RECOVERY OF THE OTTER LUTRA LUTRA IN DENMARK MONITORED BY FIELD SURVEYS AND COLLECTION OF CARCASSES

Abstract

ABSTRACT- The otter Lutra lutra suffered serious declines in Denmark during the 1960s and 1970s. A series of conservation and management projects were initiated to protect the remnant population, including national surveys and collection of otter carcasses. The recov-ery of the otter in Denmark since the 1980s was described by four national field surveys in 1984-86, 1991, 1996 and 2004 following the standard otter survey method, and by the geo-graphical distribution of otter carcasses collected in 5-year periods prior to the field surveys. The surveys document a substantial increase in distribution range during the past 20 years. The number of collected carcasses increased annually by 9.1 ± 0.7 % (mean ± S.E.) between 1980-2003. The spatial distribution of carcasses collected in the 5-year period prior to field surveys was correlated with regional site occupancy in field surveys. The implemented man-agement practices are presented and discussed. We conclude that the standard otter survey method is a reliable method to monitor otter distribution range in Danish habitats, and that compiling records of otter casualties is a suitable methods to monitor long-term population trends. Key words: distribution range, Lutra lutra, monitoring, otter, population trend, standard sur-vey RIASSUNTO – L’espansione della Lontra Lutra lutra in Danimarca monitorata tramite rilevamenti di campo e la raccolta delle carcasse. In seguito al netto declino subito in Danimarca dalla Lontra Lutra lutra durante gli anni ’60 e ’70, è stata avviata una serie di progetti di conservazione e di gestione, incluse indagini di campo e raccolta di carcasse, finalizzati alla protezione della popolazione residua. A partire dagli anni ’80, il trend della