New urban developments that retain more remnant trees have greater bird diversity

The rapid expansion of urban landscapes has significant consequences for wildlife. Habitat loss and fragmentation cause significant loss of species richness. While remnant fragments of habitat are important areas for conservation, the urban matrix between fragments is also critical. Increasing the suitability of the matrix for wildlife can increase the diversity of wildlife that utilise urban landscapes and increases the potential for dispersal among fragments. We investigated the effectiveness of retaining remnant trees during for increasing the species richness and abundance of birds in new urban housing developments. We measured species richness and abundance in four habitat types: non-vegetated streets, vegetated streets, recreational parks and bush sites. We discovered that the number of bird species observed was lowest on the non-vegetated streets and highest within the bush fragments. Species richness on vegetated streets was intermediate between non-vegetated streets and parks. The abundance of birds was highest within recreational parks and we observed significantly more birds on vegetated streets than non-vegetated streets. Additionally, we found the number of species and total abundance of birds was positively associated with the total number of retained mature trees within a vegetated street. The dominant feeding guild and species composition varied between the different habitat types. Our findings suggest that increasing the number of retained mature trees in new housing developments may be an effective means of increasing the number of bird species that utilise the urban matrix.