A non-invasive approach to determining pine marten abundance and predation

A non-invasive approach was used to investigate variation in pine marten (Martes martes) abundance between the midlands and east of Ireland, and to determine the frequency of occurrence of squirrels and other small mammals in the diet. Remotely plucked hair samples were genotyped to differentiate between individual animals, and real-time polymerase chain reaction (PCR) was used to identify predator and prey DNA in scats. Macro analysis of prey remains was carried out on a sub sample of scats and the results from both methods are compared. Non-invasive techniques were successful in determining the presence and relative abundance of the pine marten at woodland level. As expected, abundance was found to be higher in the core population of the midlands than in the east. Pine martens were found to reach higher numbers per km² of forested habitat in Ireland than their British or European counterparts. Both traditional hard part analysis and molecular dietary analysis of mammalian prey yielded similar results. We provide the first evidence of the European pine marten predating upon the North American grey squirrel (Sciurus carolinensis) in its invasive range. While the grey squirrel was not available as a prey item in any of the midlands sites, it was available in the east, where it featured significantly more frequently in the diet than the native red squirrel. In both the midlands and the east the woodmouse is the most frequently occurring mammal in the diet.