The conservation of juniper: the fauna of food-plant island sites in southern England.
Abstract
In southern England, 25 sites of indigenous juniper (Juniperus communis) visited in 1968-69 were considered as islands, since they tended to consist of concentrated groups somewhat isolated from one another. Since juniper is declining in numbers and conservation measures may be appropriate, the relationship between the specifically phytophagous fauna and the characteristics of the sampled sites were investigated in the light of biogeographical theories. Lists are given (with the frequency at each site) of 14 arthropod species found on sites in the North Downs in 1968, and of the same species with 1 additional one found on sites in the Chilterns in 1969. Oligonychus ununguis (Jac.), Cinara juniperi (Deg.) and Eupithecia pusillata (Den. & Schiff.) were the most common species in both regions, and the 3 species feeding on juniper fruits (Cyphostethus tristriatus (F.), Megastigmus bipunctatus (Swed.) and Argyresthia praecocella Zell.) were the species most rarely found. The number of species per site tended to vary according to the size of the site; bush age appeared to affect species composition on the North Downs but not on the Chilterns sites; and the degree of isolation of the site was not usually an important factor in species composition.