The ecology of otters (Lutia lutia L.) was studied at a number of locations to investigate specific aspects of carnivore behaviours and trophic niche breadth. Otter inhabiting the Gower Peninsular, in South Wales, ate freshwater fish (58.7%), marine fish (24.6%), non-fish (16.2%) and unidentified prey (0.6%). Bullhead was the core prey on Gower, although eel, stickleback, flatfish, brown trout and amphibians were also important dietary components. There was significant temporal and spatial variation in the composition of otter diet on Gower. A year long study of otters on the Pembrokeshire coast found that diet was composed of marine fish (56%), freshwater fish (29%) and non-fish prey (15%). O tter diet was very diverse on Gower and the Pembrokeshire coast, with slow swimming demersal fish the most frequent prey items. A systematic meta-analytical review of otter dietary studies demonstrated that otters have a very brbad trophic niche across Europe (H' - 0.77) and suggested that otters are facultative foragers. There was no evidence of latitudinal or Mediterranean trends in trophic diversity. Variation in trophic diversity and dietary composition appeared to be driven at the habitat level. A rigorous assessment of the techniques used to monitor otter populations and investigate otter diet was also undertaken. The standard 600 m transect used to determine otter distribution was inadequate at detecting otters on small lowland rivers, due to a high rate of type II error. Increasing transect size, making repeat visits and surveying additional sites improved the detection power of otter surveys. Five different spraint analysis methods produced dietary data with a low level of comparability. Potential limitations of volumetric analysis in highly diverse diets were identified. Molecular tools and new technologies need to be applied in carnivore dietary studies to advance theories of foraging, competition and lifehistory strategies.
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:678675 |
| Date | January 2010 |
| Creators | Parry, Gareth Stephen |
| Publisher | Swansea University |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Source | https://cronfa.swan.ac.uk/Record/cronfa42984 |
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