Impacts of urbanisation on vertebrate scavengers at estuarine interfaces
Background & Rationale
Carrion is a critical resource for a variety of animal consumers in many types of ecosystems.
The ecological role of animal carcasses is particularly significant at interface regions such as
ocean beaches that are energetically supported by the import of carbon from abutting
systems1. Scavengers at interface regions are fundamentally important for the processing of
organic matter and they functionally couple habitats by acting as biological vectors that
bridge habitat boundaries2. Because scavengers at interfaces comprise threatened species
(e.g. raptors), invasive species (e.g. foxes and wild pigs) and feral species (e.g. cats, dogs),
and because scavengers are sensitive to human habitat changes (e.g. impacts of
urbanisation), understanding scavenger ecology has tangible conservation consequences3.
Estuaries of SE–Queensland form, besides sandy beaches, the major transition zones and
ecological interfaces in the coastal zone. Estuarine interfaces of the region provide
important habitats for terrestrial species, especially those associated with mangroves and
mudflats (e.g. shorebirds, raptors, small mammals, reptiles). Such estuarine habitats become
particularly valuable in increasingly-urbanised landscapes where habitats are progressively
lost upland from estuaries and beaches. Because estuarine interfaces are also predicted to
be hotspots of carbon processing, including carrion consumption by invasive and threatened
vertebrate scavengers, conservation management of estuaries in SE-Queensland requires
empirical data on these functions: this project will deliver, for the first time, critical baseline
data on these processes for the region.
Objective(s)
Fig. 1 Examples of vertebrates
scavenging fish on estuarine shores
(top: red fox, bottom: whistling kite)
recorded with camera traps in
mangrove forests of eastern
Moreton Bay. (Sep. 2013,Photos:
Schlacher, Huijbers).
1.) Map vertebrate scavenger species distribution and diversity at estuarine interfaces;
2.) Quantify rates of carrion processing and species identity of carcass consumption on estuarine shorelines;
3.) Assess the effect(s) of urbanisation on the composition and diversity of estuarine scavengers.
Approach
Synoptic field surveys of scavengers using baited (fish) IR – and motion-triggered camera traps. All major estuaries (i.e. those
regularly assessed by the Estuarine Health Monitoring Program http://www.healthywaterways.org/ehmphome.aspx for water
quality) will be sampled, with ten camera sites distributed from the mouth to the tidal limit. The estuaries cover a broad range of
land-use and span an urbanisation gradient from largely natural (Noosa) to highly-urban (e.g. Nerang - Broadwater). The project
team has extensive experience in the use of camera traps for coastal scavenger surveys (http://youtu.be/-1fea7mFpf8 ). We have
also recently conducted extensive field trials of the camera set-up in mangroves, confirming effective data collection on vegetated,
estuarine shores (Fig. 1).
Project Team, Supervisors & Collaboration
This is a joint proposal by the ‘Collaborative Research Network (CRN) – Water Science’ of Griffith University (GU) and the University of the Sunshine Coast (http://youtu.be/-1fea7mFpf8 ). Our team has wide‐ranging and extensive experience in environmental assessment, conservation biology, and coastal ecology, with matching and complementary expertise directly relevant to this proposal. Supervisors: Primary: A/Prof Thomas Schlacher (USC): coastal ecology, food webs of beaches and estuaries, scavenger biology ‐ raptors; Secondary: Dr Andrew OIds (USC): marine conservation planning; reserve design, reefs and reef fishes, estuarine food webs; Collaborators: Prof Rod Connolly (GU): food‐webs, coastal carbon processing, conservation planning, mangroves; Dr Chantal Huijbers (GU): urbanisation effects; animal movement; nearshore scavengers; isotope tracing; A/Prof David Schoeman (USC): numerical analysis, beach food webs, modelling, statistics, Key Literature
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2
3
Schlacher TA et al. PLoS ONE 8, e68221 (2013);
Schlacher TA et al. Acta Oecologica 48, 7-12 (2013);
Huijbers CM et al. Landscape and Urban Planning 119, 1– 8 (2013);