Structure of an otter (Lutra lutra) population in Germany – results of DNA and hormone analyses from faecal samples

Abstract

Population size, one of the basic biological parameters is particularly difficult to estimate for nocturnal animals with cryptic life style and little individual distinctiveness like Eurasian otters (Lutra lutra). Because telemetric methods often fail and also expose the animals to a high risk of injuries and even mortality, we analysed DNA and hormones of spraints to obtain data on population density and structure of free-living otters in a Nature Park in north-eastern Germany. We were able to assign 53 different individual profiles from faecal samples and obtained six more profiles from animals found dead inside the park. The total population estimate (n ¼ 59) consisted of at least 32 males and 27 females; 33 animals were adult, 23 younger than 2 years (three of unknown age). Marking points were frequented by up to 12 individuals. Estimated density was one animal per 4.7 km of shoreline. The genotypically estimated total population size was more than 2.5 times as high as estimated in the past census. The method was also suited to compare otter population densities in different areas or at different times in the same area.

The accuracy of scat identification in distribution surveys: American mink, Neovison vison, in the northern highlands of Scotland

“…The most likely explanation for the failures is degraded DNA (due to samples that were not fresh, or that had been subject to adverse weather conditions, cf. Kalz et al [2006]). Other studies have found similar success rates (e.g.…”

Y-chromosomal markers for the European brown hare (Lepus europaeus, Pallas 1778)

“…However, the matrilinear inheritance of mtDNA may introduce some bias into such analyses because the male lineage does not contribute to the outcome (Lindgren et al 2004). In species with philopatric females and dispersing males, such as the European brown hare (Fickel 2003;Fickel et al 1999Fickel et al , 2005 or in species where only very few matrilineages exist such as in the Eurasian otter Lutra lutra (Kalz et al 2006), it is necessary to overcome this obstacle. Therefore, researchers often use nuclear markers that are inherited biparentally and thus also take into account the male lineage (Burton et al 2002).…”

Monitoring physiological stress in semi-free ranging populations of an endangered Australian marsupial, the Greater Bilby (Macrotis lagotis)

“…Non-invasive FCM analysis has contributed new knowledge in relation to wildlife management (Bosacker 2008;Thaker et al 2010), population density (Kalz et al 2006;Park et al 2011), behaviour and social status (Muller and Wrangham 2004), reproduction (Hesterman et al 2008), sociality (Bosacker 2008), territoriality (Barja et al 2008), animal welfare (Owen et al 2004), health status (Chapman et al 2007), predation threat (Sheriff et al 2009), and to predict population declines and mortality (McDonald et al 1981;Ellenberg et al 2007). As with any emerging quantitative physiological method, non-invasive analysis of glucocorticoids has pros and cons that need to be considered for each new study species for which this technique is being developed (Narayan 2013).…”