Environmental Statement volume 4 - Chiltern Evergreen3

Chiltern Line, Oxford - Bicester August 2009Otter and Water Vole Report4.0 Assessment4.1 Water Voles prefer continuous cover, densely vegetated ba nks and pl enty of emerge ntvegetation, whi ch wa s availabl e in most of the stret ches o f water course. However,historically th ere have be en a great d eal of Mi nk in the area tha t have im pacted on WaterVole populations. Within 18 months of mink breeding in an area a Water Vole population canbe wiped out through predation (Strachan et al, 2006). This combined with the ab sence ofany eviden ce of Water Vo le activity during t he cou rse of the su rvey means the sp ecies islikely absent from the site.4.2 Otters h ave a large a nd variable h ome rang e sel ecting area s o f lo w disturb ance wh ereverpossible (EA, 2002 ). Evidence of otter was not fou nd on all the Water Courses su rveyed,however considering the spread of field signs from the small streams in the north to main riverchannels around Oxford a t the southe rn end of the Scheme;, it may be a ssumed that Ottersare using most of the water courses that are crossed by the Railway line.4.3 However, despite a number of potential holts and hovers being observed no actual holts wereidentified.4.4 Otters are li sted on the UK BAP hence t hey are both a locall y and nationally importantspecies.Keystone Environmental 10