Smoke and Mirrors

: The effect of urbanisation and fire on the bird assemblages of the Darwin region

Abstract

This research aimed to investigate the response of the avian communities of the
Darwin region, in north Australia, to twenty years of profound land use change, urban
growth, and increasingly intense annual fires occurring in both the urban and peri-urban zone.

Land use change and inappropriate fire regimes pose a significant threat to global
biodiversity. Understanding how these factors affect biota, independently and interactively,
is essential for fire management and urban planning strategies. Birds, with their widespread
appeal and ready identifiability, are significant indicators to monitor environmental change.

To accomplish the research aims: (1) I collated and assessed historical bird data to
provide a broad overview of trends and changes, and to guide further analyses; (2)
developed novel data-gathering methods, with UAV and bio-acoustic monitoring, in
conjunction with traditional surveying to ascertain current avian assemblages; (3) created
spatial data sets to map land use change and fire history over a 20-year period; and (4) used
the derived spatial data sets, historical and recent avian assemblage data, and investigated
the impact of land use change and fire regimes, individually and interactively, on bird
communities in different habitats within the Darwin urban and peri-urban region.

The research found that urban bird assemblages are largely unaffected by land use
change overall. However, an examination of individual habitat types uncovered significant
changes, with notable declines and increases in some feeding guild species. This study also
determined that land use change is having a profound impact on the fire regimes of the
Darwin region and this, consequently, is affecting avian communities within specific habitats
more markedly than land use change alone. Further, it was revealed that land use change
and fire regimes are interacting and significantly affecting frugivores in the Darwin region.
Supplemental to the main body of research, the use of drones and bioacoustic technology
as an affordable aid to wildlife surveying was demonstrated and validated

The findings of this study highlight the necessity of understanding the effects of
increasing urbanisation and land use change on bird communities if Darwin is to preserve
avian diversity and prevent the establishment of invasive species, as has occurred in other
Australian capital cities. Of greater importance, this research is the first to examine the direct
interactive effects of two environmental stressors, fire and land use change on any vertebrate species,
the knowledge of which is crucial for biodiversity conservation worldwide.

Date of Award	2023
Original language	English
Awarding Institution	Charles Darwin University (CDU)
Supervisor	Andrew Edwards (Supervisor), Patrice Weber (Supervisor) & Stephen Garnett (Supervisor)