Arthropods on street trees: a food resource for wildlife

Abstract

As with most cities throughout the world, the Western Australian city of Perth is beautified with rows of street trees. Here, the choice of trees tends to be dictated by their hardiness and ease of cultivation (e.g., Queensland Box Lophostemon confertus), their perceived beauty (e.g., Lemon Scented Gum Eucalyptus citriodora) and the affiliation with species from regions where many of the settlers originated (e.g., London Plane Tree Platanus acerifolia). Evidence indicates that the abundance and diversity of arthropods on a tree species is, to a large extent, a reflection of the tree in recent geological history ? the more recent the arrival, the less arthropods are likely to occur on it (Southwood 1960, 1961). From work with native eucalypt species, Recher et al. (1996) have found that arthropod density and diversity differs markedly between tree species within an ecosystem, and this phenomenon flows through to the insectivorous birds which forage on these trees. Those species with high levels of arthropods, such as Narrow-leaved Ironbark E. crebra in New South Wales are visited by pardalotes, thornbills and weebills to a much greater extent than the co-dominant Grey Box E. moluccana (Recher et al. 1994).