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.
