Changes in properties of mangrove sediment due to foraging onKandelia obovataleaves by crabsParasesarmea plicatum(Grapsidae: Sesarminae)

Sesarmid crabs are important ecosystem engineers in mangroves because they remove a large proportion of mangrove leaf litter. However, the effects on mangrove sediments of sesarmid crab foraging on mangrove leaves has been poorly quantified. Through a laboratory experiment, the present study aimed t...

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Bibliographic Details
Published in:Marine ecology. Progress series (Halstenbek) 2010-11, Vol.419, p.137-145
Main Authors: Chen, Guang C., Ye, Yong
Format: Article
Language:English
Subjects:
Crabs
Ecosystems
Enzyme activity
Foraging
Leaves
Mangrove forests
Nitrogen
Nutrient retention
Phosphatases
Sediments
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Summary:Sesarmid crabs are important ecosystem engineers in mangroves because they remove a large proportion of mangrove leaf litter. However, the effects on mangrove sediments of sesarmid crab foraging on mangrove leaves has been poorly quantified. Through a laboratory experiment, the present study aimed to quantify changes in nutrient concentrations and enzyme activities in mangrove sediment due to foraging onKandelia obovataleaves byParasesarmea plicatumcrabs. Non-leaf foraging activity (i.e. the crabs were not fed with leaves) ofP. plicatumhad insignificant effects on the concentrations of sediment organic carbon (OC), total nitrogen (TN) and phosphate, but significantly increased sediment NO₃⁻-N concentration. Sediment urease activity was inhibited while invertase activity was enhanced by crab activity. Compared with non-leaf foraging, crabs fed withK. obovataleaves showed different effects on sediment properties. Leaf foraging by crabs significantly increased sediment OC and TN concentrations, and activities of enzymes except for invertase and urease. Significant correlations were found among sediment nutrient concentrations and enzyme activities. Foraging on 1.00 gK. obovataleaves byP. plicatumresulted in accumulations of 154.94 mg OC and 10.26 mg TN in sediment. Removing crab faecal material from the sediment reduced these effects of leaf foraging by crabs on sediment properties, but there was still significant accumulation of OC and TN in the sediment compared with the control. The present study demonstrated that foraging on mangrove leaves byP. plicatumplays an important role on nutrient retention in mangrove sediment and that crab faecal material mediates this ecological function.
ISSN:0171-8630
1616-1599