The Web of Death: Scavenger Communities and Interactions on Carrion in Australian Landscapes

Abstract

Carrion is a nutrient-rich resource that attracts a diverse community of organisms, from insects and vertebrates to microbes. These organisms engage in a series of complex interactions, as they compete for a shared resource that is generally ephemeral and patchy in distribution. Carrion consumers may also interact with surrounding ecosystems, as they contribute to nutrient cycling and dispersal, and to carrion removal, which can limit potential disease spread. Further, as most animals that interact with carrion also take on predatory roles, carrion may impact local environments by enhancing or redirecting predation or fear effects. These interactions are largely shaped by the ecosystem context in which the carcass is situated. Yet there remains a paucity of data on the different environmental drivers affecting carrion ecology generally, especially in Australian environments. This thesis addressed this gap by exploring key aspects of the carrion community in Australia. It applies a large-scale standardised survey of the vertebrates and insects associated with over 120 experimentally positioned kangaroo (Osphranter and Macropus spp.) carcasses in three distinct biogeographic regions across Australia. Overall, this work comprises the largest replicated carrion ecology experiment on mainland Australia to date. The findings reveal novel insights into the structure and function of carrion communities across a range of bioregions. They also highlight the context dependency of carrion communities and their various interactions. I suggest that future work focuses on enhancing the spatial, temporal, and taxonomic scales upon which carrion research is focused, and support the development of global, standardised carcass monitoring surveys to build a more in-depth understanding of the factors that influence carrion community dynamics and ecosystem processes linked to decomposition.