Spatial and temporal variability of green turtle and dugong herbivory in seagrass meadows of the southern Great Barrier Reef (GBR)

Scott, Abigail L., York, Paul H., Macreadie, Peter I., and Rasheed, Michael A. (2021) Spatial and temporal variability of green turtle and dugong herbivory in seagrass meadows of the southern Great Barrier Reef (GBR). Marine Ecology Progress Series, 667. pp. 225-231.

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View at Publisher Website: https://doi.org/10.3354/meps13703
 
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Abstract

Megaherbivore grazing (e.g. by turtles, and sirenians) plays a major and well-documented role in structuring seagrass meadows around the world; however, we know little about local-scale (intra- and inter-meadow) variability in megaherbivore grazing. This is surprising given that megaherbivores are highly selective eaters who may feed by targeting certain meadows, or areas within a meadow. We ran an experiment in the Great Barrier Reef to test the question: How does megaherbivory vary on a regional scale? We used megaherbivore exclusion cages in 5 meadows along a 50 km region of coastline around Gladstone in the southern Great Barrier Reef World Heritage Area to understand variability in megaherbivory between meadows. We found differences in the impacts of megaherbivore grazing on seagrass biomass and shoot heights between meadows. There were also interannual differences in grazing impacts at one meadow that had been studied previously. These differences may be due to megaherbivore population and grazing dynamics, as well as the response of seagrass to grazing pressure. Our results show that seagrass meadows grazed by megaherbivores are dynamic systems that vary on regional spatial scales as well as over time. This is important for management measures that seek to consider the seagrass-herbivore system as a whole and understand the implications of monitoring efforts based on seagrass aboveground condition.

Item ID: 67577
Item Type: Article (Research - C1)
ISSN: 1616-1599
Keywords: Megaherbivore; Chelonia mydas; Dugong dugon; Grazing; Subtropical; seagrass ecosystems; Plant−herbivore interactions; Food web
Copyright Information: © Inter-Research 2021
Funders: Australian Research Council (ARC), Gladstone Ports Corporation Limited (GPC), Holsworth Wildlife Research Endowment (HWRE), National Environment Science Program (NESP) Tropical Water Quality Hub, Australian Government Research Training Program Scholarship
Projects and Grants: ARC Linkage Grant LP160100492
Date Deposited: 15 Jun 2021 01:06
FoR Codes: 31 BIOLOGICAL SCIENCES > 3103 Ecology > 310305 Marine and estuarine ecology (incl. marine ichthyology) @ 40%
41 ENVIRONMENTAL SCIENCES > 4102 Ecological applications > 410203 Ecosystem function @ 40%
41 ENVIRONMENTAL SCIENCES > 4104 Environmental management > 410401 Conservation and biodiversity @ 20%
SEO Codes: 18 ENVIRONMENTAL MANAGEMENT > 1805 Marine systems and management > 180501 Assessment and management of benthic marine ecosystems @ 70%
18 ENVIRONMENTAL MANAGEMENT > 1802 Coastal and estuarine systems and management > 180201 Assessment and management of coastal and estuarine ecosystems @ 30%
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