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| Titel |
Modelling drivers of mangrove propagule dispersal and restoration of abandoned shrimp farms |
| VerfasserIn |
D. Nitto, P. L. A. Erftemeijer, J. K. L. Beek, F. Dahdouh-Guebas, L. Higazi, K. Quisthoudt, L. P. Jayatissa, N. Koedam |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1726-4170
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| Digitales Dokument |
URL |
| Erschienen |
In: Biogeosciences ; 10, no. 7 ; Nr. 10, no. 7 (2013-07-26), S.5095-5113 |
| Datensatznummer |
250018364
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| Publikation (Nr.) |
 copernicus.org/bg-10-5095-2013.pdf |
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| Zusammenfassung |
| Propagule dispersal of four mangrove species Rhizophora mucronata, R. apiculata, Ceriops tagal and Avicennia officinalis in the Pambala–Chilaw
Lagoon Complex (Sri Lanka) was studied by combining a hydrodynamic model
with species-specific knowledge on propagule dispersal behaviour. Propagule
transport was simulated using a finite-volume advection-diffusion model to
investigate the effect of dispersal vectors (tidal flow, freshwater
discharge and wind), trapping agents (retention by vegetation) and seed
characteristics (buoyancy) on propagule dispersal patterns. Sensitivity
analysis showed that smaller propagules, like the oval-shaped propagules of
Avicennia officinalis, dispersed over larger distances and were most sensitive to changing values
of retention by mangrove vegetation compared to larger, torpedo-shaped
propagules of Rhizophora spp. and C. tagal. Directional propagule dispersal in this
semi-enclosed lagoon with a small tidal range was strongly concentrated
towards the edges of the lagoon and channels. Short distance dispersal
appeared to be the main dispersal strategy for all four studied species,
with most of the propagules being retained within the vegetation. Only a
small proportion (max. 5%) of propagules left the lagoon through a
channel connecting the lagoon with the open sea. Wind significantly
influenced dispersal distance and direction once propagules entered the
lagoon or adjacent channels. Implications of these findings for mangrove
restoration were tested by simulating partial removal in the model of dikes
around abandoned shrimp ponds to restore tidal hydrology and facilitate
natural recolonisation by mangroves. The specific location of dike removal,
(with respect to the vicinity of mangroves and independently suitable
hydrodynamic flows), was found to significantly affect the resultant
quantities and species of inflowing propagules and hence the potential
effectiveness of natural regeneration. These results demonstrate the value
of propagule dispersal modelling in guiding hydrological restoration efforts
that aim to facilitate natural mangrove regeneration. |
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