mass decomposition, nitrogen (N); and carbon (C) dynamics in leaf litter of a staple browse species (Acacia nigrescens) as well as (3) variation in litter composition across six sites that experienced very different histories of attack from large herbivores. All decomposition trials included litter bags filled with chopped straw to control for variation in site effects. We found a positive relationship between litter quality and decomposability, but we also found that Acacia and straw litter mass remaining did not significantly vary between heavily and lightly browsed sites. This is despite the fact that both the quality and composition of litter returned to the soil were significantly different across sites. We observed greater N resorption from senescing Acacia leaves at heavily browsed sites, which in turn contributed to increase the C:N ratio of leaf litter and caused greater litter N immobilization over time. This, together with the significantly lower tree- and herb-leaf litter mass beneath heavily browsed trees, should negatively affect decomposition rates. However, estimated dung and urine N deposition from both browsers and grazers was significantly greater at high- than at low-herbivory sites. We hypothesize that N inputs from dung and urine boost litter N mineralization and decomposition (especially following seasonal rainfall events), and thereby offset the effects of poor leaf litter quality at chronically browsed sites.
    LanguageEnglish
    Pages238-249
    JournalEcosystems
    Volume11
    Issue number2
    DOIs
    Publication statusPublished - Mar 2008

    Fingerprint

    browsing
    plant litter
    savannas
    degradation
    Acacia
    straw
    herbivores
    urine
    feces
    staples
    resorption
    carbon nitrogen ratio
    bags
    leaves
    herbs
    plant communities
    mineralization
    chemistry
    rain
    carbon

    Cite this

    Fornara, D. A. ; Du Toit, J. T. / Browsing-induced effects on leaf litter quality and decomposition in a southern african savanna. In: Ecosystems. 2008 ; Vol. 11, No. 2. pp. 238-249.
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    Browsing-induced effects on leaf litter quality and decomposition in a southern african savanna. / Fornara, D. A.; Du Toit, J. T.

    In: Ecosystems, Vol. 11, No. 2, 03.2008, p. 238-249.

    Research output: Contribution to journalArticle

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