The Eurasian Otter’s habitat in northeastern Slovenia includes the channel of the old Drava River with its tributaries, where gravel bars and floodplain forests have been preserved till this day.
The otter is endangered largely by inappropriate encroachments upon watercourses (e.g. regulations, expulsion of riparian vegetation), water pollution and traffic (unsuitable road bridging). As the otters find cover, resting places and dens in the riparian growth, the expulsion of trees and scrubs has a negative impact on the quality of their natural environment. The presence of tree and scrub vegetation increases the availability of invertebrates, which constitute an important food source for fish, which most often appear on the Otter's menu. For the long-term conservation of otters, it is therefore of utmost importance to protect the applicable dynamic water and land habitats as well as corridors that connect them. As these aquatic animals generally live alone and have large territories (even more than 20 km of watercourse), their density in a given area is never high.
We shall enhance the interconnection of aquatic habitats with sustainable regulation of the Drava’s tributaries. Furthermore, we shall indirectly contribute to a more favourable microclimate of the area as well as greater local species diversity. To raise public awareness as to the importance of the Otter’s conservation, its habitats and natural river processes, educational and interpretation units will be set up.
What can we do to improve the conservation status of the Otter?
- Let us not pollute the water.
- Let us not encroach upon watercourses.
- Let us preserve hedgerows and riparian vegetation.
- Let us adjust the speed on the roads.
- Let us not make noise in the Otter’s habitat, and make sure to keep dogs on a leash.
Why do we need the Otter?
The Otter is a predator and at the top of the food chain in the aquatic ecosystem. Its disappearance would badly affect not only the species composition but also the abundance of the species that constitute its prey.
As an umbrella species, the Otter is a good indicator of the natural environment’s state of conservation. As it cannot find food in highly polluted waters, it can be less common in them or even completely absent. The problem lies predominantly in heavy metals (mercury, PCBs), which accumulate in the Otter's body through the food chain and evidently badly affect its behaviour, reproductive ability and mortality.
Sources and literature
- Chanin, P. (2003). Ecology of the European Otter. Conserving Natura 2000 Rivers. Ecology Series No. 10. Peterborough: English Nature.
- Gregorc, T., Hönigsfeld Adamič, M., Toplak, N. (2015). Ocena velikosti populacije vidre (Lutra lutra) s pomočjo DNA analize na reki Muri. Ljubljana: Lutra, Inštitut ohranjanje naravne dediščine.
- Gregorc, T., Zavratnik, S. (2017). Zimski monitoring (Lutra lutra) na Goričkem. Projekt: Raznoživost pod Vidrino streho na Goričkem. Zaključno poročilo. Ljubljana: Lutra, Inštitut ohranjanje naravne dediščine.
- Hönigsfeld, A. M., Gregorc, T., Nekrep, I., Mohar, P., Torkar, G. (2009). Inventarizacija vidre (Lutra lutra) in drugih večjih vodnih sesalcev na Ljubljanskem barju in z njim povezanih vodnih ekosistemih Ljubljana: Lutra, Inštitut za ohranjanje naravne dediščine..
- Madsen, A.B., Prang, A. (20019. Habitat factors and the presence or absence of otters Lutra lutra in Denmark. Acta Theriologica 46 (2): 171–179.
- Ozoliņš, J., Ornicāns, A., Stepanova, A., Lūkins, M., Dukule-Jakušenoka, K., Šuba, J., Pilāte, D., Bagrade, G. (2018). Action Plan for Eurasian otter Lutra lutra Conservation. LSFRI Silava, Salaspils.
- Ruiz-Olmo, J., Jimenez, J. (2008). Diet diversity and breeding of top predators are determined by habitat stability and structure: a case study with the Eurasian otter (Lutra lutra L.). European Journal of Wildlife Research, 55, 2: 133–144.
- Lanszki, J., Bauer-Haáz, A. E., Széles, L. G., Heltai, M. (2015). Diet and Feeding Habits of the Eurasian Otter (Lutra lutra ): Experiences from Post mortem Analysi. Mammal Study 40: 1–11.