Conservation planning and management of habitat for a diverse bird community in urban and future urban areas

Abstract

Rapid urbanisation is altering biodiversity patterns worldwide. Previous studies have shown that urban areas vary in their capacity to support biodiversity, suggesting that the appropriate design of urban landscapes could lead to improved outcomes for biodiversity conservation. To design biodiversity-friendly urban landscapes, conservationists, policy-makers, planners and developers must understand what landscape features are valuable for biodiversity.

My research focused on patterns of landscape use by birds in urban and future urban areas in Canberra, Australia. My overarchng aim was to provide whole-of-landscape scientific evidence on which to base planning, management and conservation priorities. My major research quesions were: (1) What are the relationships between birds and their habitat in urban and future urban landscapes? (2) How can we use this information to guide urban planning and management strategies to achieve positive conservation outcomes for a diverse bird community? I approached these questions from three perspectives representing the spectrum of urbanisation: from landscapes on the brink of urbanisation, to the urban fringe, to established urban areas.

The first part of my research focused on an area scheduled for urban development. I investigated the relationshp between birds and their habitat, and underlying relationships betwen bird life-history and traits and environmental characteristics. I showed that woodlands and river corridors supported high bird species richness, including woodland dependent species, and that habitat structure and composition were important in explaining the presence of sensitive woodland species. I demonstrated that species that forage and nest on the ground and in the understory strata, and smaller-bodied species would be most negatively affected by loss of habitat due to planned urbanisation.

The second part of my research focussed on the urban fringe: the interface at which surburbs and protected areas meet. I showed that bird species and abundance were similar between suburbs and adjacent reserves, but that reserves supported a more distinct and hetrogeneous community than suburbs, reflected in differences in the relative proportions of functional guilds between the two habitats. I also showed that suburbs with {u2265}30% native (Eucalyptus) street trees, as well as reserves adjacent to these suburbs, supported significantly higher bird species richness - demonstrating that suburban management practices significantly affect nearby protected areas.

The third and final part of my research focused on small green spaces within established urban areas. I confirmed that large eucalypt trees are keystone structures in urban parks that provide crucial habitat resources for birds, thereby increasing overall bird species richness, abundance and probability of breeding, as well as increasing woodland species richness and affecting community composition. I demonstrated that parks in neighbourhoods with high public green space (corresponding to less residential land) supported more individual birds, more bird species overall, and more woodland-dependent species, insectivores and hollow nesters. Suburban growth strategies that increase residential density may therefore have negative effects on some common urban birds.

Collectively, my surveys across the range of habitats present in Canberra's urban and future urban environments enabled me to to develop evidence-based urban planning, policy and management strategies to improve conservation outcomes in urban landscapes.