 Alder trees are also at risk at the reserve, this time from a fungal disease caused by "Phytophthora alni".Being water-borne, this infection could spread to all the alders on the site.Another natural threat is that of the introduced Harlequin ladybird which was first identified at the site in June 2008 and is a severe threat to the native seven-spot ladybird population as it is such an effective aphid predator.