Hanuise, Douchan, Lin, Chieh, Tol, Samantha, Choukroun, Severine, Rasheed, Michael A., Dobbelaere, Thomas, York, Paul H., Smith, Timothy M., Coles, Robert G., Hanert, Emmanuel, and Grech, Alana (2026) Experimentally derived buoyancy duration of seagrass fragments for biophysical dispersal modelling in the Great Barrier Reef. Marine Environmental Research, 217. 107937.

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Abstract

The re-establishment of seagrass meadows following dieback events depends on the availability of viable propagules, particularly vegetative fragments that facilitate recovery beyond the local meadow through long-distance dispersal. The dispersal of vegetative fragments by ocean currents, waves and wind can be predicted by biophysical models. Among the model parameters, the duration of fragment buoyancy is an important determinant of dispersal but remains poorly quantified for tropical seagrass species. Yet, few empirical studies have assessed fragment dispersal traits and only for a small number of seagrass taxa. This limitation is particularly pronounced in tropical ecosystems, including the Great Barrier Reef (GBR), Australia, where tropical species exhibit diverse life histories and form extensive mixed-species meadows. This study aims to improve the accuracy of biophysical dispersal models for tropical seagrass by generating robust, species-specific data. We quantified the buoyancy duration of fragments from three species—Halophila ovalis, Halodule uninervis, and Zostera muelleri—over 48 days, and assessed whether initial morphological traits influenced buoyancy, finding species type was the primary determinant rather than fragment size. We then incorporated these empirical estimates into a biophysical model to evaluate their effects on dispersal. Our results highlight major differences between species. Z. muelleri floated the longest (24.7 3.0 days); H. uninervis sank the fastest; and H. ovalis was intermediate, generating broken fragments available for further dispersal. Integrating these experimental derived buoyancy values into a biophysical model reduced the mean predicted dispersal distances by 44% on average compared to previous models. These findings highlight interspecific dispersal behaviours and provide useable empirical data to refine future modelling studies. Such improvements are essential for predicting seagrass recovery, guiding restoration site selection, and informing management strategies that maintain connectivity and ecosystem resilience.

Item ID:	90833
Item Type:	Article (Research - C1)
ISSN:	1879-0291
Copyright Information:	© 2026 The Authors. Published by Elsevier Ltd. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/)
Funders:	Australian Research Council (ARC)
Projects and Grants:	ARC LP210300851
Date Deposited:	14 Apr 2026 01:34
FoR Codes:	31 BIOLOGICAL SCIENCES > 3103 Ecology > 310305 Marine and estuarine ecology (incl. marine ichthyology) @ 40% 41 ENVIRONMENTAL SCIENCES > 4102 Ecological applications > 410206 Landscape ecology @ 30% 37 EARTH SCIENCES > 3708 Oceanography > 370801 Biological oceanography @ 30%
SEO Codes:	18 ENVIRONMENTAL MANAGEMENT > 1805 Marine systems and management > 180507 Rehabilitation or conservation of marine environments @ 60% 18 ENVIRONMENTAL MANAGEMENT > 1805 Marine systems and management > 180501 Assessment and management of benthic marine ecosystems @ 40%
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