Abstract
Knowledge of the effect of habitat type and region on diet and feeding behaviours of a species facilitates a better understanding of factors impacting populations, which contributes to effective conservation management. Using spraint analysis and relative frequency of occurrence data from the literature, we described the dietary patterns of Eurasian otters (Lutra lutra) in 23 study sites within the Pannonian biogeographical region in Hungary. Our results indicated that diet composition varied by habitat type and is therefore context dependant. The differences among habitat types were however lower than expected. We noticed a decline in the fish consumption with a concomitant increase in trophic niche breadth and amphibian consumption in rivers, ponds (fish farms), backwaters, marshes and small watercourses. The main differences in diet were not attributed to the consumption of primary and secondary food types (fish and amphibians), but rather to differences in other, less important food types (mammals, birds). Using hierarchical cluster analysis, rivers and ponds could clearly be separated from other habitat types. We found the main fish diet of otters in most of these areas consisted of small (<100 g), eurytopic, littoral and non-native, mostly invasive species. Dietary studies from 91 sites in six European biogeographical regions showed that fish are consumed most frequently in the Atlantic and Boreal, less in the Continental and Pannonian, and least in the Alpine and Mediterranean regions. Comparative analysis indicated that the Mediterranean region (with frequent crayfish consumption) and Alpine region (frequent amphibian consumption) cluster separate from the other regions.
Highlights
A thorough understanding of the diet, which largely defines the ecological niche of a species is an essential element in determining what limits populations (e.g., mortality, breedingHow to cite this article Lanszki et al (2016), Diet of otters (Lutra lutra) in various habitat types in the Pannonian biogeographical region compared to other regions of Europe
This study focuses on the Eurasian otter (Lutra lutra Linnaeus, 1758) which is widely distributed in Europe, Asia and part of North-Africa (Conroy & Chanin, 2002; EEA, 2009)
In the Pannonian data set the distribution of the seven main food types consumed by otters differed significantly between habitat types (Chi-square test: χ224 = 722.05, P < 0.0001)
Summary
A thorough understanding of the diet, which largely defines the ecological niche of a species is an essential element in determining what limits populations (e.g., mortality, breedingHow to cite this article Lanszki et al (2016), Diet of otters (Lutra lutra) in various habitat types in the Pannonian biogeographical region compared to other regions of Europe. Food is often limited (Macdonald, 1983) and diets may vary between regions (e.g., Zalewski, 2004; Kruuk, 2006; Lozano, Moleon & Virgós, 2006). During these periods of food shortage less preferred foods are often taken. Understanding these limitations and differences allows for planning an effective context-specific conservation strategy. A theoretical basis for population density estimation and carrying capacity in different habitats is important for conservation management (Hayward, O’Brien & Kerley, 2007)
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