Dugong habitat use in relation to seagrass nutrients, tides, and diel cycles

Sheppard, James K., Marsh, Helene, Jones, Rhondda E., and Lawler, Ivan R. (2010) Dugong habitat use in relation to seagrass nutrients, tides, and diel cycles. Marine Mammal Science, 26 (4). pp. 855-879.

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The dugong is the only herbivorousmammal that is strictly marine and a seagrass community specialist. The pasture available to the dugong varies with the tides because seagrass occurs in both intertidal and subtidal areas. We GPS-tracked seven dugongs within a 24 km2, intensively used seagrass habitat in subtropical Australia in winter.We modeled resource selection within the habitat by comparing the dugongs’ use of space with the distribution of seagrass in an area defined using the combined space-use of the tracked animals. Selection by dugongs for seagrass quantity (biomass) and quality (nutrients) was analyzed within six time/tide combinations to examine the influences of tidal periodicity and the diel cycle on resource selection. Dugong habitat use was consistently centered over seagrass patches with high nitrogen concentrations, except during the day at low tides when the animals had fewer habitat choices and their space use was centered over high seagrass biomass. The association of dugongs with seagrass high in starch was positive during both day and night high tides when the animals could access the intertidal areas where seagrass biomass was generally low. Associations between dugongs and seagrass species were less definite, reflecting the potential for dugongs to exploit several species. Our model of dugong resource selection suggests that nitrogen is the primary limiting nutrient for dugong populations and also confirms the preference of dugongs for high-energy foods.

Item ID: 12171
Item Type: Article (Research - C1)
ISSN: 1748-7692
Keywords: dugong, Dugong dugon, grazer, resource selection, seagrass, utilization distribution, GPS-telemetry
Date Deposited: 01 Nov 2010 22:12
FoR Codes: 06 BIOLOGICAL SCIENCES > 0602 Ecology > 060201 Behavioural Ecology @ 50%
06 BIOLOGICAL SCIENCES > 0602 Ecology > 060205 Marine and Estuarine Ecology (incl Marine Ichthyology) @ 50%
SEO Codes: 96 ENVIRONMENT > 9608 Flora, Fauna and Biodiversity > 960808 Marine Flora, Fauna and Biodiversity @ 100%
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