Feeding across the food web: The interaction between diet, movement and body size in estuarine crocodiles (Crocodylus porosus)

• DOI: 10.1111/aec.12212
• Publication Date: 2014-12-09T07:05:18Z
• Authors: Jeffrey O. Hanson; Steven W. Salisbury; Hamish A. Campbell; Ross G. Dwyer; Timothy D. Jardine; Craig E. Franklin
• Keywords: 0106 biological sciences; Evolution; Discrimination factor; 15. Life on land; Stable isotope; 01 natural sciences; Apex predator; 1105 Ecology; Environmental sciences; Home range; Biological sciences; Behavior and Systematics; Ecosystem function; Acoustic telemetry; 14. Life underwater; 2303 Ecology

Abstract The estuarine crocodile ( C rocodylus porosus ) is an apex predator across freshwater, and coastal environments. impact of a changing . population upon the ecosystem unknown, but due to large ontogenetic changes in body mass (>1000‐fold) their may be wide reaching substantial. Here we investigated relationship between diet, movement size inhabiting tidal river northern Australia. Subcutaneous acoustic transmitters fixed underwater receivers were used determine activity space patterns 42 individuals (202–451 cm total length). There was no size‐related spatial partitioning among different sized crocodiles. Large (snout–vent length SVL ): 160 < 188.5 cm) did, however, exhibit much larger than other classes. Diet individual specialization assessed using composition stable carbon δ 13 nitrogen 15 N isotopes tissues with turnover rates. quadratic , suggesting that medium‐sized (110 incorporated greater proportion high trophic prey into diets small 110 or > cm). Tissue on hand positively correlated size, indicating classes trophically linked primary producers habitats. Individual‐level analyses showed crocodiles generalist feeders while medium specialized particular items within food webs they fed. findings further our understanding variation suggest change demographics influential at various levels local web.